李和平 王月影 楊國宇

摘 要：瘤胃酸中毒對瘤胃微生物和代謝產(chǎn)物產(chǎn)生的影響一直備受關(guān)注，但很少有關(guān)于瘤胃酸中毒引起的全身效應(yīng)。高谷物或高脂肪的飲食引起脂多糖（LPS）釋放到胃腸道已涉及反芻動物的脂質(zhì)代謝紊亂。肝臟對入侵的病原體的急性期反應(yīng)起著至關(guān)重要的作用。SARA引起的內(nèi)毒素對肝臟脂質(zhì)代謝的影響尚未明確。選用12只初產(chǎn)薩能奶山羊，隨機(jī)分為對照組和LPS組，每組6只，試驗(yàn)結(jié)束后，采集肝臟組織，利用熒光定量PCR的方法檢測肝臟TLR4信號通路關(guān)鍵分子、脂肪合成和轉(zhuǎn)運(yùn)關(guān)鍵基因的表達(dá)，闡明LPS對奶山羊肝臟脂代謝關(guān)鍵基因表達(dá)的影響，為乳脂肪前體物在肝臟的代謝和重分配研究提供理論依據(jù)。結(jié)果發(fā)現(xiàn)LPS能上調(diào)TLR4、MyD88、IRAK4和NF-κB基因的表達(dá)，下調(diào)LXRα、CD36、VLDLR、APOB、ACC和SCD的表達(dá)，對LXRβ和PPAR的表達(dá)影響不大。提示LPS誘導(dǎo)肝損傷的同時能下調(diào)肝臟脂代謝基因的表達(dá)，進(jìn)而降低肝臟合成與轉(zhuǎn)運(yùn)脂肪的能力。用LPS處理培養(yǎng)的奶牛肝細(xì)胞，發(fā)現(xiàn)LPS處理后肝細(xì)胞由不規(guī)則三角形循環(huán)（收縮）變換，收縮的細(xì)胞數(shù)呈上升趨勢與LPS劑量的增加。提示LPS可促進(jìn)細(xì)胞收縮、脫壁，并最終導(dǎo)致細(xì)胞凋亡，肝細(xì)胞收縮的數(shù)量隨LPS作用時間的延長而增加，利用實(shí)時熒光定量PCR檢測肝細(xì)胞脂質(zhì)代謝的關(guān)鍵酶基因的表達(dá)探討LPS對肝臟脂質(zhì)代謝的影響，結(jié)果發(fā)現(xiàn)，LPS介導(dǎo)的TLR4信號通路可抑制脂肪酸合成基因mRNA的表達(dá)和增加脂肪酸轉(zhuǎn)運(yùn)基因的表達(dá)。

關(guān)鍵詞：LPS 肝臟 奶山羊 奶牛肝細(xì)胞 脂代謝基因

Effects of Rumen Abnormal Metabolite LPS on Apoptosis and Expression of Lipid Metabolism in Liver

Li Heping Wang Yueying Yang Guoyu

（He'nan Agricultural University）

Abstract：The influence of ruminal acidosis on ruminal microbiology and metabolite production has received considerable attention， but less is known about systemic manifestations that arise from ruminal acidosis. The lipopolysaccharides（LPS） released in the gastrointestinal tractduring feeding of high-grain or high-fat diets has beenimplicated in the etiology of multiple energy- and lipidrelatedmetabolic disturbances in ruminants. The liver plays a crucial role in the acute phase response to intruding pathogens.The effect of blood LPS in SARAon lipid metabolism in the liver has not yetbeen established.Twelve primiparity Saanen dairy goats were used in this paper， they were randomly divided into control group and LPS group， six goats each group. After end of experiment， liver tissue were obtained. To clarify the effect ofLPSon the expression of lipid metabolism key genes in liver of dairy goats， providing theorical basis for metabolism and re-distribution of milk fat precursor in liver. The expression of key genes for TLR4 signal pathway， lipid synthesize and transport was detected by fluorescence quantitative PCR methods. The results displayed that LPS could up-regulate the expression of TLR4， MyD88， IRAK4 and NF-κB genes， down-regulate the expression of LXRα， CD36， VLDLR， APOB， ACC and SCD genes， no effect on the expression of LXRβand PPAR genes. It suggested that LPS induced liver injury， and could up-regulate the expression of lipid metabolism genes in liver， and then decreased the ability of lipid synthesize and transport in liver.Cell cultures were observed and photographed using an inverted microscope.The results showed that hepatocytechanged from irregular triangle to circular （contraction） transformation， contractioncell number showed increasing trendwith the increasing doses of LPS. These suggested that LPS can promote cell contraction and take off the wall， and ultimately lead to cellapoptosis， with the time of LPS action， the number ofhepatocytesalso changes. We explored lipid metabolism in the liver by using qRT-PCR to detect lipid metabolism key enzymes gene expression in hepatocytes. We found that TLR4 signaling pathway mediated by LPS canattenuate mRNA expression of fatty acid synthesis genes and increase fat acid transport genes in dairy cow primary hepatocyte following LPS treatment.

Key Words：LPS； Liver； Dairy goat； Dairy cow hepatocyte； Lipid metabolism gene

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