目的：研究嘌呤生物碱1,3,7,9-四甲基尿酸( theac-rine)对高脂饮食小鼠肝脏甘油三酯蓄积的影响,并进一步探讨其作用机制。方法 C57BL/6J小鼠高脂喂养17周诱导单纯性脂肪肝模型,连续6周给予theacrine后,分别对肝组织切片进行 HE 和苏丹 IV 染色,测定肝脏中甘油三酯(TG)水平,用Western blot 法检测肝脏中SirT3蛋白表达、 AMPK 及ACC 蛋白的磷酸化水平。应用compound C 抑制 HepG2细胞中AMPK 磷酸化,检测theacrine 干预后相关蛋白的表达。结果摇Theacrine 能减少高脂饮食小鼠肝脏中TG 水平,改善肝脏脂肪变性状态,增加肝脏中SirT3蛋白表达及 AMPK 和ACC 蛋白的磷酸化水平。抑制细胞内AMPK 的磷酸化后,theacrine 仍能激活SirT3,但抑制了ACC 的磷酸化作用。结论摇Theacrine 对SirT3的激活不依赖于AMPK 的激活,而对ACC 的磷酸化依赖于AMPK 的激活。其改善高脂饮食小鼠肝脏脂肪化的作用可能与激活SirT3/ AMPK/ ACC 信号通路相关。%Aim To investigate the effects and mecha-nisms of theacrine on high fat diet induced hepatic steatosis in mice. Methods The C57BL/6J mice were fed with high fat diet for consecutive 17 weeks to induce hepatic steatosis and given a treatment of theac-rine for 6 weeks. The liver sections were stained with H&E or Sudan IV, and hepatic TG was determined by commercial analysis kits. Expression of SirT3 and phosphorylation of AMPK and ACC were measured by Western blot. Compound C was used to inhibit the phosphorylation of AMPK in HepG2 cells, and the ex-pressions of proteins were determined after the cells were treated with theacrine. Results Theacrine sig- nificantly decreased hepatic TG content and ameliora-ted hepatic steatosis in mice. Expression of SirT3 and phosphorylation of AMPK and ACC were up-regulated, respectively. And theacrine still could activate SirT3 and up-regulate the phosphorylation of ACC whatever AMPK was inhibited. Conclusions The activation of ACC by theacrine depends on the phosphorylation of AMPK, but the activation of SirT3 by theacrine is in-dependent of the phosphorylation of AMPK. Theacrine ameliorates high fat diet induced hepatic steatosis in mice probably via SirT3/ AMPK/ ACC pathway.
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