張曉飛　李亞斌　王塬

721001　陜西省寶雞市中醫(yī)醫(yī)院外二科

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·論著·

結直腸癌組織及血紅細胞中多不飽和脂肪酸的分布情況及診斷價值

張曉飛李亞斌王塬

721001陜西省寶雞市中醫(yī)醫(yī)院外二科

【摘要】目的本研究對結直腸癌患者的組織及血液中的多不飽和脂肪酸(PUFA)的含量進行分析，評價PUFA含量在結直腸癌診治中的價值。方法選取2010年3月至2015年3月就診并診斷為結直腸癌的患者共76例，取血保留并于手術中收集其腫瘤組織以及癌周正常組織的標本。分別檢測血紅細胞液中以及腫瘤組織中的PUFA，并計算各脂肪酸成分與總脂酸比值以及ω-6/ω-3 PUFA總比值進行比較分析。結果血紅細胞中LA高于ALA(P<0.01)，AA高于DHA(P<0.01)，總ω-3 PUFA低于ω-6 PUFA(P<0.01)；腫瘤組織中LA高于ALA，AA高于DHA且總ω-3 PUFA低于ω-6 PUFA(P<0.01)；腫瘤組織中LA和總ω-6 PUFA的含量均低于癌周正常組織(P<0.01)，而DPA、DHA和總ω-3 PUFA的含量與癌周正常組織比較顯著增高(P<0.01)；VEGF陽性患者的LA和ω-6 PUFA高于陰性患者(P<0.01)，而P53和Ki-67表達中LA以及總PUFA差異均無統(tǒng)計學意義(P>0.05)。結論多不飽和脂肪酸在體內的分布與腫瘤的發(fā)生密切相關，且可以作為診斷指標具有一定腫瘤診斷價值。

【關鍵詞】結直腸癌；多不飽和脂肪酸；診斷價值

結直腸癌是最常見的惡性腫瘤，發(fā)病年齡趨近于老年化，在我國以年均4.2%的速度增長。其發(fā)病與生活方式、遺傳、大腸腺癌等密切相關，最可控的因素為高脂肪低纖維素飲食的生活方式[1,2]。2000年營養(yǎng)基因組學的提出，引起了科學家對關于機體營養(yǎng)狀態(tài)與腫瘤關系的關注，此學說認為可以通過飲食結構的改變調整基因表達從而調控腫瘤特質，而多不飽和脂肪酸(PUFA)作為機體內可發(fā)揮促進生長發(fā)育、抗心腦血管病以及抗炎、抗癌等重要功能的物質，成為國內外學者的重點突破對象[3,4]。結腸癌與飲食習慣的相關性，為研究PUFA提供了有利條件，而目前內外研究僅聚焦于胃癌、肝癌等細胞水平的實驗，對動物組織分析的研究缺乏清晰認識[5-8]。本研究即通過收集結直腸癌患者的組織及備注對其中PUFA的含量進行分析討論，評價PUFA含量在結直腸癌診治中的價值。

1資料與方法

1.1一般資料選取2010年3月至2015年3月我科就診并診斷為結直腸癌的患者76例，取血保留并于手術中收集其腫瘤組織以及非癌組織的標本。所有患者經術后病理檢查結果證實均為結直腸癌，TNM分期為Ⅰ期10例，Ⅱ期21例，Ⅲ期45例。排除嚴重心肺疾病以及具有結直腸癌家族史患者[9]。

1.2方法進行血液和腫瘤組織中的脂肪酸提取，將血液標本按1∶10加入雙蒸水溶血并離心制成紅細胞液，取50 mg結直腸癌標本置于研缽中，加入液氮研磨成粉狀靜置，收集組織勻漿液進行定量。將兩種細胞液加入1 ml正乙烷和三氟化硼后充分振蕩。將混合物加熱至沸騰持續(xù)1 h，冷卻后加入1 ml去離子水提取上層甲基酯。離心后用200 μl正乙烷干燥樣品并密封利用氣相層析分析儀(GC-1010，日本島津SHIMADZU公司)分析樣品并生成檢測報告。

