孟憲欣,管澤毅,葛吉生,王希柳,秦永生,王大寧,彭 朋*
間歇運(yùn)動(dòng)干預(yù)自發(fā)性高血壓大鼠病理性心臟肥大:運(yùn)動(dòng)強(qiáng)度與健康效應(yīng)的關(guān)系
孟憲欣1,管澤毅1,葛吉生1,王希柳1,秦永生2,王大寧2,彭 朋2*
(1.青島大學(xué) 體育學(xué)院,山東 青島 266071;2.中國(guó)人民武裝警察部隊(duì)后勤學(xué)院 衛(wèi)生勤務(wù)系,天津 300309)
:體力活動(dòng)的健康促進(jìn)效應(yīng)與運(yùn)動(dòng)強(qiáng)度呈現(xiàn)劑量-反應(yīng)關(guān)系。中低強(qiáng)度持續(xù)有氧運(yùn)動(dòng)已成為諸多慢性非傳染性疾病患者(包括但不限于心力衰竭、高血壓、糖尿病、肥胖等)一級(jí)和二級(jí)預(yù)防的重要策略,然而間歇運(yùn)動(dòng)尤其是高強(qiáng)度間歇運(yùn)動(dòng)(HIIT)的療效(特別對(duì)心血管疾病患者)仍存在爭(zhēng)議。:對(duì)比長(zhǎng)期不同強(qiáng)度間歇運(yùn)動(dòng)對(duì)自發(fā)性高血壓大鼠(SHR)病理性心臟肥大的作用并在心臟形態(tài)、結(jié)構(gòu)、功能和分子等層面分析其調(diào)控機(jī)制,探討運(yùn)動(dòng)強(qiáng)度與健康效應(yīng)的關(guān)系,為制定針對(duì)心血管疾病患者的最佳運(yùn)動(dòng)康復(fù)處方提供循證依據(jù)和有效方法。:45只雄性SHR隨機(jī)分為安靜對(duì)照組(SHR-SED)、中等強(qiáng)度間歇運(yùn)動(dòng)組(SHR-MIIT)和HIIT組(SHR-HIIT),同時(shí)將15只年齡、性別相匹配的Wistar-Kyoto大鼠作為正常血壓組(WKY)。WKY和SHR-SED組動(dòng)物保持安靜狀態(tài),SHR-MIIT、SHR-HIIT組分別進(jìn)行18周MIIT或HIIT。末次實(shí)驗(yàn)后48 h利用無(wú)創(chuàng)血壓儀測(cè)定尾動(dòng)脈血壓,超聲心動(dòng)圖檢測(cè)心臟結(jié)構(gòu)與功能,H&E和Masson染色進(jìn)行組織病理學(xué)觀察并分別獲取心肌細(xì)胞橫斷面積(CSA)和間質(zhì)膠原容積分?jǐn)?shù)(CVF),RT-PCR法檢測(cè)心肌胚胎基因[心房鈉尿肽(ANP)、腦鈉肽(BNP)和β-肌球蛋白重鏈(β-MHC)]mRNA表達(dá)量,Western blot法檢測(cè)病理性[鈣調(diào)神經(jīng)磷酸酶/活化T細(xì)胞核因子(Cn/NFAT)]和生理性[磷脂酰肌醇-3激酶/Akt(PI3-K/Akt)]心臟肥大信號(hào)途徑各蛋白表達(dá)量。:1)心臟形態(tài)與結(jié)構(gòu):SHR-SED組左心室出現(xiàn)向心性肥大(心腔縮窄、室壁增厚、CSA升高),CVF增加(<0.05);SHR-MIIT組左心室發(fā)生離心性肥大(心腔擴(kuò)張、室壁厚度),CVF下降(<0.05);SHR-HIIT組心臟同樣發(fā)生離心性肥大,但心腔擴(kuò)張同時(shí)室壁變薄,CVF進(jìn)一步增加(<0.05)。2)心功能:SHR-SED組左心室射血分?jǐn)?shù)(LVEF)下降(<0.05);與SHR-SED組比較,SHR-MIIT組LVEF升高(<0.05),而SHR-HIIT組則進(jìn)一步下降(<0.05)。3)胚胎基因表達(dá):SHR-SED組ANP、BNP和β-MHC mRNA表達(dá)量均上調(diào)(<0.05);與SHR-SED組比較,SHR-MIIT組各胚胎基因表達(dá)量均下降(<0.05),SHR-HIIT組BNP和β-MHC升高(<0.05)。4)心臟肥大信號(hào)分子蛋白表達(dá):SHR-SED組CnAβ升高(<0.05)、p-NFATc3/t-NFATc3比值降低(<0.05),PI3-K(p110α)和p-Akt/t-Akt比值無(wú)顯著性變化(>0.05);與SHR-SED組比較,SHR-MIIT組CnAβ下降(<0.05),p-NFATc3/t-NFATc3比值、PI3-K(p110α)和p-Akt/t-Akt比值升高(<0.05),SHR-HIIT組CnAβ、PI3-K(p110α)和p-Akt/t-Akt比值升高(<0.05),p-NFATc3/ t-NFATc3比值下降(<0.05)。:長(zhǎng)期間歇運(yùn)動(dòng)對(duì)高血壓的健康效應(yīng)存在運(yùn)動(dòng)強(qiáng)度依賴性,MIIT誘導(dǎo)SHR心臟由病理性肥大向生理性肥大轉(zhuǎn)變并改善心功能,而HIIT則加重心臟重塑并加速心力衰竭進(jìn)展,其機(jī)制與不同強(qiáng)度間歇運(yùn)動(dòng)對(duì)心肌膠原代謝、胚胎基因表達(dá)以及Cn/NFAT和PI3-K/Akt信號(hào)通路的調(diào)控存在差異有關(guān)。因此,中等強(qiáng)度運(yùn)動(dòng)仍然是高血壓患者臨床康復(fù)的最佳方式,HIIT的安全性和有效性有待進(jìn)一步證實(shí)。
間歇運(yùn)動(dòng);運(yùn)動(dòng)強(qiáng)度;自發(fā)性高血壓大鼠;心臟肥大;心臟重塑
心臟肥大是高血壓患者心臟重塑的主要外在表現(xiàn),因心肌細(xì)胞體積增大和/或細(xì)胞外基質(zhì)(extracellular matrix,ECM)增多所致,最終導(dǎo)致心功能失代償以及心力衰竭,屬于“病理性心臟肥大”(Shenasa et al.,2017)。相反,運(yùn)動(dòng)員經(jīng)歷長(zhǎng)期規(guī)律訓(xùn)練同樣可發(fā)生心臟肥大,但心功能增強(qiáng)、運(yùn)動(dòng)能力提高,稱為“運(yùn)動(dòng)員心臟”,隸屬“生理性心臟肥大”(Bessem et al.,2018)。病理性與生理性心臟肥大具有本質(zhì)區(qū)別,其形成機(jī)制與不同信號(hào)途徑激活有關(guān)(Nakamura et al.,2018),鈣調(diào)神經(jīng)磷酸酶/活化T細(xì)胞核因子(calcineurin/nuclear factor of activation T cell,Cn/NFAT)和磷脂酰肌醇-3激酶/Akt(phosphoinositide 3-kinase/Akt,PI3-K/Akt)分別是介導(dǎo)兩種心臟肥大的主要信號(hào)轉(zhuǎn)導(dǎo)通路。
