高脂饮食对幼鼠生长及胰岛素样生长因子表达的影响

摘要

目的 研究高脂饮食对幼鼠生长及胰岛素样生长因子(IGF-I)表达的影响,闸明血清和肝脏组织IGF-I代谢紊乱与非酒精性脂肪性肝病(NAFLD)幼鼠生长迟缓的关系.方法 21日龄SD雄性大鼠40只,随机分成正常(N)组、高脂(HF)组.高脂饮食成功诱导NAFLD幼鼠造模成功后,测定血清IGF-I及胰岛素样生长因子结合蛋白-3(IGFBP-3)水平,采用RT-PCR与Western-blot检测肝脏IGF-I和IGFBP3的mRNA和蛋白表达.结果 5周高脂饲料喂养后,高脂组幼鼠肝脏符合典型的NAFLD病理特征;与正常组相比,高脂组血清总胆固醇(TC)、血清高敏C反应蛋白、血清ALT及肝组织三酰甘油(TG)含量均显著升高(P均＜0.01).高脂组幼鼠体质量、鼻-尾长度较正常组增长缓慢(P＜0.01).胫骨长度和股骨长度两组差异无统计学意义;高脂组股骨的骨密度和骨矿含量均低于正常组(P均＜0.05).高脂组幼鼠血清IGF-I和IGFBP-3均较正常组表达显著下降(P均＜0.01);血清生长激素(GH)两组差异无统计学意义(P＞0.05);高脂组肝脏组织IGF-I和IGFBP3 mRNA和蛋白表达水平与血清学结果一致.结论 血清IGF-I浓度与大鼠鼻-尾长度、体质量呈正相关,长期高脂饮食幼鼠生长迟缓,可能与肝脏组织和血清IGF-I浓度减低有关.%Objective To investigate the effects of high-fat feeding on growth and expression of insulin-like growth factor- I CIGF- I) level in young rats, and to illustrate the relationship between growth failure in young rats with non-alcoholic fatly liver disease (NAFLD) and IGF-I turbulence. Methods Forty SD young rats of 3 weeks old were randomly divided into two groups, normal group (N) and high-fat feeding group (Hfi. The levels of serum IGF-I and insulin-like growth factor binding protein 3 (1GFB13) were determined in NAPU) rats induced by high fat feeding. The mRNA and protein level of 1GK-1 and 1CPRP3 in liver tissue were measured by RT-PCR and Western-blot methods. Results The typical pathological change of NAFLD was observed in young rats induced by high-fat feeding for 5 weeks. The levels of total cholesterol (TC) , C-reactive protein (CRP) and alanine ami no Iran sferase ( ALT) were significantly higher in HF group than in N group <,P < 0.01). The level of liver triglyceride (TG) was significantly higher in HF group than m N group (P < 0.01 ). The body weight and the nose-tail length were significantly decreased. The femoral and the tibial lengths were shorter in HF group than in N group, but this reduction was not significant. The femoral bone mineral density (BMD) and bone mineral content (BMC) were lower m HF group than in N group (P < 0.05). The levels of serum IGF-I and IGFBP3 were significantly lower in HF group than in N group. The liver tissue mRNA and protein level of IGF I and ICFBP3 were significantly decreased in HF group than in N group (P < 0.01). The serum growth hormone ( CH) level was lower m HF group than in N group, but this reduction was not significant. Conclusions Serum IGF I is correlated with the nose tail length and the weight. The growth restriction of young rats,induced by high-fat feeding, may be related to the decreased expression of ICF-I.