高氧对新生大鼠肺细胞周期调节基因表达的影响

Effect of Hyperoxia on p21^(WAF/CIP1) Expression in the Lungs of Neonatal Rats

目的 探讨高氧对新生大鼠肺内细胞周期调节基因 (p2 1WAF/CIP1 )表达的影响。方法 采用Spraque -Dawley新生大鼠95 %氧暴露建立高氧肺损伤模型。应用RT PCR技术检测肺组织p2 1WAF/CIP1 mRNA水平 ,凝胶电泳条带用成像系统照相定量分析结果 ,分别计算PCR产物条带与 β actincDNA条带光密度值的比值 ,作为p2 1WAF/CIP1 基因的相对表达量。结果 新生大鼠暴露于95 %氧浓度环境中 12、2 4、48、72、96h肺组织中p2 1WAF/CIP1 mRNA表达显著增加 ,2 4h后新生大鼠肺p2 1WAF/CIP1 mRNA虽略有下降 ,但一直维持在高表达状态 ,与空气对照组相比差异有显著意义 (同一时间点的高氧组与空气对照组比较的t、P分别如下 :t=6.498 P <0 .0 0 1;t=2 7.2 0 0 P <0 .0 0 0 1;t=10 .164 P <0 .0 0 1;t=10 .481 P <0 .0 0 1;t =6.496 P <0 .0 0 1)。结论 在高浓度供氧下通过上调p2 1WAF/CIP1 基因的表达 ,阻断G0 /G1 期的肺泡上皮细胞向S期的转换 ,抑制肺泡上皮细胞生长和增殖 ,从而导致肺生长发育受阻和肺损伤。因此促进肺泡上皮细胞的生长可能成为治疗慢性肺病患儿的一种新途径。

Objective To investigate the effect of hyperoxia on p21 WAF/CIP1 gene expression in the lungs of neonatal rats.Methods Hyperoxic lung injury models were established by exposing to 95% O 2 in the neonatal period of Sprague-Dawley rats. The levels of p21 WAF/CIP1 mRNA expression in the lungs of neonatal rats exposed to 95% hyperoxia or room air were detected By RT-PCR. Electrophoresis gels with the specific positive bands were quantified by complete gel documentation and analysis system.The ratio of p21 WAF/CIP1 expression to β actin value was calculated.Results Significant increase in the level of p21 WAF/CIP1 mRNA was found in the hyperoxic-treated group at 12,24,48,72 and 96 h. Mild decrease in the level of p21 WAF/CIP1 mRNA was found in the hyperoxic-treated group after 24 h. But the level of p21 WAF/CIP1 mRNA was very high in the hyperoxic-treated group after 24 h.Conclusions Hyperoxia can up-regulate the gene expression of p21 WAF/CIP1 and lead to cell cycle arrest,thus inhibit proliferation of alveoli cells,and may affect future lung growth and lead to barrier of lung development.Therefore,exposure to high concentrations of oxygen in the neonatal period may impair lung growth and is a major contributing factor to the development of chronic lung disease (CLD). Treatment of promoting alveoli growth holds a promising future in hyperoxic lung injury. J Appl Clin Pediatr,2005,20(2):108-110