右美托咪定抑制肝细胞脂质累积的作用及机制研究

Effect of dexmedetomidine against lipid accumulation in hepatocytes and related mechanism

摘要:

目的 探讨右美托咪定（dexmedetomidine，DEX）对肝细胞脂质代谢过程的调控作用及可能机制。方法 分离小鼠原代肝脏细胞，用游离脂肪酸处理24 h构建肝细胞脂质累积模型，分别用浓度200 ng/mL，500 ng/mL和1 000 ng/mL的DEX药物处理原代肝脏细胞24 h。收集细胞进行油红O染色观察细胞中脂质累积情况；通过实时荧光定量PCR和免疫印迹技术检测细胞脂质代谢关键基因的表达情况；通过实时荧光定量PCR检测DEX处理不同作用时间点α_2A-肾上腺素受体的表达变化情况；进一步通过免疫印迹技术探究DEX对相关信号通路蛋白表达的影响。结果 不同浓度DEX药物处理原代肝脏细胞后，细胞中脂质累积明显减少，且呈剂量依赖性。与脂肪酸和甘油三酯合成的关键基因如脂肪酸合成酶、硬脂酰辅酶A去饱和酶1及过氧化物酶体增殖物激活受体γ的表达显著被抑制（P<0.05）；α_2A-肾上腺素受体的表达先升高后被抑制；DEX药物可显著降低原代肝脏细胞P65和P38的磷酸化水平（P<0.05）。结论 DEX可减轻肝脏细胞脂质累积，其机制可能与细胞α_2A-肾上腺素受体和MAPK/NF-κB信号通路被抑制有关。

Abstract:

Objective To investigate the regulatory effect of dexmedetomidine（DEX） on lipid metabolism in hepatocytes and the underlying mechanism.Methods Primary mouse hepatocytes were isolated and then treated with free fatty acids for 24 hours to establish a hepatocyte lipid accumulation model. Primary hepatocytes were treated with DEX separately at concentrations of 200 ng/mL，500 ng/mL，and 1 000 ng/mL for 24 hours，and then were collected for Oil Red O staining to observe the level of lipid accumulation. The expression levels of key lipid metabolism genes in hepatocytes were determined by real-time quantitative PCR and Western blot. The expression of α_2A-adrenoceptors at different time points of DEX treatment was measured by real-time quantitative PCR. The protein expression of associated signaling pathways was determined by Western blot.Results The level of lipid accumulation in primary hepatocytes was significantly reduced after treatment with DEX in a dose-dependent manner. The expression levels of key genes related to fatty acid and triglyceride synthesis（including fatty acid synthase，stearoyl-coenzyme A desaturase 1，and peroxisome proliferator-activated receptor γ） were significantly inhibited（P<0.05）. The expression of α_2A-adrenoceptors was firstly increased and then inhibited. In addition，DEX significantly decreased the phosphorylation levels of P65 and P38 in primary hepatocytes（P<0.05）.Conclusion DEX can reduce lipid accumulation in the liver，which may be related to the activation of α_2A-adrenoceptors and the MAPK/NF-κB signaling pathway.