红芪多糖对ob/ob小鼠肝脂质合成影响

Effect of Hedysarum polybotrys polysacchcaide on lipid synthesis in liver of ob/ob mice

目的研究红芪多糖(HPS)对ob/ob小鼠肝组织固醇调节元件结合蛋白1(SREBP-1)和肝脂质从头合成相关蛋白的影响。方法按照体重将ob/ob雄性小鼠随机分为5组:模型组、阳性药对照组和高、中、低3个剂量实验组,每组10只;将同品系正常C57BL/6野生型雄性小鼠10只作为正常组。阳性药对照组灌胃硫辛酸30 mg·kg^-1·d^-1,高、中、低3个剂量实验组灌胃HPS 200,100,50 mg·kg^-1·d^-1,均连续灌胃8周。以酶联免疫吸附法检测各组小鼠血清总胆固醇(TC)、三酰甘油(TG)、高密度脂蛋白(HDL)和低密度脂蛋白(LDL)含量。用逆转录-PCR法和蛋白质印迹法分别检测肝组织中SREBP-1、乙酰辅酶A羧化酶1(ACC1)、脂肪酸合成酶(FAS)和硬脂酰辅酶A去饱和酶(SCD)基因量(2-△△Ct值)和蛋白的表达。结果正常组、模型组、阳性药对照组和高、中、低3个剂量实验组的TC含量分别为(1.69±0.16),(3.97±0.34),(1.77±0.25),(1.86±0.63),(2.20±0.75)和(3.58±0.25)μmol·L^-1;此6组的TG含量分别为(0.65±0.03),(1.32±0.04),(0.84±0.04),(0.86±0.04),(0.97±0.05)和(1.20±0.03)μmol·L^-1;此6组的LDL含量分别为(0.55±0.13),(1.68±0.21),(0.72±0.28),(0.98±0.15),(1.25±0.23)和(1.47±0.34)μmol·L^-1;此6组的HDL含量分别为(2.05±0.02),(1.15±0.04),(2.00±0.04),(1.98±0.02),(1.63±0.04)和(1.37±0.06)μmol·L^-1;此6组SREBP-1c基因表达量分别为1.00±0.00,1.39±0.02,1.07±0.15,1.03±0.05,1.14±0.04和1.25±0.08;此6组的FAS基因表达量分别为1.00±0.00,1.45±0.10,1.04±0.11,1.07±0.05,1.18±0.05和1.27±0.06;此6组的ACC1基因表达量分别为1.00±0.00,1.27±0.05,1.02±0.12,1.03±0.06,1.11±0.03和1.21±0.04;此6组SCD基因表达量分别为1.00±0.00,1.22±0.08,1.00±0.07,1.01±0.11,1.14±0.04和1.19±0.03。上述指标:模型组与正常组相比,差异均有统计学意义(均P<0.05);阳性药对照组和高、中2个剂量实验组与模型组相比,差异均有统计学意义(均P<0.05)。蛋白表达结果的趋势与基因表达基本一致。结论HPS可能通过调控SREBP-1及其下游肝脂质从头合成关键酶来改善ob/ob小鼠肝脂肪变性。

Objective To study the effects of Hedysarum polybotrys polysacchcaide(HPS)on sterol regulatory element binding protein 1(SREBP-1)in liver and liver lipid synthesis related proteins in ob/ob mice.Methods Male C57 BL/6 ob/ob mice were randomly divided into 5 groups according to weight:model group,positive control group and high,medium,low dose experimental groups with 10 rats in each group;10 non transgenic C57 BL/6 normal male mice were selected as normal group.Mice in positive control group were given lipoic acid 30 mg·kg^-1·d^-1,mice in three doses experimental groups were given HPS 200,100,50 mg·kg^-1·d^-1,all rats were given gavage for 8 weeks.Contents in serum of the total cholesterol(TC),triglycerid(TG),high density lipoprotein(HDL)and low density lipoprotein(LDL)were determined by enzyme linked immunosorbent assay.The mRNA expression(2-△△Ctvalue)and protein expression of sterol regulatory element binding protein 1(SREBP-1),acetyl CoA carboxylase 1(ACC1),fatty acid synthase(FAS)and stearoyl CoA desaturase(SCD)were detected by reverse transcription-PCR and Western blot,respectively.Results The contents of serum TC in normal group,model group,positive control group and high,medium and low dose experimental groups were(1.69±0.16),(3.97±0.34),(1.77±0.25),(1.86±0.63),(2.20±0.75)and(3.58±0.25)μmol·L^-1,respectively;the contents of serum TG in the six groups were(0.65±0.03),(1.32±0.04),(0.84±0.04),(0.86±0.04),(0.97±0.05)and(1.20±0.03)μmol·L^-1,respectively;the contents of serum LDL in the six groups were(0.55±0.13),(1.68±0.21),(0.72±0.28),(0.98±0.15),(1.25±0.23)and(1.47±0.34)μmol·L^-1,respectively;the contents of serum HDL in the six groups were(2.05±0.02),(1.15±0.04),(2.00±0.04),(1.98±0.02),(1.63±0.04)and(1.37±0.06)μmol·L^-1,respectively;the expression of SREBP-1 c gene in the six groups were 1.00±0.00,1.39±0.02,1.07±0.15,1.03±0.05,1.14±0.04 and 1.25±0.08,respectively;the expression of FAS gene in the six groups were 1.00±0.00,1.45±0.10,1.04±0.11,1.07±0.05,1.18±0.05 and 1.27±0.06,respectively;the expression of ACC1 gene in the six groups were 1.00±0.00,1.27±0.05,1.02±0.12,1.03±0.06,1.11±0.03 and1.21±0.04,respectively;the expression of SCD gene in the six groups were 1.00±0.00,1.22±0.08,1.00±0.07,1.01±0.11,1.14±0.04 and 1.19±0.03,respectively.Comparison between model group and normal group,the difference of the above indexes were significant(all P<0.05);comparison between positive control group,high,medium dose experimental groups and model group,the difference of the above indexes were significant(all P<0.05).And the trend of protein expression was basically consistent with gene expression.Conclusion HPS may improve liver steatosis in ob/ob mice by regulating SREBP-1 and its downstream key enzymes of de novo lipogenesis.