中低強(qiáng)度持續(xù)有氧運(yùn)動(dòng)(以下簡(jiǎn)稱“有氧運(yùn)動(dòng)”)是高血壓臨床運(yùn)動(dòng)康復(fù)的主要形式且已成為多種慢性非傳染性疾?。òǖ幌抻谛牧λソ?、高血壓、糖尿病、肥胖等)患者一級(jí)和二級(jí)預(yù)防的重要策略(Swift et al.,2013)。越來(lái)越多的證據(jù)顯示出運(yùn)動(dòng)對(duì)健康以及生活方式疾病的良好作用(Swift et al.,2013),因此個(gè)性化運(yùn)動(dòng)處方成為亟待解決的課題。研究證實(shí)(Hussain et al.,2016),體力活動(dòng)的健康促進(jìn)作用與運(yùn)動(dòng)強(qiáng)度呈現(xiàn)劑量-反應(yīng)關(guān)系,高強(qiáng)度運(yùn)動(dòng)的心臟健康效應(yīng)是中等強(qiáng)度的2倍。然而針對(duì)競(jìng)技運(yùn)動(dòng)員(Mousavi et al.,2009)以及實(shí)驗(yàn)動(dòng)物(Kaleta et al.,2017)的研究亦發(fā)現(xiàn),長(zhǎng)期高強(qiáng)度運(yùn)動(dòng)可引起心臟病理性重塑并誘發(fā)心血管不良事件。因此,運(yùn)動(dòng)的健康效應(yīng)存在“強(qiáng)度閾值”,超出這一閾值則造成適應(yīng)不良。
間歇運(yùn)動(dòng)是近年來(lái)競(jìng)技體育界與大眾健身領(lǐng)域新興的運(yùn)動(dòng)方式,按照強(qiáng)度可分為中等強(qiáng)度間歇運(yùn)動(dòng)(moderate-intensity interval training,MIIT)和高強(qiáng)度間歇運(yùn)動(dòng)(high-intensity interval training,HIIT),其中MIIT的作用較為肯定(Batacan et al.,2014; Borges et al.,2014),而HIIT對(duì)心臟(尤其是病理狀態(tài)下)的作用尚存在爭(zhēng)議(范朋琦 等,2018;王增喜 等,2018; Hafstad et al.,2013; Holloway et al.,2015; Lu et al.,2015; Novoa et al.,2017)。因此,本研究通過(guò)設(shè)計(jì)兩種不同強(qiáng)度間歇運(yùn)動(dòng)(即MIIT和HIIT),旨在對(duì)比長(zhǎng)期(18周)間歇運(yùn)動(dòng)對(duì)SHR心臟肥大的作用并在心臟形態(tài)、結(jié)構(gòu)、功能和分子等層面分析其調(diào)控機(jī)制,探討運(yùn)動(dòng)強(qiáng)度與健康效應(yīng)的關(guān)系。我們假設(shè),不同強(qiáng)度間歇運(yùn)動(dòng)均可改善SHR病理性心臟肥大并抑制心臟重塑,HIIT的效果理應(yīng)更為顯著。
45只12周齡SPF級(jí)雄性SHR,體質(zhì)量(220±18) g,購(gòu)自北京維通利華實(shí)驗(yàn)動(dòng)物技術(shù)有限公司,許可證號(hào):SCXK(京)2018-0027。將實(shí)驗(yàn)動(dòng)物隨機(jī)分為安靜對(duì)照組(SHR-sedentary,SHR-SED,=15)、MIIT組(SHR-MIIT,=15)和HIIT組(SHR-HIIT,=15),同時(shí)以15只同齡雄性Wistar-Kyoto大鼠作為正常血壓組(WKY)。動(dòng)物飼養(yǎng)環(huán)境:溫度20~22℃,1個(gè)標(biāo)準(zhǔn)大氣壓,相對(duì)濕度50%~60%,12:12 h明暗周期,分籠飼養(yǎng)(3只/籠),自由進(jìn)食水。
大鼠適應(yīng)環(huán)境1周后開始正式實(shí)驗(yàn)。WKY和SHR-SED組動(dòng)物保持安靜狀態(tài),SHR-MIIT、SHR-HIIT分別進(jìn)行18周MIIT或HIIT。在實(shí)驗(yàn)過(guò)程中,由于拒跑、意外死亡等原因,共剔除6只大鼠,因此最終樣本量=54,其中WKY組(=15)、SHR-SED組(=15)、SHR-MIIT組(=13)和SHR-HIIT組(=11)。
大鼠先進(jìn)行5天跑臺(tái)適應(yīng)性訓(xùn)練(速度:10~15 m/ min,坡度:0°,時(shí)間:30 min/天),隨后參照課題組前期建立的方法(范朋琦等,2018)測(cè)定大鼠運(yùn)動(dòng)能力:起始負(fù)荷為5 m/min,每2 min增加1.5 m/min,直至力竭(坡度始終為0°),記錄峰值跑速(peak running velocity,PRV)。
根據(jù)Hoydal等(2007)建立的大鼠跑速與最大攝氧量(maximal oxygen uptake,V?O2max)關(guān)系以及課題組前期研究(范朋琦等,2018)制定跑臺(tái)運(yùn)動(dòng)方案(表1),運(yùn)動(dòng)強(qiáng)度、運(yùn)動(dòng)時(shí)間、完成組數(shù)以及運(yùn)動(dòng)頻率逐漸遞增。分別于第4、8、12和16周重新測(cè)定PRV以及時(shí)調(diào)整運(yùn)動(dòng)強(qiáng)度(跑速)。
表1 18周運(yùn)動(dòng)方案
注:[5×(60% PRV×1 min+40% PRV×1 min)]×3表示以60% PRV運(yùn)動(dòng)1 min后以40% PRV運(yùn)動(dòng)1 min,依次交替重復(fù)5個(gè)循環(huán),3周/次,其他方案以此類推。
每周訓(xùn)練前以及末次訓(xùn)練后48 h,采用智能無(wú)創(chuàng)血壓測(cè)量?jī)x(BP-2010E,日本Softron Biotechnology公司)以Tail-Cuff法測(cè)定大鼠尾動(dòng)脈血壓,方法為:先將大鼠放入固定器中,隨后將固定器和大鼠尾部放置在預(yù)熱的加熱板上穩(wěn)定3 min,通過(guò)氣囊自動(dòng)加壓阻斷動(dòng)脈血流,讀取軟件顯示的收縮壓(systolic blood pressure,SBP)和舒張壓(diastolic blood pressure,DBP),連續(xù)測(cè)定3次,取均值。
末次血壓測(cè)定后稱量體質(zhì)量(body mass,BM),隨后腹腔注射戊巴比妥鈉(0.1 mg/kg)麻醉動(dòng)物并取仰臥位固定,胸部備皮,用高分辨率小動(dòng)物超聲影像系統(tǒng)(Vevo 3100,加拿大VisualSonics公司)檢測(cè)心臟結(jié)構(gòu)和功能,探頭頻率為14 MHz,(取胸骨旁左心室短軸切面進(jìn)行測(cè)量)取左心室乳頭肌水平進(jìn)行二維短軸掃描(M超),掃描速度100 mm/s。檢測(cè)參數(shù)包括:左心室舒張末期直徑(left ventricular end-diastolic diameter LVEDD)、左心室收縮末期直徑(left ventricular end- systolic diameter,LVESD)、左心室壁厚度(left ventricular wall thickness,LVWT)和左心室射血分?jǐn)?shù)(left ventricular ejection fraction,LVEF)。