1.3效果評價分別檢測血紅細胞液中以及腫瘤組織中的PUFA，分別為：(1)ω-3 PUFA：亞麻酸(ALA)、二十碳五烯酸(EPA)、二十二碳五烯酸(DPA)、二十二碳六烯酸(DHA)；(2)ω-6 PUFA：亞油酸(LA)、花生四烯酸(AA)、花生三烯酸(DGLA)、十八碳三烯酸(GLA)。并計算各脂肪酸成分與總脂酸比值以及ω-6/ω-3 PUFA總比值進行比較分析。

2結果

2.1結直腸癌患者血紅細胞及腫瘤組織中PUFA的分布對血紅細胞中各類PUFA的含量進行分析，其LA高于ALA(P<0.01)，AA高于DHA(P<0.01)，總ω-3 PUFA低于ω-6 PUFA(P<0.01)；而腫瘤組織中同樣LA高于ALA，AA高于DHA且總ω-3 PUFA低于ω-6 PUFA(P<0.01)。見表1。

表1　結直腸癌患者血紅細胞及腫瘤組織中PUFA的分布情況　±s

注：與ALA比較，*P<0.05；與DHA比較，#P<0.05；與ω-3 PUFA比較，△P<0.05

2.2結直腸癌患者正常組織與腫瘤組織中PUFA的分布情況對癌周正常組織與腫瘤組織中PUFA的含量進行分析，腫瘤組織中LA和總ω-6 PUFA的含量均低于癌周正常組織(P<0.01)，而DPA、DHA和總ω-3 PUFA的含量與癌周正常組織比較顯著增高(P<0.01)，差異有統(tǒng)計學意義。見表2。

表2　結直腸癌患者癌周正常組織及腫瘤組織中PUFA的分布比較　±s

2.3PUFA含量與結直腸癌患者相關腫瘤因子表達的相關性分析VEGF陽性患者的LA和ω-6 PUFA高于陰性患者(P<0.01)，而P53和Ki-67表達中LA以及總PUFA差異均無統(tǒng)計學意義(P>0.05)。見表3。

表3　PUFA含量與結腸癌患者相關腫瘤因子表達的相關性分析　±s

3討論

多不飽和脂肪酸對人體生理作用的意義重大，ω-3和ω-6系列PUFA在體內有著各自的代謝途徑，但所需酶類為同一酶系，因此在功能上相互協(xié)調制約，存在競爭性抑制作用[10,11]。ω-3能夠抑制體內炎性因子產生和腫瘤血管新生，而ω-6則可促進腫瘤生長。因此兩者的動態(tài)平衡對結直腸癌患者的腫瘤發(fā)生與發(fā)展具有重要意義，本研究即采集結直腸癌患者的血液和腫瘤組織標本進行分析，證明多不飽和脂肪酸在體內的分布與腫瘤的發(fā)生密切相關，且可以作為診斷指標具有一定腫瘤診斷價值[12]。

ω-6 PUFA中的LA通過脫飽和酶的作用產生下游產物DGLA和AA，而兩種組織液中的LA等升高說明此代謝途徑得以加強，抑制了ω-3PUFA的發(fā)生[13,14]。AA及其代謝產物PGE2、TXA2和LTB4等可激活炎性因子釋放，進而細胞惡變以及腫瘤生長和轉移。在本實驗中，血紅細胞和腫瘤細胞的LA均高于ALA，AA高于DHA，總ω-3 PUFA低于ω-6 PUFA。這說明無論在腫瘤內還是患者血液中，ω-6途徑均處于優(yōu)勢地位，這一結論符合現(xiàn)代飲食不均衡造成兩種PUFA失衡的觀點[15,16]。而將腫瘤組織與癌周正常組織進行比較，發(fā)現(xiàn)腫瘤組織中LA和總ω-6 PUFA的含量均低于癌周正常組織，而DPA、DHA和總ω-3 PUFA的含量與正常組織比較顯著增高，此結果說明在腫瘤組織中ω-6 PUFA大量分解成AA進而激活磷脂酶C以及蛋白激酶C等，而癌周正常組織為此代謝途徑提供有力的微環(huán)境，更加有利于結直腸癌患者以ω-6 PUFA為主的脂肪代謝順利進行，同樣ω-3代謝途徑被嚴重抑制，炎性因子被釋放促進腫瘤血管新生誘發(fā)轉移。

