虾青素对高脂HepG2细胞及高脂膳食饲喂C57BL/6J小鼠血脂代谢的影响

Effect of Astaxanthin on Lipid Metabolism in HepG2 Cells and in C57BL/6J Mice Fed with High-Fat Diet

为研究虾青素对油酸诱导高脂HepG2细胞及高脂膳食饲喂C57BL/6J小鼠血脂代谢的影响。本实验建立油酸诱导HepG2细胞脂肪堆积体外模型,采用油红O对胞内脂滴染色测定脂滴含量,同时测定正常组、高脂组及虾青素组细胞内甘油三酯(triglyceride,TG)、总胆固醇(total cholesterol,TC)浓度。通过高脂膳食饲喂C57BL/6J小鼠,测定正常组、高脂组及虾青素干预组小鼠血清中TC、TG及高密度脂蛋白胆固醇水平;苏木精和伊红染色观察肝组织形态学变化;应用实时荧光定量聚合酶链式反应检测肝脏中脂肪调控相关基因mRNA表达水平;应用气相色谱检测粪便中短链脂肪酸的排泄量。结果表明:虾青素能够显著抑制油酸诱导的HepG2细胞脂肪堆积,显著降低胞内TG、TC浓度(P<0.05);与高脂组相比,给予虾青素后,小鼠的TC和TG水平均显著降低(P<0.05);苏木精和伊红染色结果表明虾青素干预组脂肪变性程度明显减轻;同时虾青素干预后总短链脂肪酸的含量显著增加,且肝脏中脂肪合成相关基因SREBP-1C和FAS表达水平显著下调(P<0.05)。结论:虾青素通过降低HepG2细胞中脂滴含量、调节血脂水平、提高粪便中短链脂肪酸的含量,改善肝脏病理状态,调控肝脏中脂肪合成相关基因的表达,对血脂代谢起到调节作用。

This study aims to evaluate the effects of astaxanthin on lipid metabolism in HepG2 cells treated with oleic acid and in C57BL/6J mice fed with a high-fat diet.A HepG2 cell model of oleic acid-induced steatosis in vitro was established.Furthermore,cellular lipid accumulation was determined using Oil red O staining assay and cholesterol(TC),triglyceride(TG)contents were determined in the normal,model and astaxanthin treatment groups.Serum total TC,TG and high-density-lipoprotein-cholesterol(HDL-C)of mice in the normal diet,high-fat and astaxanthin intervention groups were detected as well.Liver histomorphology was observed by hematoxylin and eosin(HE)staining.The mRNA expression levels of the genes related to lipid regulation were determined using quantitative real-time polymerase chain reaction(qRT-PCR).The fecal excretion of short chain fatty acids was detected by gas chromatography(GC).Astaxanthin could significantly alleviate oleic acid-induced steatosis in HepG2 cells,and cellular TC and TG contents decreased significantly in the astaxanthin intervention group compared with the model group(P<0.05).Furthermore,the SREBP-1C and FAS mRNA expression levels were significantly down-regulated in the astaxanthin intervention group,the degree of steatosis in the astaxanthin intervention group was significantly decreased and the content of total short-chain fatty acids increased significantly,and serum TG and TC levels decreased significantly relative to those in the high-fat diet group(P<0.05).Therefore,Astaxanthin can regulate lipid metabolism by reducing the content of lipid droplets in HepG2 cells,and by regulating blood lipid levels,increasing the content of short-chain fatty acids in feces,improving liver pathology,and regulating the expression of the genes related to lipid synthesis in the liver of mice.