高氧暴露下早产大鼠血清皮质醇变化的动态研究

目的研究高氧暴露下,早产大鼠皮质醇(GC)动态变化,探讨其与支气管肺发育不良(BPD)发生之间的关系。方法妊娠21d剖宫产娩出的早产大鼠随机分为实验组和对照组,实验组大鼠持续吸入>90%O2,对照组大鼠呼吸空气。于生后1d,3d,7d,14d,和21d取肺组织行HE染色。于生后3d,7d和14d,从两组中随机选取仔鼠断头取血,应用放射免疫法测定血清皮质醇浓度。结果对照组早产大鼠血清皮质醇浓度在检测的各时间点无显著性改变,实验组大鼠的血清皮质醇浓度在生后3d时与对照组比较无显著性差异(n=25,P=0.56),在生后7d时显著高于对照组(n=25,P=0.04),在生后14d时显著低于对照组(n=21,P=0.0018)。高氧组早产鼠肺脏表现出BPD样病理改变,各时间点高氧组辐射状肺泡计数明显低于对照组(P<0.05),生后3d,7d,14d和21d时,高氧组肺纤维化评分明显高于对照组(P<0.05)。结论高氧暴露可以导致早产大鼠肺纤维化,影响肺发育。早产大鼠的血清皮质醇浓度在高氧暴露时有明显改变,可能参与肺损伤的发生过程,影响糖皮质激素的疗效。

Effect of prolonged hyperoxia exposure on serum cortisol in preterm rats

Objective To investigate the effect of prolonged hyperoxia exposure on serum cortisol in preterm rats. Methods Preterm rats were assigned randomly into hyperoxia group ( >90%O2)and control group(room air). On postnatal 3rd(P3) ,7th(P7), and 14th (P14)day, the serum cortisol concentrations were detected by radio immuno analysis in both groups. On P1, P3, P7, P14, and P21, the lung pathology were studied. Results On P3, the serum cortisol concentrations were similar between two groups (n = 25, P = 0.56) . Compared with control group, the serum cortisol concentration in hyperoxia group was higher on P7 (n = 25, P = 0.04), and was lower on P14(n = 21, P = 0.0018) .The pathological changes were similar to those in bronchopulmonary dysplasia (BPD)infants. At all time points,the rad- ical alveolar counts in hyperoxia group were lower significantly than those in control group (P < 0.05).On P3, P7, P14, and P21, the lung fibrosis scores in hyrproxia group were higher than those in control group( P < 0.05). Conclusions Exposure to hyperoxia may result in lung fibrosis in preterm rat and retard growth of lung. Serum cortisol in hyperoxia preterm rat changes significantly, this may contribute to lung injury and reduce the clinic efficiency of glu-cocorticorid. Abnormal glucocorticoid secretion may play an important role in BPD.