超聲檢測(cè)后處死動(dòng)物,取出心臟后稱重(心臟質(zhì)量,heart mass,HM),迅速分離左心室(保留室間隔和左心室游離壁)并稱重(左心室質(zhì)量,left ventricular mass,LVM),分別計(jì)算與體質(zhì)量的比值作為心臟質(zhì)量指數(shù)(heart mass index,HMI)和左心室質(zhì)量指數(shù)(left ventricular mass index,LVMI)。在左心室最大橫徑處橫切將其分為兩部分,一部分用于心肌病理組織學(xué)觀察,另一部分用錫紙包裹投入液氮并迅速轉(zhuǎn)移至-80℃低溫冰箱凍存待測(cè)。分離腎上腺和胸腺并稱重,分別計(jì)算與體質(zhì)量的比值作為腎上腺質(zhì)量指數(shù)和胸腺質(zhì)量指數(shù)(代表慢性應(yīng)激參數(shù)),以檢測(cè)是否發(fā)生腎上腺肥大和胸腺萎縮。
于心臟橫切面取厚度為2 mm組織,用4%多聚甲醛溶液固定24 h,石蠟包埋并利用病理切片機(jī)(RM2255,德國(guó)徠卡儀器有限公司)制作5 μm切片。用蘇木素-伊紅(hematoxylin and eosin,H&E)染色心肌細(xì)胞,倒置相差顯微鏡(IX71,日本Olympus公司)下選取10個(gè)視野,觀察細(xì)胞排列、細(xì)胞核以及細(xì)胞形態(tài)等情況,用圖像分析軟件(Image Pro Plus 6.0,美國(guó)Media Cybernetics公司)測(cè)量心肌細(xì)胞橫斷面積(cross-sectional area,CSA)。用Masson染色膠原纖維,測(cè)量結(jié)締組織面積與所測(cè)視野面積的比值作為間質(zhì)膠原容積分?jǐn)?shù)(collagen volumetric fraction,CVF),測(cè)量?jī)x器、方法以及軟件同H&E染色。
RT-PCR法測(cè)定胚胎基因mRNA表達(dá)量,包括心房鈉尿肽(atrial natriuretic peptide,ANP)、腦鈉肽(brain natriuretic peptide,BNP)和β-肌球蛋白重鏈(β-myosin heavy chain,β-MHC)。取30 mg心肌組織按照Trizol試劑盒(武漢博士德生物工程有限公司)說(shuō)明提取總RNA,逆轉(zhuǎn)錄獲取cDNA,隨后利用實(shí)時(shí)熒光定量PCR儀(7500型,美國(guó)ABI公司)進(jìn)行RT-PCR,引物序列見表2。反應(yīng)體系為20 μL:上游和下游引物各0.4 μL,cDNA 2.0μL,SYBRTM-Green PCR Master-Mix 10 μL,dd H2O 7.2 μL。反應(yīng)條件:95℃預(yù)變性5 min;94℃變性20 s、60℃退火20 s、72℃延伸10 s,共40個(gè)循環(huán)。記錄循環(huán)閾值(Ct),以3-磷酸甘油醛脫氫酶(glyceraldehyde-3-phosphate dehydrogenase,GAPDH)為內(nèi)參,采用2-??Ct法分析mRNA含量并以各組與WYK組的比值作為相對(duì)表達(dá)量。
表2 引物序列
采用Western blot法檢測(cè)心肌蛋白表達(dá)量,包括CnAβ(Cn的催化亞基)、NFATc3(包括t-NFATc3和p-NFATc3)、PI3-K(p110α)(PI3-K的催化亞基)和Akt(包括t-Akt和p-Akt)(注:t-表示蛋白總量,p-表示該蛋白的磷酸化形式)。取100 mg心肌組織勻漿裂解后,4℃、13 000 rpm離心30 min,BCA法測(cè)定總蛋白濃度。取10 μg蛋白樣品在垂直電泳儀上經(jīng)12% SDS-PAGE分離后,轉(zhuǎn)移至PVDF膜上。兔抗鼠一抗(CnAβ,1:500;t-NFATc3,1:250;p-NFATc3,1:500;PI3-K(p110α),1:500;t-Akt,1:250;p-Akt,1:250;GAPDH,1:1 000)4℃靜置孵育過(guò)夜,TBST洗滌3次后加入二抗(辣根過(guò)氧化物酶標(biāo)記的羊抗兔IgG,1:5 000)37℃孵育1 h,TBST充分洗滌后,使用ECL發(fā)光成像,X線膠片壓片曝光,利用凝膠成像系統(tǒng)(ChemiDoc XRS,美國(guó)BIO-RAD公司)拍攝并掃描各條帶灰度值。GAPDH為內(nèi)參蛋白,以各組與WYK組的比值作為蛋白相對(duì)表達(dá)量。
使用SPSS 20.0進(jìn)行統(tǒng)計(jì)學(xué)處理與分析。所有數(shù)據(jù)用“均數(shù)±標(biāo)準(zhǔn)差”表示,血壓的時(shí)程變化使用重復(fù)測(cè)量的方差分析,4組間比較使用單因素方差分析(one-way ANOVA),多重比較采用檢驗(yàn)。統(tǒng)計(jì)學(xué)意義定為α=0.05。
血壓的時(shí)程動(dòng)態(tài)變化見圖1、圖2。與訓(xùn)練前(第0周)比較,WYK組SBP和DBP無(wú)顯著性變化(>0.05),SHR-SED組逐漸升高(<0.05),SHR-MIIT組逐漸下降(<0.05),SHR-HIIT組先下降后升高。與SHR-SED組比較,SHR-MIIT組和SHR-HIIT組在前10~11周逐漸下降(<0.05),隨后SHR-MIIT組持續(xù)下降(<0.05),而SHR-HIIT組SBP在第11~15周、DBP在12~18周時(shí)無(wú)顯著性差異(>0.05),SBP在第16~18周顯著性升高(<0.05)。
圖1 訓(xùn)練期間SBP的時(shí)程變化
Figure 1. Time Course Variation of SBP during Training
注:*<0.05,與SHR-SED組比較,下同。
圖2 訓(xùn)練期間DBP的時(shí)程變化
Figure 2. Time Course Variation of DBP during Training
通過(guò)計(jì)量學(xué)與超聲檢測(cè)觀察心臟結(jié)構(gòu)與功能(表3),結(jié)果顯示:與WYK組比較,SHR-SED組BM、LVEDD和LVEF下降(<0.05),HM、HMI、LVM、LVMI和LVWT升高(<0.05);與SHR-SED組比較,SHR-MIIT組HM、HMI、LVM和LVMI無(wú)顯著性差異(>0.05),LVEDD、LVWT和LVEF升高(<0.05),SHR-HIIT組HM、HMI、LVM、LVMI、LVEDD和LVESD升高(<0.05),LVEF下降(<0.05);與SHR-MIIT組比較,SHR-HIIT組HM、HMI、LVM、LVMI、LVEDD和LVESD升高(<0.05),LVWT和LVEF降低(<0.05)。
表3 心臟結(jié)構(gòu)與功能
注:*<0.05,與WKY組比較;#<0.05,與SHR-SED組比較;&<0.05,與SHR-MIIT組比較。
圖3顯示,胞漿呈紅色,胞核呈藍(lán)色。WYK組心肌細(xì)胞形態(tài)正常,結(jié)構(gòu)完整,排列規(guī)則緊湊,細(xì)胞核染色清晰、分布均勻;SHR-SED組心肌細(xì)胞腫脹肥大,排列稀疏并伴有肌纖維斷裂,細(xì)胞核分布雜亂;SHR-MIIT組心肌細(xì)胞較SHR-SED組排列致密有序;SHR-HIIT組心肌細(xì)胞排列更為紊亂、疏松,肌纖維斷裂程度加重或出現(xiàn)融合。
