围产期高脂高糖孕鼠NP暴露对仔鼠肥胖的影响及机制探讨

摘要

目的 观察围产期高脂高糖孕鼠壬基酚(NP)暴露对子代体质量、脂肪生成及脂肪细胞分化基因、肝脏和脂肪细胞变化的影响,探讨在围产期高脂高糖饮食基础上NP暴露对仔鼠肥胖的作用机制.方法 选择SD大鼠雌性40只、雄性20只合笼交配,收集交配成功的孕鼠,随机分为普通饲料对照组(OC组)、高脂高糖饲料对照组(HC组)、高脂高糖饲料+NP低剂量组(HNL组)、高脂高糖饲料+NP高剂量组(HNH组)各10只.普料OC组食用普通饲料,HC组、HNL组、HNH组均食用高脂高糖饲料.从母鼠受孕第6天到产后第21天,OC组、HC组孕鼠均予玉米油0.5 mL/(kg·d)灌胃,HNL组、HNH组分别予NP 50、100 mg/(kg·d)灌胃.仔鼠出生后正常进行母乳喂养,断乳后均以普通饲料喂养至70 d.干预70 d后,取仔鼠腹主动脉血,采用全自动生化分析仪检测血清TG、TC、HDL及LDL水平.取血前称仔鼠体质量,取血后取性腺旁脂肪垫测脂肪质量,计算脂肪系数.取仔鼠肝脏组织,采用Real Time PCR法检测调控脂肪细胞分化的关键基因转录调节因子(CEBP-α)、固醇调节结合蛋白(SREBP-1)、过氧化物酶体增殖物激活受体γ(PPARγ)mRNA的表达.取仔鼠肝脏组织和性腺旁脂肪组织,采用HE染色法观察肝脏细胞和脂肪细胞形态.结果 HNL组、HNH组血清TG、TC、LDL均高于HC组(P均<0.01).HNL组、HNH组体质量、脂肪系数均高于HC组,HNH组脂肪质量高于HC组(P均<0.01).HNH组CEBP-α mRNA表达高于OC组(P<0.01).HNH组的SREBP-1、PPARγ mRNA表达均高于HC组(P均<0.01).HE染色示,HC组可见部分肝脏细胞脂肪变性,HNL组可见大量肝细胞脂肪样变,HNL组可见肝细胞广泛气球样变和大量脂滴;HC组部分脂肪细胞面积增大,HNL组大部分脂肪细胞面积明显增大.结论 围产期高脂高糖孕鼠NP联合暴露可增加仔鼠体质量、脂肪质量、血脂含量,导致肝脏脂肪样和脂肪细胞增大增多,其机制可能是NP导致脂肪细胞分化基因CEBP-α、SREBP-1、PPARγ表达异常有关.%Objective To observe the effect of nonylphenol (NP) exposure on offspring weight,fat generation and adipocyte differentiation genes,liver and adipocyte changes of pregnant rats induced by high-fat and high-sugar diet during perinatal period and to explore the mechanism of offspring obese occurrence via high-fat and high-glucose diet treatment combined with NP exposure in perinatal mothers.Methods Forty female SD rats were mated with 20 male SD rats.Then we collected the pregnant rats and divided them into the ordinary diet control group (OC),The high fat diet control group (HC),high fat+low-dose Nonylphenol group (HNL),and high fat + high-dose Nonylphenol group (HNH).Rats in the OC grup were fed with normal diet,and rats in the HC,HNL and HNH groups were fed with high fat and high sugar diet.Pregnant rats were given gestational gavage from day 6 to postpartum 21 days.In the OC group and HC group,the pregnant rats were given 0.5 mL/(kg·d) corn oil,in the HNL group and HNH,they were given NP 50,100 mg/(kg·d) by gavage.Pregnant rats were fed with normal breast feeding and fed with normal diet for up to 70 days after birth.After 70 days of intervention,the blood of the abdominal aorta of the offspring was taken and the levels of serum TG,TC,HDL and LDL were measured by automatic biochemical analyzer.Before taking blood,we measured the weight of offspring rats.After taking the blood,we took the gonadal fat pad to measure fat quality and calculate the fat coefficient.We collected the liver tissues of the offsprings,Using real-time PCR to detect the regulation of adipocyte differentiation key gene transcription factor (CEBP-α),sterol regulatory binding protein (SREBP-1),peroxisome proliferator-activated receptor γ (PPARγ) mRNA expression.Liver tissues and adipose tissues were observed by HE staining.Results The levels of serum TG,TC and LDL in the HNL group and HNH group were higher than those in the HC group (all P<0.01).The body mass and fat coefficient of the HNL group and HNH group were higher than those of the HC group,and the fat quality of the HNH group was higher than that of the HC group (all P<0.01).The expression of CEBP-α mRNA in the HNH group was higher than that in the OC group (P<0.01).The expression of SREBP-1 and PPARγ mRNA in the HNH group was higher than that in the HC group (all P<0.01).HE staining showed that some liver cells were steatosis in the HC group,and a large number of hepatocyte fat-like changes were seen in the HNL group.The extensive balloon-like and large amount of lipid droplets were found in the HNL group.In the HC group,part of the fat cell area increased,and in the HNL group,most of the fat cell area increased significantly.Conclusion High-fat and high-glucose diet combined with NP exposure on pregnant rats can increase the offspring body mass,fat quality and blood lipid levels,which lead to increasing the liver fat and adipocytes,and the mechanism may be that NP leads to the expression abnormalities of adipocyte differentiation genes CEBP-α,SREBP-1,and PPARγ.