地塞米松对早产胎鼠生长发育的影响及与IGF-I的相关性

The relationship between the premature delivery rats after different dose of antenatal(dexamethasone) therapy and IGF-Ⅰ

目的:探讨产前应用地塞米松在促进早产胎鼠肺成熟的同时对早产胎鼠生长发育的影响以及早产胎鼠生长发育与IGF-Ⅰ的相关性。方法:随机将W istar孕大鼠18只分为3组,地塞米松单剂量组(SD-DXM)、多剂量组(MD-DXM),对照组(CT)。单剂量组在孕鼠14天9时颈部皮下注射0.1mg地塞米松,多剂量组在孕鼠14、15天9时和21时颈部皮下注射0.1mg地塞米松,对照组在孕鼠14天9时颈部皮下注射等量的生理盐水。孕鼠怀孕至16.5天行剖宫产终止妊娠,比较用药组与对照组胎鼠肺脏成熟和生长发育情况。用放射免疫法测定孕鼠血清、胎鼠羊水中IGF-Ⅰ含量,进行同组间的相关性分析。结果:(1)应用地塞米松后胎鼠出生体重、呼吸评分和心脏重量/体重提高;肺脏重量/体重、肝脏重量/体重、全脑重量/体重降低;(2)孕鼠血清IGF-Ⅰ的变化:SD-DXM组高于CT组,差异有统计学意义(P<0.05)。MD-DXM组低于CT组,差异有统计学意义(P<0.01);(3)羊水IGF-Ⅰ的变化:SD-DXM组与CT组比较无统计学意义(P>0.05)。MD-DXM组低于CT组,差异有统计学意义(P<0.01);(4)孕鼠血清中IGF-Ⅰ含量远高于胎鼠羊水中IGF-Ⅰ含量,两者无相关性。结论:(1)地塞米松可以促进早产胎鼠肺脏成熟,地塞米松的不同剂量对胎鼠肺脏、肝脏、心脏、脑等重要脏器的发育有影响,单剂量应用地塞米松对胎鼠生长发育的不良影响小于多剂量组。(2)孕鼠血清中IGF-Ⅰ水平不能作为评价胎鼠生长发育的指标。

Objective：To investigate the growth effect in the premature delivery rats after different dose of antenatal dexamethasone therapy and the relationship of growth of fetal rats and, ,insulin-like growth factor-Ⅰ （IGF-Ⅰ ）.Methods： Eighteen Wistar pregnant rats were randomly divided into three groups and received different dose of antenatal dexamethasone at the dose of 0. 1 mg neck subcutaneous injection. Single dose of dexamethasone group（SD-DXM） （n = 6） received dexamethasone on the 14th day of gestation only at 9am. Muhidose of dexametha- sone group （MD-DXM） （ n = 6 ） received dexamethasone on the 14th, 15th day of gestation at 9am and 9pm. The control group （CT） （ n = 6） received equivalent volumes of isotonic saline on the 14th day of gestation only at 9am. The pregnancy was ended on the 16.5th day using ce- sarean delivery. The maturity lung and growth of control group and dexamethasone therapy groups were compared. The radioimmunoassay was used to measure serum and amniotic IGF-Ⅰ. Results： （ 1 ） The birth weight, the breath score and heart weight/birth weight of SD-DXM group and MD-DXM group were higher than that of the control（P 〈 0.01 ）. Lung weight/birth weight,liver weight/birth weight and brain weight/birth weight of fetal in each pregnant rat were lower than that of the control（P 〈0.01 ） ; （2） Serum IGF-Ⅰ of pregnant rats in the SD-DXM group was higher than that of the control （ P 〈 0.05 ）. Serum IGF-Ⅰ of pregnant rats in the MD-DXM group was lower than that of the control group（ P 〈 0. 01 ） ;（3 ）There were no sig- nificant difference of IGF-Ⅰ fetal rats amniotic fluid between the SD-DXM group and the con- trol group （ P 〉 0.05 ）. Fetal rats amniotic fluid IGF-Ⅰ in the MD-DXM group was also lower than that of the control,P 〈 0.01;（4）Serum IGF-Ⅰ of pregnant rats was higher than amniotic fluid IGF-Ⅰ , there were not correlation. Conclusion： Prenatal dexamethasone treat may accelerate the lung mature and decrease fetal rats organ weight/birth weight such as heart,brain ,lung and liver. Serum IGF-Ⅰ of pregnant rats can not assess fetal rats growth as standard.