圖3 心肌H&E染色
Figure 3. Myocardial H&E Staining (×400)
與WYK組比較,SHR-SED、SHR-MIIT和SHR-HIIT組均顯著性升高(<0.05),后3組間比較無(wú)顯著性差異(>0.05,圖4)。
圖4 各組心肌細(xì)胞CSA
Figure 4. The CSA of Myocardial Cell in Each Group
注:*<0.05,與WKY組比較。
圖5顯示,心肌細(xì)胞呈紅色,膠原纖維呈藍(lán)色。WYK組心肌肌束間有極少量膠原纖維;SHR-SED組心肌肌束間隙不同程度增大,間質(zhì)可見明顯纖維化改變及膠原沉積;與SHR-SED組比較,SHR-MIIT組纖維化程度明顯減輕,SHR-HIIT組則進(jìn)一步加重。
與WYK組比較,SHR-SED、SHR-MIIT和SHR-HIIT組均顯著性升高(<0.05);與SHR-SED組比較,SHR-MIIT組下降(<0.05),SHR-HIIT組升高(<0.05);與SHR-MIIT組比較,SHR-HIIT組升高(<0.05,圖6)。
圖5 心肌Masson染色
Figure 5. Myocardial Masson Staining (×400)
圖6 各組心臟CVF
Figure 6. Cardiac CVF of Each Group
注:*<0.05,與WKY組比較;#<0.05,與SHR-SED組比較;&<0.05,與SHR-MIIT組比較,下同。
通過(guò)RT-PCR檢測(cè)胚胎基因mRNA表達(dá)量發(fā)現(xiàn)(圖7):與WYK組比較,SHR-SED和SHR-HIIT組ANP、BNP和β-MHC mRNA表達(dá)量均顯著性升高(<0.05);與SHR-SED組比較,SHR-MIIT組各胚胎基因表達(dá)量均下降(<0.05),SHR-HIIT組BNP和β-MHC升高(<0.05);與SHR-MIIT組比較,SHR-HIIT組各胚胎基因均升高(<0.05)。
圖7 各組胚胎基因表達(dá)
Figure 7. Fetal Genes Expression of Each Group
利用Western blot檢測(cè)心臟肥大信號(hào)通路中各蛋白表達(dá)量,結(jié)果發(fā)現(xiàn):
CnAβ:與WYK組比較,SHR-SED和SHR-HIIT組升高(<0.05);與SHR-SED組比較,SHR-MIIT組下降(<0.05),SHR-HIIT組升高(<0.05);與SHR-MIIT組比較,SHR-HIIT組升高(<0.05,圖8)。
圖8 各組CnAβ蛋白表達(dá)量
Figure 8. CnAβ Protein Expression of Each Group
t-NFATc3:t-NFATc3在各組間均無(wú)顯著性差異(>0.05)。t-NFATc3和p-NFATc3/t-NFATc3比值:與WYK組比較,SHR-SED和SHR-HIIT組降低(<0.05);與SHR-SED組比較,SHR-MIIT組升高(<0.05),SHR-HIIT組降低(<0.05);與SHR-MIIT組比較,SHR-HIIT組降低(<0.05,圖9a、圖9b)。
Figure 9. NFATc3 Protein Expression of Each Group
PI3-K(p110α):與WYK組比較,SHR-SED組無(wú)顯著性差異(>0.05),SHR-MIIT和SHR-HIIT組升高(<0.05);與SHR-SED組比較,SHR-MIIT和SHR-HIIT組升高(<0.05);與SHR-MIIT組比較,SHR-HIIT組無(wú)顯著性差異(>0.05,圖10)。
圖10 各組PI3-K(p110α)蛋白表達(dá)量
Figure 10. PI3-K(p110α) Protein Expression of Each Group
t-Akt:t-Akt在各組間均無(wú)顯著性差異(>0.05)。t-Akt和p-Akt/t-Akt比值:與WYK組比較,SHR-SED組無(wú)顯著性差異(>0.05),SHR-MIIT和SHR-HIIT組升高(<0.05);與SHR-SED組比較,SHR-MIIT組和SHR-HIIT組升高(<0.05);與SHR-MIIT組比較,SHR-HIIT組升高(<0.05,圖11a、圖11b)。
Figure 11. Akt Protein Expression of Each Group
與WYK組比較,SHR-SED和SHR-HIIT組腎上腺質(zhì)量指數(shù)增加(<0.05)、胸腺質(zhì)量指數(shù)降低(<0.05);與SHR-SED組比較,SHR-MIIT組腎上腺質(zhì)量指數(shù)下降(<0.05)、胸腺質(zhì)量指數(shù)升高(<0.05),SHR-HIIT組腎上腺質(zhì)量指數(shù)增加(<0.05)、胸腺質(zhì)量指數(shù)降低(<0.05);與SHR-MIIT組比較,SHR-HIIT組腎上腺質(zhì)量指數(shù)增加(<0.05)、胸腺質(zhì)量指數(shù)降低(<0.05,圖12、圖13)。
圖12 各組腎上腺質(zhì)量指數(shù)
Figure 12. Adrenal Mass Index of Each Group
圖13 各組胸腺的質(zhì)量指數(shù)
Figure 13. Thymic Mass Index of Each Group
病理性心臟肥大是高血壓患者最常見的并發(fā)癥和最重要的心血管危險(xiǎn)因素,其嚴(yán)重程度與心血管不良事件(心肌梗塞、心律失常、心力衰竭等)發(fā)生率增加以及預(yù)后不良密切相關(guān)(Shenasa et al.,2017)。在本研究中,SHR-SED組心臟質(zhì)量和心肌細(xì)胞CSA增加、心室壁增厚、心腔容積縮窄,即心臟形態(tài)與結(jié)構(gòu)上發(fā)生向心性肥大。心臟肥大最初對(duì)于過(guò)高的室壁應(yīng)力具有代償作用,有利于增加心肌收縮力以維持心功能,但伴隨高血壓進(jìn)程,肥大的心肌需氧量增加造成心肌缺血,細(xì)胞表型發(fā)生改變,即胚胎基因(ANP、BNP和β-MHC)激活以及心肌纖維化(CVF增加),最終導(dǎo)致心功能下降以及心力衰竭。由于胚胎基因編碼的胎兒型蛋白質(zhì)功能低下,因而造成心臟表型由成熟的“收縮狀態(tài)”向“胚胎型合成狀態(tài)”轉(zhuǎn)變,加之細(xì)胞凋亡使得參與肌肉收縮的心肌細(xì)胞數(shù)量減少,因此心肌收縮力下降(Dzudie et al.,2017)。心肌發(fā)生纖維化則導(dǎo)致心臟硬度增加以及心室壁順應(yīng)性下降(Li et al.,2017),進(jìn)而影響心臟舒縮功能;此外心肌纖維化還可增加心肌電不均一性,易引發(fā)室性心律失常,是心血管疾病患者心源性猝死的重要原因(Nadruz et al.,2015)。
