宫内慢性缺氧致子代大鼠成年后胰岛素抵抗和高血压

Prenatal chronic hypoxia in rats leads to insulin resistance and hypertension in adult offspring

目的研究宫内慢性缺氧大鼠成年后是否出现胰岛素抵抗及高血压,以及胰岛素抵抗与高血压两者的相关性。方法SD(Sprague Dawley)孕鼠25只,随机分为5组,4组缺氧处理(缺氧组),1组正常对照(对照组)。其中缺氧组在妊娠不同时期缺氧处理[氧浓度(10±1)%,每天定时缺氧3 h],分为孕全期(1~21 d)、早期(1~7 d)、中期(8~14 d)、晚期(15~21 d)缺氧(H1,H2,H3,H4)组,对照组模拟放入缺氧箱中,氧浓度21%。出生子代大鼠分别于1 d龄、3月龄、6月龄每组随机各取雌雄子鼠5只。选用无创血压仪检测子鼠血压,血糖仪检测子鼠空腹血糖,放射免疫法检测空腹血清胰岛素(FINS),采用稳态模式评估检测稳态模型胰岛素抵抗指数(HOMA-IR),测定肾脏质量指数,免疫组织化学法检测肾脏胰岛素受体(InR)蛋白表达,荧光定量聚合酶链反应(PCR)检测肾脏胰岛素受体底物(IRS-1、IRS-2)mRNA含量,Western-blot法检测肾脏InR、IRS-1、IRS-2蛋白表达。结果各缺氧组子鼠血压于3月龄明显升高,6月龄升高更加显著,与对照组差异有统计学意义(P<0.05);6月龄孕全期、早期缺氧组空腹血糖[雌鼠(5.78±0.21)、(5.69±0.29)比(4.73±0.14)mmol/L,雄鼠(5.84±0.19)、(5.76±0.24)比(4.79±0.23)mmol/L]、HOMA-IR[雌鼠(3.35±0.34)、(3.23±0.26)比(2.71±0.23),雄鼠(3.55±0.25)、(3.18±0.33)比(2.66±0.39)]升高,与对照组差异有统计学意义(均P<0.05);空腹血糖、HOMA-IR与血压指标呈正相关(P<0.05);各缺氧组子鼠肾脏质量指数于3月龄开始低于对照组,6月龄差异更加显著(P<0.05);肾脏InR、IRS-1和IRS-2 mRNA和蛋白表达于6月龄表现出差异,孕全期、早期缺氧组较对照组表达明显减少(均P<0.05)。结论宫内慢性缺氧可能通过宫内不良生长环境引起子代大鼠成年后胰岛素抵抗及高血压,胰岛素抵抗与高血压两者间存在相关性。

Objective To investigate the effects of chronic intrauterine hypoxia on insulin resistance,hypertension,and the correlation between them in adult offspring rats.Methods A total of 25 pregnant Sprague Dawley(SD)rats were randomly divided into 5 groups:4 prenatal chronic hypoxia groups(H groups)and a control group(C group).Control group was put into anoxic chamber with 21%oxygen concentration.H groups were divided into whole(1-21 day),early(1-7 day),middle(8-14 day)and late(15-21 day)prenatal hypoxia groups(H1,H2,H3,H4 group)with rats being put into hypoxia box(10%±1%O2)3 hours per day.Five male and 5 female offspring in each group were studied when the descendant rats were 1 day-,3 month-and 6-month-old.Fasting blood glucose(FBG)was measured by blood glucose meter,fasting serum insulin(FINS)was detected by radioimmunoassay,and insulin resistance index was calculated by homeostasis model insulin resistance index(HOMA-IR).Renal mass index was also measured.The expression of insulin receptor(InR)protein,the expression of insulin receptor substrate(IRS)-1 and IRS-2 mRNA and the expression of InR,IRS-1 and IRS-2 protein in kidney were detected by immunohistochemistry,fluorescent quantitative polymerase chain reaction(PCR)and Western blot,respectively.Results The blood pressure index of offspring rats in H groups were lower than that in C group at 3 months old,and the difference was more significant at 6 months old(P<0.05).The level of FBG[female(5.78±0.21),(5.69±0.29)vs(4.73±0.14)mmol/L,male(5.84±0.19),(5.76±0.24)vs(4.79±0.23)mmol/L],HOMA-IR[female(3.35±0.34),(3.23±0.26)vs(2.71±0.23),male(3.55±0.25),(3.18±0.33)vs(2.66±0.39)]in the whole pregnancy hypoxia and the early pregnancy hypoxia group were statistically higher than those in C group(P<0.05)at 6 months old.FBG and HOMA-IR were positively correlated with blood pressure(P<0.05).The renal mass index in each hypoxia group was lower than that in C group at 3 months old,and the difference was more significant at 6 months old(P<0.05).The expressions of InR,IRS-1 and IRS-2 mRNA and protein in the kidneys in hypoxia groups were significantly decreased at 6 month old in whole pregnancy and early hypoxia groups when compared with the C group(P<0.05).Conclusions Chronic intrauterine hypoxia may cause insulin resistance and hypertension in adult offspring rats through poor intrauterine growth environment and there is a correlation between insulin resistance and hypertension.