Institute of Toxicology, School of Public Health, Shandong University, Jinan City, Shandong Province, People's Republic of China.
PLoS One. 2014 Jun 3;9(6):e98658. doi: 10.1371/journal.pone.0098658. eCollection 2014.
Cytochrome P4502E1 (CYP2E1) has been suggested to play critical roles in the pathogenesis of alcoholic fatty liver (AFL), but the underlying mechanisms remains unclear. The current study was designed to evaluate whether CYP2E1 suppression by chlormethiazole (CMZ) could suppress AFL in mice, and to explore the underlying mechanisms.
Mice were treated with or without CMZ (50 mg/kg bw, i.p.) and subjected to liquid diet with or without ethanol (5%, w/v) for 4 weeks. Biochemical parameters were measured using commercial kits. The protein and mRNA levels were detected by western blot and qPCR, respectively. Histopathology and immunohistochemical assay were performed with routine methods.
CYP2E1 inhibition by CMZ completely blocked AFL in mice, shown as the decline of the hepatic and serum triglyceride levels, and the fewer fat droplets in the liver sections. Chronic ethanol exposure led to significant decrease of the mRNA and protein levels of peroxisome proliferator-activated receptor α (PPAR-α), which was blocked by CMZ co-treatment. CMZ co-treatment suppressed ethanol-induced oxidative stress, overproduction of tumor necrosis α (TNF-α), and decrease of protein levels of the PPAR-α co-activators including p300 and deacetylated PGC1-α. Furthermore, CMZ co-treatment led to the activation of AMP-activated protein kinase (AMPK), mitogen-activated protein kinase (MAPK), and PI3K/Akt/GSK3β pathway. However, chronic ethanol-induced decline of acyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) protein levels was partially restored by CMZ, while the activation of autophagy appeared to be suppressed by CMZ.
These results suggested that CMZ suppressed chronic ethanol-induced oxidative stress, TNF-α overproduction, decline of p300 protein level and deacetylation of PGC1-α, and activated AMPK, MAPK, and PI3K/Akt/GSK3β pathway, which might contribute to the activation of PPAR-α and account for the protection of CMZ against AFL.
细胞色素 P4502E1（CYP2E1）被认为在酒精性脂肪肝（AFL）的发病机制中起关键作用，但潜在机制尚不清楚。本研究旨在评估氯美噻唑（CMZ）是否通过抑制 CYP2E1 来抑制小鼠的 AFL，并探讨其潜在机制。
用或不用 CMZ（50mg/kg bw，腹腔注射）处理小鼠，并接受含或不含乙醇（5%，w/v）的液体饮食 4 周。使用商业试剂盒测量生化参数。通过 Western blot 和 qPCR 分别检测蛋白和 mRNA 水平。采用常规方法进行组织病理学和免疫组织化学检测。
CMZ 抑制 CYP2E1 可完全阻断小鼠的 AFL，表现为肝和血清甘油三酯水平下降，肝切片中的脂肪滴减少。慢性乙醇暴露导致过氧化物酶体增殖物激活受体α（PPAR-α）的 mRNA 和蛋白水平显著下降，CMZ 共同处理可阻断这种下降。CMZ 共同处理抑制了乙醇诱导的氧化应激、肿瘤坏死因子-α（TNF-α）的过度产生以及 PPAR-α 共激活剂（包括 p300 和去乙酰化 PGC1-α）的蛋白水平下降。此外，CMZ 共同处理导致 AMP 激活蛋白激酶（AMPK）、丝裂原激活蛋白激酶（MAPK）和 PI3K/Akt/GSK3β 通路的激活。然而，CMZ 部分恢复了慢性乙醇诱导的乙酰辅酶 A 羧化酶（ACC）和脂肪酸合成酶（FAS）蛋白水平的下降，而自噬的激活似乎被 CMZ 抑制。
这些结果表明，CMZ 抑制了慢性乙醇诱导的氧化应激、TNF-α过度产生、p300 蛋白水平下降和 PGC1-α去乙酰化，激活了 AMPK、MAPK 和 PI3K/Akt/GSK3β 通路，这可能有助于激活 PPAR-α，并解释了 CMZ 对 AFL 的保护作用。