經(jīng)過(guò)18周運(yùn)動(dòng)后,MIIT并未對(duì)心臟質(zhì)量(HM、HMI、LVM和LVMI)和細(xì)胞體積(CSA)產(chǎn)生影響,但心腔容積和室壁厚度成比例增加(LVEDD和LVWT均升高),提示心臟由“向心性肥大”轉(zhuǎn)變?yōu)椤半x心性肥大”,與施曼莉等(施曼莉 等,2015)采用有氧運(yùn)動(dòng)方式干預(yù)心肌梗塞后心力衰竭大鼠的研究結(jié)果類似。由于SHR-MIIT組胚胎基因過(guò)表達(dá)得到抑制(ANP、BMP和β-MHC mRNA下調(diào))、心肌纖維化減輕(CVF下降),同時(shí)血液動(dòng)力學(xué)(血壓下降)和心功能改善(LVEF升高),因此MIIT誘導(dǎo)的心臟“離心性肥大”屬“生理性肥大”。有關(guān)長(zhǎng)跑、游泳等耐力項(xiàng)目運(yùn)動(dòng)員的研究發(fā)現(xiàn)(Lovic et al.,2017),長(zhǎng)期有氧運(yùn)動(dòng)可引起心腔擴(kuò)張、心壁增厚、心臟體積增加,心臟舒縮功能提高,與本研究針對(duì)SHR的結(jié)果基本一致,其機(jī)制與運(yùn)動(dòng)時(shí)容量負(fù)荷(心臟前負(fù)荷)增加造成肌節(jié)串聯(lián)性增生有關(guān)(Bessem et al.,2018)。Xu等(2015)的研究同樣證實(shí),運(yùn)動(dòng)預(yù)適應(yīng)形成的生理性心臟肥大可減輕隨后壓力過(guò)負(fù)荷誘導(dǎo)的病理性心臟肥大以及心力衰竭程度。因此推測(cè),運(yùn)動(dòng)誘導(dǎo)的生理性心臟肥大與高血壓引起的病理性肥大在大鼠MIIT過(guò)程中同時(shí)存在并相互作用,最終前者的有益效應(yīng)抵消了后者的不良影響,心臟由病理性肥大向生理性肥大轉(zhuǎn)變,同時(shí)心功能增強(qiáng)、心力衰竭進(jìn)程得到延緩。
HIIT是一種更具效率的訓(xùn)練模式,據(jù)報(bào)道,3次/周,共2周的HIIT即可改善健康無(wú)訓(xùn)練經(jīng)歷者(Jacobs et al., 2013)、2型糖尿病患者(Little et al.,2014)甚至競(jìng)技運(yùn)動(dòng)員(Christensen et al.,2011)的運(yùn)動(dòng)能力,與有氧運(yùn)動(dòng)產(chǎn)生類似的骨骼肌適應(yīng),然而其對(duì)心臟(尤其是病理狀態(tài)下)的作用尚存在爭(zhēng)議。研究證實(shí),HIIT能夠減輕糖尿病心肌病(Novoa et al.,2017)、肥胖(Hafstad et al.,2013)以及心肌梗塞后心力衰竭大鼠(Lu et al.,2015)病理性心臟肥大并抑制心臟重塑。然而王增喜等(2018)最近的一項(xiàng)研究顯示,健康大鼠HIIT至第6周出現(xiàn)暫時(shí)性病理性心臟肥大及心功能下降,第10周時(shí)恢復(fù);Holloway等(2015)發(fā)現(xiàn),4周HIIT加重高鹽飲食誘導(dǎo)的高血壓大鼠心臟重塑?;谕踉鱿驳龋?018)的結(jié)果,我們提出以下質(zhì)疑:在Holloway等(2015)的研究中,4周HIIT后心臟重塑加重是一過(guò)性變化還是永久性損害?若屬于一過(guò)性,則延長(zhǎng)干預(yù)時(shí)間心臟適應(yīng)不良可得到逆轉(zhuǎn),若屬不可逆,延長(zhǎng)訓(xùn)練周期將進(jìn)一步造成心功能惡化。課題組前期研究發(fā)現(xiàn)(范朋琦 等,2018),8周HIIT能夠抑制SHR病理性心臟肥大并提高心功能,初步支持“一過(guò)性”觀點(diǎn)。然而該研究(范朋琦 等,2018)與Holloway等(2015)在高血壓造模以及HIIT方案等方面存在顯著差異,因此長(zhǎng)期HIIT的效果尚不確定。本研究將運(yùn)動(dòng)時(shí)間延長(zhǎng)至18周(相當(dāng)于人類運(yùn)動(dòng)10年),結(jié)果發(fā)現(xiàn),SHR-HIIT組心臟質(zhì)量增加,形態(tài)學(xué)上雖然同樣發(fā)生離心性肥大,但心腔擴(kuò)張同時(shí)室壁變薄、心肌纖維化加劇,此改變可導(dǎo)致室壁應(yīng)力大幅增加;此外胚胎基因表達(dá)上調(diào)是病理性心臟肥大發(fā)生的重要機(jī)制,同時(shí)也是心力衰竭進(jìn)展與預(yù)后的重要標(biāo)志物(Dirkx et al., 2013)。上述結(jié)果提示,長(zhǎng)期HIIT誘導(dǎo)病理性心臟肥大進(jìn)一步加重并促進(jìn)心力衰竭進(jìn)展,與Holloway等(2015)利用4周HIIT、Schultz等(2007)和黃凱(2015)等采用長(zhǎng)期自主跑輪運(yùn)動(dòng)以及Benito等(2011)讓大鼠進(jìn)行長(zhǎng)期高強(qiáng)度跑臺(tái)運(yùn)動(dòng)的研究結(jié)果一致。結(jié)合課題組前期的研究[即8周HIIT改善SHR心臟重塑(范朋琦 等,2018)]推測(cè),HIIT對(duì)SHR的心臟效應(yīng)存在“一過(guò)性”特點(diǎn)。這一現(xiàn)象可用心臟的代償能力與運(yùn)動(dòng)負(fù)荷的交互作用來(lái)解釋。本研究采用運(yùn)動(dòng)負(fù)荷逐級(jí)遞增的方式制定HIIT方案,前8周負(fù)荷較低、SHR心臟代償能力較強(qiáng),運(yùn)動(dòng)誘導(dǎo)的炎癥反應(yīng)、氧化應(yīng)激、低氧等信號(hào)途徑輕度激活并介導(dǎo)心臟生理性適應(yīng)(Boutcher et al.,2017)。然而運(yùn)動(dòng)僅能延緩而非逆轉(zhuǎn)高血壓心力衰竭進(jìn)程,心臟重塑依然在隱匿中進(jìn)行,心功能較健康大鼠緩慢降低,加之后10周運(yùn)動(dòng)負(fù)荷較大超過(guò)了心臟代償能力,上述信號(hào)途徑持續(xù)激活并產(chǎn)生大量有害物質(zhì)(炎癥因子、自由基等),進(jìn)而發(fā)生適應(yīng)不良(Pingitore et al., 2015)。18周HIIT期間血壓的時(shí)程動(dòng)態(tài)變化表現(xiàn)出的“雙相反應(yīng)”特征(SBP和DBP均先下降后升高)也間接證實(shí)了上述推斷。此外,運(yùn)動(dòng)負(fù)荷過(guò)重可造成動(dòng)物心理應(yīng)激以及腸道菌群失衡(Yuan et al.,2018),后者則是高血壓進(jìn)展的重要原因(Barna et al.,2018)。由此推測(cè),反復(fù)高強(qiáng)度運(yùn)動(dòng)作為慢性應(yīng)激源致使大鼠長(zhǎng)期處于身體和心理的雙重應(yīng)激狀態(tài)中,通過(guò)誘導(dǎo)腸道菌群失衡加重SHR心臟重塑,本研究中SHR-HIIT組出現(xiàn)腎上腺肥大和胸腺萎縮也說(shuō)明了這一點(diǎn)??傊L(zhǎng)期HIIT促進(jìn)SHR心臟重塑并加速心力衰竭進(jìn)程,同時(shí)心血管不良事件以及并發(fā)癥的發(fā)生率將顯著增加。
