产前给药地塞米松对大鼠胎肺形态发育的影响

Effects of antenatal dexamethasone on rat fetal lung morphogenesis

目的:比较产前给予不同剂量、不同疗程的地塞米松(DEX)对大鼠胎肺形态发育的影响。方法:15只孕鼠随机分为5组,每组3只。小剂量DEX单程组:孕16、17天注射等量生理盐水,孕18天腹腔注射DEX0.4mg/(kg·d)。小剂量DEX多程组:孕16、17、18天腹腔注射DEX0.4mg/(kg·d)。大剂量DEX单程组:孕16、17天注射等量生理盐水,孕18天腹腔注射DEX0.8mg/(kg·d)。大剂量DEX多程组:孕16、17、18天腹腔注射DEX0.8mg/(kg·d)。生理盐水组:孕16、17、18天注射等量生理盐水。孕19天每只孕鼠取6只胎鼠肺组织作为早产鼠肺模型,通过光镜观察及电镜技术,分析比较各组用药对胎肺形态发育的影响。结果:光镜下,小剂量DEX单程、多程组及大剂量DEX单程、多程组每视野肺泡计数,平均肺泡间隔厚度均低于生理盐水组(P﹤0.01),平均肺泡表面积均高于生理盐水组(P﹤0.01)。透射电镜观察,地塞米松治疗组Ⅱ型肺泡上皮内多见板层小体且染色深、致密;胞质内线粒体等细胞器多见,而生理盐水组内难见板层小体、少见细胞器;基底膜呈现由完整到断裂不连续、由厚薄均一到厚薄不均甚至无法辨认的变化。结论:产前给药地塞米松能显著促进胎肺发育,但随着给药剂量和次数的增多,肺泡化受阻和基底膜受损现象逐渐明显。

Objective：To compare the effects of different dosage of dexamethasone （DEX） on rat fetal lung morphogenesis. Methods：Fifteen pregnant rats were divided into five groups with 3 rats in each group randomly：small dosage DEX single and multi- ple course groups,large dosage DEX single and multiple course groups and control group. On the 19th day of gestation,cesareans were taken out,and the histologic structures of 6 fetal rat lungs in each pregnant rat were observed with light microscope and elec- tronic microscope. Results：Under the light microscope,fetal rat lung in the four treatment groups had fewer alveolar numbers, larger alveolar space,and thinner alveolar septum compared with control group （P 〈 0.01）. With the increased dosages and times of the DEX,the fetal rat lungs have fewer alveolar numbers,larger alveolar space,and thinner alveolar septum （P 〈 0.01 ）. Under the electronic microscope, lamellar body and cellular organs such as bioblast in endochylema of the four treatment groups were more obvious compared with the control group. But basal membrane of lung epithelial cells turned out to be discontinuous and different thickness. Conclusion：Using DEX antepartum could promote fetal lung morphogenesis obviously. But with the dose and course increased, the development alveoli was inhibited and the basal membrane was damaged.