壳寡糖对PNPLA3 I148M转基因小鼠肝脏脂质代谢的影响

Effect of chitosan oligosaccharide on hepatic lipid metabolism of PNPLA3 I148M transgenic mice

目的探讨壳寡糖对PNPLA3 I148M转基因小鼠肝脏脂质代谢的影响。方法选取5周龄雄性PNPLA3 I148M转基因小鼠随机分为模型组和壳寡糖组,以同龄C57BL/6J小鼠为对照组。壳寡糖组小鼠每日给予200 mg/kg壳寡糖,模型组及对照组给予等量生理盐水。16周后,Western blot检测小鼠肝脏PNPLA3 I148M的表达。HE和油红O染色观察小鼠肝脏脂质蓄积情况,并测定肝脏甘油三酯(TG)、总胆固醇(TC)含量。同时检测血清中TG、TC、ALT及AST水平。结果模型组及壳寡糖组小鼠肝脏PNPLA3 I148M蛋白表达上调。HE染色示模型组小鼠肝脏发生明显脂肪变性,壳寡糖组小鼠肝细胞内脂肪空泡较少,未见明显脂肪变性;油红O染色示壳寡糖可显著降低转基因小鼠肝细胞内红染脂滴的数量及体积。壳寡糖可减轻PNPLA3I148M基因引起的TG增高,差异有统计学意义(P<0.05);3组小鼠肝脏TC含量差异无统计学意义(P>0.05)。壳寡糖可降低PNPLA3 I148M转基因小鼠血清TG、TC水平,而对ALT和AST水平无影响。结论壳寡糖能减轻PNPLA3 I148M转基因小鼠肝脏脂质沉积,为治疗NAFLD提供新的思路。

Objective To explore the effect of chitosan oligosaccharide（COS） on hepatic lipid metabolism of PNPLA3 I148 M transgenic mice. Methods Five-week-male PNPLA3 I148 M transgenic mice were randomly divided into model group and COS group. The C57BL/6J mice with the same age were selected as control group. The COS group was treated with 200 mg/（kg·d） COS. The same volume of saline was administrated into the other two groups. After 16 weeks, the protein expression of PNPLA3 I148 M in the liver of mice was detected by Western blot. The lipid accumulation of liver was observed by HE and oil red O staining. Triglyceride（TG） and total cholesterol（TC） content in livers were measured. At the same time, serum TG, TC, ALT and AST levels were determined. Results The protein expression of PNPLA3 I148 M in mice livers of model group and COS group was up-regulated. HE staining showed that significant fatty degeneration was observed in livers of model group and few fat vacuoles with no obvious steatosis was found in COS group. Oil red O staining showed COS could significantly reduce the number and volume of lipid droplets in hepatocytes of transgenic mice. COS inhibited the increase of TG induced by PNPLA3 I148 M gene, with significant difference（P〈0.05）. No significant difference was observed on hepatic TC contents among the three groups（P〈0.05）. At the same time, we found COS down-regulated serum TC and TG levels, but had no effects on ALT and AST levels in PNPLA3 I148 M transgenic mice. Conclusions COS can alleviate lipid deposition in the liver of PNPLA3 I148 M transgenic mice, providing a new method for the therapy of non-alcoholic fatty liver disease（NAFLD）.