病理性和生理性心臟肥大在形態(tài)、結(jié)構(gòu)、功能以及細(xì)胞表型存在顯著差異,其根源是不同性質(zhì)刺激源激活細(xì)胞內(nèi)不同信號(hào)轉(zhuǎn)導(dǎo)通路、進(jìn)而誘導(dǎo)不同基因表達(dá)造成的。在本研究中,SHR-SED組CnAβ表達(dá)上調(diào),p-NFATc3/ NFATc3比值下降(表示NFATc3去磷酸化增加),但PI3-K(p110α)和p-Akt/t-Akt比值無(wú)顯著性變化,提示高血壓誘導(dǎo)病理性心臟肥大信號(hào)途徑激活,而生理性途徑并未受影響,與Wilkins等(2004)的結(jié)果一致。
18周運(yùn)動(dòng)后,與SHR-SED組比較,SHR-MIIT組CnAβ蛋白表達(dá)量下調(diào),而p-NFATc3/NFATc3比值增加,說(shuō)明長(zhǎng)期MIIT能夠抑制Cn/NFAT信號(hào)通路,這與Garciarena等(2009)持續(xù)游泳耐力訓(xùn)練(90 min/天,5天/周,共60天)以及賈祁等(2018)中等強(qiáng)度持續(xù)跑臺(tái)運(yùn)動(dòng)(20 m/min,60 min/天,5天/周,共60天)的研究結(jié)果一致。Konhilas等(2006)以肥厚性疾病、Oliveira等(2009)以心力衰竭以及Nicholson等(2013)以缺血-再灌注損傷為模型同樣發(fā)現(xiàn),有氧運(yùn)動(dòng)能夠抑制心肌細(xì)胞內(nèi)NFATc3核移位并降低促肥大基因的表達(dá)量。此外,我們還發(fā)現(xiàn),SHR-MIIT組PI3-K(p110α)和p-Akt/t-Akt比值增加,提示生理性心臟肥大信號(hào)途徑激活,與Miyachi等(2009)、Sagara等(2012)和McMullen等(2007)以游泳運(yùn)動(dòng)方式的研究結(jié)果類似。然而Garciarena等(2009)卻發(fā)現(xiàn),60天游泳運(yùn)動(dòng)對(duì)PI3-K/Akt信號(hào)通路無(wú)明顯影響,可能與干預(yù)時(shí)間較短有關(guān)。動(dòng)物實(shí)驗(yàn)表明(McMullen et al.,2007; Yeves et al., 2018),PI3-K/Akt信號(hào)通路激活對(duì)病理狀態(tài)下的心肌細(xì)胞起保護(hù)作用,激活PI3-K/Akt可通過(guò)阻斷G蛋白偶聯(lián)受體途徑而抑制Cn/NFAT活性,故推測(cè)SHR-MIIT組Cn/NFAT途徑受抑可能是運(yùn)動(dòng)激活PI3-K/Akt引起的間接效應(yīng)。因此,MIIT通過(guò)激活生理性并抑制病理性心臟肥大信號(hào)途徑促使SHR心臟由病理性肥大向生理性肥大轉(zhuǎn)變。
廖興林等(2009)的研究顯示,大鼠反復(fù)力竭運(yùn)動(dòng)后心肌中Cn表達(dá)上調(diào),而Yeves等(2014)則證實(shí)中等強(qiáng)度游泳運(yùn)動(dòng)則對(duì)Cn無(wú)明顯影響,提示Cn對(duì)運(yùn)動(dòng)的應(yīng)答存在強(qiáng)度依賴性。由于HIIT強(qiáng)度明顯高于MIIT,因此誘導(dǎo)Cn/NFAT途徑激活。有趣的是,HIIT同時(shí)又上調(diào)PI3-K/Akt活性,說(shuō)明病理性和生理性信號(hào)途徑同時(shí)被活化,但由于后者的作用無(wú)法代償前者的不良影響,因此最終走向心力衰竭。值得注意的是,SHR-HIIT組PI3-K(p110α)表達(dá)量較SHR-MIIT組無(wú)顯著性差異,但p-Akt/t-Akt卻顯著升高(約3倍),提示尚存在其他上調(diào)Akt的途徑。研究顯示,激活PI3-K/Akt信號(hào)途徑既可誘導(dǎo)生理性(Matsui et al.,2002; Shiojima et al.,2002)又能導(dǎo)致病理性(Condorelli et al.,2002)心臟肥大,其效應(yīng)主要取決于Akt上調(diào)的幅度(O'Neill et al.,2005)。因此推測(cè),Akt過(guò)度激活在HIIT過(guò)程中可能扮演了病理性刺激的角色,與Cn/NFAT途徑協(xié)同作用促進(jìn)病理性心臟重塑進(jìn)一步加劇。
長(zhǎng)期MIIT誘導(dǎo)SHR心臟由病理性肥大向生理性肥大轉(zhuǎn)變并改善心功能,而HIIT則加重心臟重塑并加速心力衰竭進(jìn)程,其機(jī)制與不同強(qiáng)度間歇運(yùn)動(dòng)對(duì)心肌膠原代謝、胚胎基因以及Cn/NFAT和PI3-K/Akt信號(hào)通路的調(diào)控存在差異有關(guān)。
本研究結(jié)果對(duì)于指導(dǎo)高血壓患者運(yùn)動(dòng)康復(fù)具有一定臨床意義。本研究發(fā)現(xiàn),間歇運(yùn)動(dòng)對(duì)高血壓的健康效應(yīng)存在運(yùn)動(dòng)強(qiáng)度依賴性,大強(qiáng)度運(yùn)動(dòng)可能存在一個(gè)安全上限(即“強(qiáng)度閾值”),心血管疾病患者尤其是體適能水平較低者使用HIIT方案應(yīng)持謹(jǐn)慎態(tài)度。由于體適能水平與運(yùn)動(dòng)中心血管不良事件發(fā)生率呈反比(Thompson et al.,2007),故開始HIIT前需要進(jìn)行一段時(shí)間有氧運(yùn)動(dòng)或MIIT作為預(yù)適應(yīng)(Gillen et al., 2014)并加強(qiáng)運(yùn)動(dòng)中的醫(yī)務(wù)監(jiān)督。因此,中等強(qiáng)度運(yùn)動(dòng)(無(wú)論是持續(xù)運(yùn)動(dòng)還是間歇運(yùn)動(dòng))仍然是高血壓患者運(yùn)動(dòng)康復(fù)的最佳方式,HIIT的安全性和有效性則需要更多證據(jù)支持。
范朋琦,秦永生,彭朋,2018.不同運(yùn)動(dòng)方式對(duì)自發(fā)性高血壓大鼠心臟重塑和運(yùn)動(dòng)能力的影響[J].現(xiàn)代預(yù)防醫(yī)學(xué),45(23):4341-4345.
黃凱,彭朋,李曉霞,2015.長(zhǎng)期自主跑輪運(yùn)動(dòng)對(duì)心肌梗死大鼠心肌重塑的影響[J].武警后勤學(xué)院學(xué)報(bào)(醫(yī)學(xué)版),24(5):337-341.
賈祁,李丼,石丼君,等,2018. CaN/NFAT信號(hào)通路在有氧運(yùn)動(dòng)改善高血壓心肌肥大中的作用[J].體育科學(xué),38(12):45-52.
廖興林,常蕓,高曉嶙,等,2009.力竭運(yùn)動(dòng)后不同時(shí)相大鼠心肌CnAβ的變化[J].中國(guó)運(yùn)動(dòng)醫(yī)學(xué)雜志,28(4):388-390.