PUFA不僅可以通過前列腺素等介導不同癌癥的病理發(fā)展過程，還可以干擾細胞信號通路以及基因表達過程，因此與體內相關腫瘤發(fā)生因子的表達具有重要關系[17, 18]。血管內皮生長因子(VEGF)參與腫瘤的浸潤、轉移，是結直腸癌新生血管的最重要因子之一[19-21]。在本實驗中我們將VEGF的陽性和陰性腫瘤患者的PUFA分別進行分析，發(fā)現(xiàn)其與LA的含量以及ω-6 PUFA的含量具有重要關系，在VEGF陽性患者中兩者的比例明顯升高，說明PUFA在某種程度上可以提示結直腸癌的發(fā)生，證明了其在機體中促腫瘤與抗腫瘤的平衡在代謝中的作用。而在Ki-67和P53陽性的患者中各種表達程度的腫瘤標志因子與多不飽和脂肪酸含量無明顯差異。

綜上所述，PUFA在結直腸癌的發(fā)生發(fā)展中起重要的調節(jié)作用，ω-3和ω-6兩族PUFA的失衡會影響脂肪酸的代謝為炎性反應以及腫瘤生長因子的釋放提供有利條件。因此應注重結直腸癌患者的飲食方式和營養(yǎng)攝入，減少飲食中油脂比較，增加蔬菜水果以及纖維素的吸收，并盡可能的多食深海魚類，補充EPA和DHA可對結直腸癌的預防和治療起到重要作用。

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The distribution and diagnostic value of polyunsaturated fatty acids in red blood cells and colorectal cancer tissues

ZHANGXiaofei,LIYabin,WANGYuan.

TheSecondDepartmentofSurgery,ChineseMedicineHospitalofBaojiCity,Shanxi,Baoji721001,China

【Abstract】ObjectiveTo analyze the distribution of polyunsaturated fatty acids (PUFA) in red blood cells and colorectal cancer tissues in order to evaluate the diagnostic value of PUFA in colorectal cancer .MethodsA total of 76 patients who were diagnosed as colorectal cancer in Department of General Surgery of Baoji TCM Hospital from March 2013 to March 2015 were enrolled in the study. The patients’blood specimens, cancer tissues and normal tissues around the cancer were collected. The contents of PUFA in red blood cells and tumor tissues were detected, and the ratio of fatty acid compositions/total fatty acid as well as the total ratio of ω-6/ω-3 PUFA were calculated and analyzed.ResultsThe levels of LA in red cells were significantly higher than those of ALA (P<0.01), the contents of AA were obviously higher than those of DHA (P<0.01), and total ω-3 PUFA levels were significantly lower than those of ω-6 PUFA (P<0.01). The contents of LA in tumor tissues were significantly higher than those of ALA,furthermore, the levels of AA were obviously higher than those of DHA,however, the levels of ω-3 PUFA were significantly lower than those of ω-6 PUFA (P<0.01). Moreover the contents of LA and ω-6 in tumor tissues were significantly lower than those in normal tissues around cancer (P<0.01), however, the contents of DPA, DHA and total ω-3 PUFA were significantly increased,as compared with those in normal tissues around cancer (P<0.01) The levels of LA and ω-6 PUFA in VEGF positive patients were significantly higher than those of patients with negative VEGF (P<0.01),but there were no significant differences in the expression levels of P53 and Ki-67 between LA and total PUFA (P>0.05).Conclusion The distribution of polyunsaturated fatty acids in the body is closely related to the pathogenesis of cancer,thus,which plays an important role in the diagnosis of cancer.

【Key words】colorectal cancer; polyunsaturated fatty acids; diagnostic value

(收稿日期：2015-06-06)

【中圖分類號】R 735.37

【文獻標識碼】A

【文章編號】1002-7386(2016)10-1478-03

doi:10.3969/j.issn.1002-7386.2016.10.010