CYP1B1基因敲除对成年小鼠肝脏脂肪代谢的影响及可能机制

目的探讨CYP1B1对高脂膳食诱导的成年小鼠脂肪代谢的作用。方法 CYP1B1基因敲除(KO)和野生型(WT)雄性成年C57/BL小鼠(6 w龄)各16只,给予低脂(LFD,30%)、高脂肪(HFD,60%)饲料共6 w。小鼠处死后取血清、附睾脂肪和肝脏组织检测相应的生化和分子生物学指标。结果 6 w高脂膳食后,KO小鼠能量摄入总量稍高于WT小鼠,但其体重增量和附睾脂肪组织重量均显著低于WT小鼠;WT小鼠脂肪细胞直径明显大于KO小鼠,且血糖、血清及肝脏组织中甘油三酯(TG)水平亦明显高于KO小鼠;肝脏组织RT-PCR结果显示,CYP1B1基因敲除后,启动脂肪形成的核因子及脂肪合成相关基因如CD36、SREBP1c、SCD1等表达下降,而调控脂肪氧化分解的基因如CPT-1α,UCP-2表达显著上升;蛋白印迹结果显示,CYP1B1基因敲除增强腺苷-磷酸激酶(AMPK)的磷酸化。结论 CYP1B1基因敲除对成年小鼠营养性肥胖的保护作用可能与AMPK磷酸化增强并调控肝脏中脂肪代谢相关基因的表达有关。

ROLE OF CYP1B1 IN HEPATIC LIPID METABOLISM OF ADULT MICE AND ITS POSSIBLE MECHANISM

Objective To investigate the role of CYP1B1 in lipid metabolism in adult mice.Methods Sixteen male CYP1B1 knock-out mice(KO) and sixteen wild type mice(WT,C57/BL,6-w-old) were both randomly divided into low-fat-diet(LFD,10% fat) and high-–fat-diet(HFD,60% fat) groups for a period of 6 w feeding.The body weight and food consumption were recorded every 3 d.The mice were scarified by decapitation at 12 w age,and the blood was collected for serum analysis.The liver and epididymal fat pad were quickly removed and part of the tissues was frozen in dry ice for RNA extraction,and part of the tissues was fixed in 4% PFA for sectioning.Results With 6 w feeding,HFD significantly increased the body weight and epididymal fat pad weights in WT group and CYP1B1 deletion significantly suppressed these changes.Serum triglyceride(TG) contents and HE staining also showed the same trends.Hepatic genes expression indicated that CYP1B1 deletion suppressed a set of genes expression which was involved in fatty acid synthesis such as CD36、SCD1 and SREBP1c,and enhanced CPT1α,UCP-2 expressions.which were involved in fatty acid beta oxidation.Conclusion CYP1B1 deletion may prevent adult mice from HFD-induced obesity through adenosine monophosphate kinase(AMPK) activation,which regulates downstream hepatic lipid metabolic genes expression.