高氧致慢性肺疾病新生大鼠肺泡损伤及肺泡上皮细胞的变化

目的 探讨高浓度氧致新生鼠肺损伤时肺泡形态学变化和肺泡上皮细胞动态变化.方法 通过吸入85%～90%高浓度氧气建立新生鼠慢性肺疾病组织模型.80只新生鼠分为实验组和对照组,实验组(n=40)吸人85%～90%氧气,对照组(n=40)吸入空气.分别留取1、3、7、14、21 d的肺组织,应用放射状肺泡计数(RAC)并且测量肺泡间隔厚度以判定肺泡发育情况,应用免疫组化及RT-PCR技术测定肺组织表面活性蛋白C(SPC)、水通道蛋白-5(AQP5)蛋白及mRNA表达.结果 在生后1 d和3 d,两组RAC和肺泡间隔厚度差异无显著性(P>0.05).在7 d和14 d,实验组的RAC明显低于对照组(P<0.01),肺泡间隔厚度高于对照组(P<0.01),21 d时肺泡间隔厚度升至最高,与对照组间比较差异有显著性(10.62±5.01 vs 3.62±0.88,P<0.001),RAC降至最低,与对照组间比较差异有显著性(3.57±1.24 vs10.47±0.88,P<0.001).高氧肺损伤实验组SPC 3 d时表达明显减少,7d后开始增多,14 d、21d明显高于对照组;而AQP5随着肺损伤的加重表达进行性下降.结论 高氧肺损伤可导致肺泡发育停滞,明显损伤肺泡上皮细胞,肺泡上皮细胞特异性标志物SPC、AQP5表达结果提示I型肺泡上皮细胞损伤严重,Ⅱ型肺泡上皮细胞虽然数量有所增加但其分化与转化能力明显下降.

Alveolar damage and the alveolar epithelial cell change in neonatal rats with chronic lung disease induced by hyperoxia

Objective To explore the changes of alveolar morphology and alveolar epithelial cells in rats with hyperoxia-induced chronic lung diseases (CLD). Methods CLD model in neonatal rats was established by inhalation of high concentration oxygen(85%～90% ). Eighty neonatal rats were randomly exposed to hyperoxia (model group) and to room air (control group) (n =40 each). Radical alveolar counts and the alveolar septum thickness were used to evaluate alveolar development. The site and intensity of expression of SPC,AQP5 protein were detected by immunohistochemical staining,the dynamic expression of SPC mRNA,AQP5mRNA was detected by RT-PCR on day 1,3,7,14 and 21 after exposure. Results There were no significant differences about alveolar wall thickness and RAC between experimental groups and control group on day 1～3 ( P > 0. 05 ). But there was significant difference between the model group and the control groups on day 7 and 14 (P <0. 01 ). For model group,alveolar septum thickness peaked on day 21, the difference was significant compared with control group ( 10. 62±5.01 vs 3.62±0. 88, P < 0. 001 ), but RAC decreased to the lowest level, the difference was significant compared with control group ( 3.57±1.24 vs 10. 47±0. 88,P <0. 001 ). The expression of SPC decreased on day 3 manifestedly but increased on day 7 and the levels of SPC were higher than that in the control group. Experimental group showed gradual decrease in AQP5 expression as the lung impairment devastated. Conclusion Alveolar development was delayed and alveolar epithelial cell (AEC) was damaged in the neonatal CLD rats. The changes of SPC,AQP5 expression suggested AECI was severely damaged and failed in full recovery, meanwhile the quantity of AEC Ⅱ was increased but the ability of its differentiation and transformation was decreased.