施曼莉,李曉霞,2015.有氧運(yùn)動(dòng)對(duì)慢性心力衰竭大鼠病理性心臟肥大的影響[J].體育學(xué)刊,22(3):127-134.
王增喜,李潔,王悅,2018.高強(qiáng)度間歇訓(xùn)練對(duì)大鼠心肌線粒體呼吸鏈復(fù)合體活性的影響[J].中國(guó)運(yùn)動(dòng)醫(yī)學(xué)雜志,37(4):315-322.
BARNA I, NYúL D, SZENTES T, et al., 2018. Review of the relation between gut microbiome, metabolic disease and hypertension[J]. Orv Hetil, 159(9): 346-351.
BATACAN R B, DUNCAN M J, DALBO V J, et al., 2016. Light-intensity and high-intensity interval training improve cardiometabolic health in rats[J]. Appl Physiol Nutr Metab, 41(9): 945-952.
BENITO B, GAY-JORDI G, SERRANO-MOLLAR A, et al., 2011. Cardiac arrhythmogenic remodeling in a rat model of long-term intensive exercise training[J]. Circulat, 123(1): 13-22.
BESSEM B, DE BRUIJN M C, NIEUWLAND W, et al., 2018. The electrocardiographic manifestations of athlete's heart and their association with exercise exposure[J]. Eur J Sport Sci, 18(4): 587-593.
BORGES J P, MASSON G S, TIBIRICA E, et al., 2014. Aerobic interval exercise training induces greater reduction in cardiac workload in the recovery period in rats[J]. Arq Bras Cardiol, 102(1): 47-53.
BOUTCHER Y N, BOUTCHER S H, 2017. Exercise intensity and hypertension: what's new?[J]. J Hum Hypertens, 31(3): 157-164.
CHRISTENSEN P M, KRUSTRUP P, GUNNARSSON T P, et al., 2011. VO2 kinetics and performance in soccer players after intense training and inactivity[J]. Med Sci Sports Exerc, 43(9): 1716-1724.
CONDORELLI G, DRUSCO A, STASSI G, et al., 2002. Akt induces enhanced myocardial contractility and cell size in vivo in transgenic mice[J]. Proc Natl Acad Sci, 99(19): 12333-12338.
DIRKX E, DA C M P A, DE WINDT L J, 2013. Regulation of fetal gene expression in heart failure[J]. Biochim Biophys Acta, 1832(12): 2414-2424.
DZUDIE A, DZEKEM B S, KENGNE A P, 2017. NT-pro BNP and plasma-soluble ST2 as promising biomarkers for hypertension, hypertensive heart disease and heart failure in sub-Saharan Africa[J]. Cardiovasc J Afr, 28(6): 406-407.
GARCIARENA C D, PINILLA O A, NOLLY M B, et al., 2009. Endurance training in the spontaneously hypertensive rat: Conversion of pathological into physiological cardiac hypertrophy[J]. Hypertension, 53(4): 708-714.
GILLEN J B, GIBALA M J, 2014. Is high-intensity interval training a time-efficient exercise strategy to improve health and fitness?[J]. Appl Physiol Nutr Metab, 39(3): 409-412.
HAFSTAD A D, LUND J, HADLER-OLSEN E, et al., 2013. High- and moderate-intensity training normalizes ventricular function and mechanoenergetics in mice with diet-induced obesity[J]. Diabetes, 62(7): 2287-2294.
HOLLOWAY T M, BLOEMBERG D, SILVA M L D, et al., 2015. High intensity interval and endurance training have opposing effects on markers of heart failure and cardiac remodeling in hypertensive rats[J]. PLoS One, 10(3): e0121138.
HOYDAL M A, WISLOFF U, KEMI O J, et al., 2007 Running speed and maximal oxygen uptake in rats and mice: Practical implications for exercise training[J]. Eur J Cardiovasc Prev Rehabil, 14(6): 753-760.
HUSSAIN S R, MACALUSO A, PEARSON S J, 2016. High-intensity interval training versus moderate-intensity continuous training in the prevention/management of cardiovascular disease[J]. Cardiol Rev, 24(6): 273-281.
JACOBS R A, FLüCK D, BONNE T C, et al., 2013. Improvements in exercise performance with high-intensity interval training coincide with an increase in skeletal muscle mitochondrial content and function[J]. J Appl Physiol (1985), 115(6): 785-793.
KALETA A M, LEWICKA E, DABROWSKA-KUGACKA A, et al., 2017. Intensive exercise and its effect on the heart: Is more always better?[J]. Cardiol J, 24(2): 111-116.
KONHILAS J P, WATSON P A, MAASS A, et al., 2006. Exercise can prevent and reverse the severity of hypertrophic cardiomyopathy[J]. Circ Res, 98(4): 540-548.
LI S, GUPTE A A, 2017. The role of estrogen in cardiac metabolism and diastolic function[J]. Methodist Debakey Cardiovasc J, 13(1): 4-8.
LITTLE J P, GILLEN J B, PERCIVAL M E, et al., 2011. Low-volume high-intensity interval training reduces hyperglycemia and increases muscle mitochondrial capacity in patients with type 2 diabetes[J]. J Appl Physiol (1985), 111(6): 1554-1560.
LOVIC D, NARAYAN P, PITTARAS A, et al., 2017. Left ventricular hypertrophy in athletes and hypertensive patients[J]. J Clin Hypertens (Greenwich), 19(4): 413-417.
LU K, WANG L, WANG C, et al., 2015. Effects of high-intensity interval versus continuous moderate-intensity aerobic exercise on apoptosis, oxidative stress and metabolism of the infarcted myocardium in a rat model[J]. Mol Med Rep, 12(2): 2374-2382.
MATSUI T, LI L, WU J C, et al., 2002. Phenotypic spectrum caused by transgenic overexpression of activated Akt in the heart[J]. J Biol Chem, 277(25): 22896-22901.
MCMULLEN J R, AMIRAHMADI F, WOODCOCK E A, et al., 2007. Protective effects of exercise and phosphoinositide 3-kinase (p110alpha) signaling in dilated and hypertrophic cardiomyopathy[J]. Proc Natl Acad Sci U S A, 104(2): 612-617.
MIYACHI M, YAZAWA H, FURUKAWA M, et al., 2009. Exercise training alters left ventricular geometry and attenuates heart failure in dahl salt-sensitive hypertensive rats[J]. Hypertension, 53(4): 701-707.
MOUSAVI N, CZARNECKI A, KUMAR K, et al., 2009. Relation of biomarkers and cardiac magnetic resonance imaging after marathon running[J]. Am J Cardiol, 103(10): 1467-1472.
NADRUZ W, 2015. Myocardial remodeling in hypertension[J]. J Hum Hypertens, 29(1): 1-6.
NAKAMURA M, SADOSHIMA J, 2018. Mechanisms of physiological and pathological cardiac hypertrophy[J]. Nat Rev Cardiol, 15(7): 387-407.
NICHOLSON C K, LAMBERT J P, CHOW C W, et al., 2013. Chronic exercise downregulates myocardial myoglobin and attenuates nitrite reductase capacity during ischemia-reperfusion[J]. J Mol Cell Cardiol, 64: 1-10.
NOVOA U, ARAUNA D, MORAN M, et al., 2017. High-intensity exercise reduces cardiac fibrosis and hypertrophy but does not restore the nitroso-redox imbalance in diabetic cardiomyopathy [J/OL]. Oxid Med Cell Longev, https://doi.org/10.1155/2017/ 7921363.
OLIVEIRA R S, FERREIRA J C, GOMES E R, et al., 2009. Cardiac anti-remodelling effect of aerobic training is associated with a reduction in the calcineurin/NFAT signalling pathway in heart failure mice[J]. J Physiol, 587(Pt 15): 3899-3910.
