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目的在长程高脂膳食诱导的脂肪肝小鼠中,探讨白介素17A(interleukin 17A,IL-17A)基因缺陷对脂多糖(lipopolysaccharide,LPS)诱导的急性肝损伤的作用及其可能的机制。方法利用IL-17A基因敲除小鼠构建脂肪肝急性损伤模型,通过检测血浆中谷丙转氨酶(alanine transaminase,ALT)和谷草转氨酶(aspartate transaminase,AST)评估肝脏损伤情况,通过检测血浆中3种主要炎症因子TNF-α、IL-1β以及IL-6评估机体炎症水平,通过肝脏病理形态观测肝脏组织炎症细胞浸润和肝细胞损伤情况。通过对肝脏组织表达mRNA进行转录组学分析,寻找IL-17A基因敲除在高脂膳食(high fat diet,HF)+LPS诱导的肝损伤中的发挥作用的相关分子信号机制。结果在高脂膳食喂养辅之以一次性LPS刺激下,IL-17A基因敲除(gene knockout,KO)小鼠血浆中的ALT及AST水平显著降低(P<0.05);KO小鼠血浆中炎症因子水平显著降低(P<0.05),肝脏组织中浸润的炎症细胞显著减少(P<0.05)。肝脏转录组学分析结果显示,刺激后,KO小鼠下调的938个基因主要富集于氧化应激(P<0.01)、过氧化氢代谢途径(P<0.01)以及谷胱甘肽代谢途径(P<0.01)。Real-time PCR检测发现KO小鼠肝脏中与过氧化氢代谢相关的CAT、GPX1、IDH1、IDH2以及ME1基因的mRNA水平显著升高。同时,肝脏的氧化应激水平显著降低(P<0.05)。TUNEL检测进一步检测结果显示,KO小鼠肝脏凋亡细胞数量显著减少(P<0.01)。结论 IL-17A基因敲除可能通过促进过氧化氢代谢减轻LPS诱导的脂肪肝小鼠急性炎症性肝损伤。
Objective To investigate the effect of interleukin 17A (IL-17A) gene defect on acute hepatic injury induced by lipopolysaccharide (LPS) and its possible mechanism in fatty liver mice induced by long-term and high fat diet. Methods The acute injury model of fatty liver was constructed by IL-17A knockout mice. The liver injury was evaluated by detecting plasma alanine transaminase (ALT) and aspartate transaminase (AST), and the plasma levels of three main Inflammatory cytokines TNF-α, IL-1β and IL-6 were used to evaluate the level of inflammation in the body. Inflammatory cytokines and hepatocyte damage were observed by histopathology. To investigate the molecular mechanism of IL-17A gene knockdown in liver injury induced by high fat diet (HF) + LPS by transcriptomic analysis of mRNA expression in liver tissues. Results The levels of ALT and AST in the plasma of IL-17A gene knockout (KO) mice were significantly decreased (P <0.05) with high-fat diet supplemented with one-time LPS stimulation. The plasma levels of inflammation (P <0.05). Inflammatory cells infiltrated in the liver were significantly decreased (P <0.05). Hepatic transcriptomics analysis showed that 938 genes of KO mice were mainly enriched in oxidative stress (P <0.01), hydrogen peroxide (P <0.01) and glutathione metabolism P <0.01). Real-time PCR showed that mRNA levels of CAT, GPX1, IDH1, IDH2, and ME1 genes associated with hydrogen peroxide metabolism in the liver of KO mice were significantly elevated. Meanwhile, the level of oxidative stress in liver decreased significantly (P <0.05). TUNEL test further test results showed that KO mice liver apoptotic cells significantly reduced (P <0.01). Conclusion IL-17A knockout may reduce acute inflammatory liver injury induced by LPS in fatty liver mice by promoting hydrogen peroxide metabolism.