Intrauterine hyperglycemia and leptin resistance of offsprings

目的 探讨宫内暴露于高糖环境下的仔鼠成年期瘦素水平的变化以及对其生长发育的影响.方法 采用成年Wistar雌鼠与Wistar雄鼠杂交,在孕鼠妊娠第5天给予20%链脲霉素50 mg/kg腹腔内注射,建立高糖环境模型,为高糖组;孕鼠腹腔内仅注射柠檬酸缓冲液作为对照组.测量两组仔鼠3～10周龄的体重增长;仔鼠11周龄时,采用酶联免疫吸附试验检测其血浆瘦素水平,分析瘦素与仔鼠生长发育的相关性;应用免疫组化方法及实时定量PCR技术分别检测仔鼠下丘脑瘦素受体蛋白及mRNA表达水平[以积分吸光度(IA)值表示].结果 (1)高糖组母鼠空腹血糖为(28.3±5.1)mmol/L,明显高于对照组的(6.3±1.4)mmol/L,两组比较,差异有统计学意义(P＜0.05).仔鼠11周龄时,高糖组仔鼠空腹血糖为(5.1±0.8)mmol/L,对照组仔鼠空腹血糖为(5.3±0.6)mmol/L,两组比较,差异无统计学意义(P＞0.05).(2)高糖组仔鼠出生后3～10周的体重增长率为649.7%,显著高于对照组的479.2%,两组比较,差异有统计学意义(P＜0.05).(3)高糖组仔鼠基础胰岛素水平为(0.76±0.37)μg/,L,对照组仔鼠为(1.06±0.14)μg/L,两组比较,差异有统计学意义(P＜0.05);高糖组仔鼠基础瘦素水平为(113±37)μg/L,对照组仔鼠为(128±40)μg/L,两组比较,差异无统计学意义(P＞0.05).(4)高糖组仔鼠瘦素水平与体重增长率无相关性(r=-0.501,P=0.311);对照组仔鼠瘦素水平与体重增长率有显著负相关关系(r=-0.553,P=0.001).(5)高糖组仔鼠11周龄时下丘脑瘦素受体蛋白表达水平为4125±414,对照组仔鼠11周龄时下丘脑瘦素受体蛋白表达水平为4244±511,两组比较,差异无统计学意义(P＞0.05).高糖组仔鼠11周龄时下丘脑瘦素受体mRNA表达水平中位数为1.25,对照组仔鼠11周龄时下丘脑瘦素受体mRNA表达水平中位数为1.80,高糖组虽低于对照组,但差异无统计学意义(P＞0.05).结论 大鼠宫内高糖环境会导致仔鼠出生后3～10周体重过快增长,而瘦素水平无下降趋势,提示可能存在一定程度的瘦素抵抗;但未影响仔鼠出生后11周时的下丘脑瘦素受体表达水平的变化,宫内暴露于高糖环境下仔鼠发生的成年期瘦索抵抗并非通过下丘脑瘦素受体水平的变化所导致.Objective To study the effect of intrauterine hyperglycemia on leptin level and offspring development in rats.Methods Female and male adult Wistar rats were mated,streptozotocin (STZ,50 mg/kg) was administered intraperitoneally on 5th day of gestation to induce diabetic model,diabetic pups (DP) were exposed to intrauterine hyperglycemia;control pups(CP) were exposed to controls,which was injected with citrate buffer,8 pups were choosed from each group.Weight gain between 3-10 weeks were recorded.Plasma leptin was detected by enzyme-linked immunosorbent assay (ELISA) when the rats were 11 weeks old,and the expression of leptin receptor in hypothalamus was measured at protein level by histomorphology and mRNA level measured by realtime PCR[expressed with integral absorbance(IA)]in 11weeks in order to discuss the relation of leptin and offspring development.Results The fasting blood glucose level was significantly higher in diabetic mother compared with the controls[(28.3±5.1) mmol/Lvs.(6.3±1.4) mmol/L,P＜0.05].However,there was no difference between the fasting blood glucose level in DP group and CP group[(5.1±0.8) mmol/L vs.(5.3± 0.6) mmol/L,P ＞ 0.05].The growth rate between 3-10 weeks was significantly higher in DP group 649.7% than CP group 479.2%,P ＜0.05.The base insulin level was lower in DP group[(0.76±0.37) μg/L vs.(1.06±0.14)μg/L,P ＜ 0.05];while there was no difference in plasma leptin and the expression of ieptin receptor in hypothalamns[(113±37) μg/L vs.(128±40) μg/L,P ＞0.05].The growth rate was not associated with plasma leptin in DP group (r=-0.501,P=0.311) but associated in CP group (r=-0.553,P=0.001).The protein level of DP group (4125±414) did not significantly differ from that of CP group (4244±511).The median of mRNA of leptin receptor in hypothalamus in DP group did not altered significantly compared with that of CP group(1.25 vs 1.80,P＞0.05).Conclusions Intrauterine hyperglycemia accelerated growth rate of offsprings between 3 and 10 weeks,however,plasma leptin was not discreased,which indicated leptin resistance.Intrauterine hyperglycemia did not influence the expression of leptin receptor in hypopthalamus in offsprings,this suggested the leptin resistance may be not caused by the quantity of leptin receptors.PubMed中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)011841-8454