新生后给药地塞米松对大鼠肺形态发育的影响

Effects of postnatal dexamethasone on rat lung morphogenesis

目的:比较生后给予不同剂量地塞米松(dexamethasone,DEX)对大鼠肺组织形态发育的影响。方法:120只新生大鼠随机平均分为3组。小剂量DEX组:生后第5天起连续5天腹腔注射DEX0.2mg/(kg·d)。大剂量DEX组:生后第5天起连续5天腹腔注射DEX0.5mg/(kg·d)。生理盐水组:生后第5天起连续5天腹腔注射等量生理盐水。各组大鼠分别在生后第10、14、21、45天随机选取10只处死,分离肺组织,通过光镜观察,分析比较各组用药对肺形态发育的影响。结果:两DEX治疗组在生后各时间点每视野肺泡计数均低于生理盐水组(P﹤0.01),平均肺泡表面积均高于生理盐水组(P﹤0.05)。两DEX治疗组平均肺泡间隔厚度在生后第10、14天均低于生理盐水组(P﹤0.01),在生后第21天均高于生理盐水组(P﹤0.05)。结论:生后给DEX能显著促进肺部早期发育,但随着给药剂量的增多,肺泡化受阻现象逐渐明显,最终导致肺泡大而少的"气肿样"改变出现,其影响可持续至成年。

Objective：To compare the effects of different dosage of dexamethasone （DEX） on rat lung morphogenesis. Methods： Total of 120 newborn rats were divided into three groups randomly：a small dosage DEX group,a large dosage DEX group and a control group. On the 10th,14th,21st,45th days after birth,the histologic structures of 10 rat lungs in each group were observed with light microscope. Results：Under the light microscope,during the first 2 weeks,rat lungs in the two treatment groups had fewer alveolar numbers,larger alveolar space,and thinner alveolar septum compared with those in the control group （P〈0.01）. On the 21st and 45th days,the airspaces of rat lungs in the two treatment groups were still enlarged,while the alveolar spetums were thickening. An ＂emphysematous＂condition of the lungs could be observed especially in the large dosage DEX group. Conclusion：Using DEX postnatal could promote lung morphogenesis obviously,while with the dose increased,the normal alveolization was inhibited,and the impact continued well into adulthood.