[Study of the effect of CHOP signaling molecule in PPARα activation and inhibition with response to inflammation in mice with acute liver failure]

Objective: To investigate the mechanism of action of peroxisome proliferator-activated receptor α (PPARα)-mediated CCAAT/enhancer binding protein homologous protein (CHOP) signaling molecule with response to inflammation in mice with acute liver failure. Methods: C57BL/6 mice were used as the research subjects, and D-galactose (D-GalN) combined with lipopolysaccharide (LPS) was injected intraperitoneally to establish a mouse model of acute liver failure. PPARα was activated by Wy-14643. CHOP expression was promoted by plasmids. Liver pathological changes and serum transaminases (ALT and AST) were detected in mice to evaluate liver function. The mRNA expression level of inflammatory factors in liver tissue was detected by real-time fluorescence quantitative PCR. LPS-stimulated macrophage was used to establish an inflammation model. PPARα and CHOP expression was inhibited by siRNA. The mRNA expression level of inflammatory factors in the cells was detected by real-time fluorescence quantitative PCR. Results: Promoted PPARα activation had inhibited liver hemorrhage and inflammation in mice with acute liver failure induced by D-GalN/LPS. In addition, the serum level of transaminases and genetic level of inflammatory factors in liver tissues were reduced (P < 0.01). CHOP accelerated expression had reversed the hepatoprotective effect of PPARα activation, aggravated liver injury, and increased inflammatory factors expression (P < 0.01). At the cellular level, the inhibition of PPARα activation had accelerated the increase of inflammatory factors (P < 0.01), while the inhibition of CHOP activation had all over again decreased the inflammatory factors (P < 0.01). Conclusion: PPARα and CHOP are important signaling molecules to regulate the inflammatory response in acute liver failure and liver injury. PPARα acceleration can down-regulate CHOP to inhibit inflammatory factors, which might play a protective role in mice with acute liver failure.

目的： 探讨过氧化物酶体增殖物激活受体α（PPARα）介导CCAAT/增强子结合蛋白同源蛋白（CHOP）信号分子在急性肝衰竭小鼠炎症反应中的作用机制。 方法： 以C57BL/6小鼠为研究对象，腹腔注射D-氨基半乳糖（D-GalN）联合脂多糖（LPS）建立小鼠急性肝衰竭模型。用Wy-14643激活PPARα、用质粒促进CHOP表达，检测小鼠肝脏病理改变、血清丙氨酸转氨酶（ALT）、天冬氨酸转氨酯（AST）评价肝脏功能，实时荧光定量PCR检测肝组织中炎性因子mRNA表达水平。LPS刺激巨噬细胞建立炎症模型，用siRNA抑制PPARα、CHOP的表达，实时荧光定量PCR检测细胞中炎性因子mRNA表达水平。 结果： D-GalN/LPS诱导急性肝衰竭小鼠中，促进PPARα活性抑制了小鼠肝脏出血和炎症，降低了血清转氨酶水平，也降低了肝组织中炎症因子的mRNA水平（P < 0.01）。促进CHOP表达，逆转了PPARα激活带来的肝脏保护作用，肝脏损伤加重，炎症因子表达增加（P < 0.01）。细胞水平上，PPARα活性抑制促进了炎症因子的增高（P < 0.01），同时抑制CHOP活性后使炎症因子重新下降（P < 0.01）。 结论： 急性肝衰竭肝损伤中PPARα和CHOP分子是调节炎症反应的重要信号分子，促进PPARα可下调CHOP抑制炎症因子发挥对小鼠肝衰竭的保护性作用。.

Keywords: Acute liver failure; C/EBP homologous protein; Inflammation; Peroxisome proliferator-activated receptor alpha.