O'NEILL B T, ABEL E D, 2005. Akt1 in the cardiovascular system: friend or foe?[J]. J Clin Invest, 115(8): 2059-2064.
PINGITORE A, LIMA GP, MASTORCI F, et al., 2015. Exercise and oxidative stress: potential effects of antioxidant dietary strategies in sports[J]. Nutrition, 31(7-8): 916-922.
SAGARA S, OSANAI T, ITOH T, et al., 2012. Overexpression of coupling factor 6 attenuates exercise-induced physiological cardiac hypertrophy by inhibiting PI3K/Akt signaling in mice[J]. J Hypertens, 30(4): 778-786.
SCHULTZ R L, SWALLOW J G, WATERS R P, et al., 2007. Effects of excessive long-term exercise on cardiac function and myocyte remodeling in hypertensive heart failure rats[J]. Hypertension, 50(2): 410-416.
SHENASA M, SHENASA H, 2017. Hypertension, left ventricular hypertrophy, and sudden cardiac death[J]. Int J Cardiol, 237: 60-63.
SHIOJIMA I, YEFREMASHVILI M, LUO Z, et al., 2002. Akt signaling mediates postnatal heart growth in response to insulin and nutritional status[J]. J Biol Chem, 277(40): 37670-37677.
SWIFT D L, LAVIE C J, JOHANNSEN N M, et al., 2013. Physical activity, cardiorespiratory fitness, and exercise training in primary and secondary coronary prevention[J]. Circ J, 77(2): 281-292.
THOMPSON P D, FRANKLIN B A, BALADY G J, et al., 2007. Exercise and acute cardiovascular events placing the risks into perspective: A scientific statement from the American Heart Association Council on Nutrition, Physical Activity, and Metabolism and the Council on Clinical Cardiology[J]. Circulation, 115(17): 2358-2368.
WILKINS B J, DAI Y S, BUENO O F, et al., 2004. Calcineurin/NFAT coupling participates in pathological, but not physiological, cardiac hypertrophy[J]. Circ Res, 94(1): 110-118.
XU T, TANG H, ZHANG B, et al., 2015. Exercise preconditioning attenuates pressure overload-induced pathological cardiac hypertrophy[J]. Int J Clin Exp Pathol, 8(1): 530-540.
YEVES A M, BURGOS J I, MEDINA A J, et al., 2018. Cardioprotective role of IGF-1 in the hypertrophied myocardium of the spontaneously hypertensive rats: A key effect on NHE-1 activity[J]. Acta Physiol (Oxf), 224(2): e13092.
YEVES A M, VILLA-ABRILLE M C, PéREZ NG, et al., 2014. Physiological cardiac hypertrophy: Critical role of AKT in the prevention of NHE-1 hyperactivity[J]. J Mol Cell Cardiol, 76: 186-195.
YUAN X, XU S, HUANG H, et al., 2018. Influence of excessive exercise on immunity, metabolism, and gut microbial diversity in an overtraining mice model[J]. Scand J Med Sci Sports, 28(5): 1541-1551.
Interval Training Modulates Pathological Cardiac Hypertrophy in Spontaneously Hypertensive Rats: Relationship between Exercise Intensity and Health Effect
MENG Xianxin1, GUAN Zeyi1, GE Jisheng1, WANG Xiliu1, QIN Yongsheng2, WANG Daning2, PENG Peng2*
: To compare the effects of long-term interval training with different intensities on pathological cardiac hypertrophy in spontaneously hypertensive rats (SHR), and explore the relationship between exercise intensity and health effect.: Forty-five male SHR were randomly divided into a sedentary group (SHR-SED), a moderate-intensity interval training group (SHR-MIIT), or a HIIT group (SHR-HIIT); another fifteen age- and sex- matched Wistar-Kyoto (WYK) rats were set as a normotensive group. Rats in SHR-MIIT and SHR-HIIT groups were performed 18 weeks of MIIT or HIIT training, respectively, and WYK and SHR-SED groups were keep sedentary during experiment. 48 hours after the last training, the caudal artery pressure was measured by using non-invasive blood pressure tester; the cardiac structure and function were detected by using echocardiogram; the myocardial cross sectional area (CSA) and interstitial collagen volumetric fraction (CVF) were obtained by H&E and Masson staining; RT-PCR was used to measure the mRNA levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and β-myosin heavy chain (β-MHC); Western blotting was used to measure the protein levels of calcineurin/nuclear factor of activation T cell (Cn/NFAT) and phosphoinositide 3-kinase/Akt (PI3-K/Akt).: (1) cardiac morphology and structure: the left ventricle was concentric hypertrophy (i.e., cardiac chamber was constricted, ventricular wall was thickened, CSA was increased) and the CVF was increased (<0.05) in SHR-SED group; the left ventricle was eccentric hypertrophy (i.e., cardiac chamber was dilatated, ventricular wall was thickened) and the CVF was reduced (<0.05) in SHR-MIIT group; the SHR-HIIT group was eccentric hypertrophy as well, but the cardiac chamber was dilated and ventricular wall was thinner, the CVF was further increased (<0.05). (2) cardiac function: the left ventricular ejection fraction (LVEF) was decreased (<0.05) in SHR-SED group; the LVEF was raised (<0.05) in SHR-MIIT group but decreased (<0.05) in SHR-HIIT group compared with SHR-SED group. (3) fetal genes expression: the mRNA levels of ANP, BNP and β-MHC was up-regulated (<0.05) in SHR-SED group; compared with SHR-SED group, all genes were down-regulated (<0.05) in SHR-MIIT group while BNP and β-MHC was up-regulated (<0.05) in SHR-HIIT group. (4) protein expression of cardiac hypertrophy: the CnAβ was increased (<0.05) and the p-NFATc3/t-NFATc3 ratio was decreased (<0.05), but the PI3-K(p110α) and p-Akt/t-Akt ratio showed no significant difference (>0.05) in SHR-SED group; compared with SHR-SED group, the CnAβ was reduced (<0.05), and the p-NFATc3/t-NFATc3 ratio, PI3-K(p110α) and p-Akt/t-Akt ratio were raised (<0.05) in SHR-MIIT group; in addition, the CnAβ, PI3-K(p110α) and p-Akt/t-Akt ratio were increased (<0.05), the p-NFATc3/t-NFATc3 ratio was decreased (<0.05) in SHR-HIIT group.: The health effect of long-term interval training on hypertension was dependent on exercise intensity, the MIIT can transform the pathological into physiological hypertrophy to improve the cardiac function, but the HIIT exacerbated cardiac remodeling and accelerate heart failure in SHR. The mechanism was considered to be related to the different regulation of interval training on myocardial collagen metabolism, fetal genes expression as well as the regulation of Cn/NFAT and PI3-K/Akt. Therefore, moderate intensity exercise is still an optimal mode for hypertension patients to rehabilitation in clinical, however, the security and efficiency of HIIT should be further verified.
exercise
2018-07-10;
2019-05-21
天津市自然科學(xué)基金項(xiàng)目(17JCYBJC274002)
孟憲欣(1979-),男,副教授,碩士,主要研究方向?yàn)檫\(yùn)動(dòng)訓(xùn)練與健康促進(jìn), E-mail: mengxianxin1999@126.com。
彭朋(1978-),男,講師,博士,主要研究方向?yàn)檫\(yùn)動(dòng)醫(yī)學(xué), E-mail: doctorpeng2006@126.com。
G804.7
A
1000-677X(2019)06-0073-10
10.16469/j.css.201906009