[Effect of hyperoxia on p53 and PCNA expression in fetal rat lung fibroblasts].

OBJECTIVE

To study the effect of hyperoxia exposure on the expression of p53 and proliferating cell nuclear antigen (PCNA) in fetal rat lung fibroblasts (LFs).

METHODS

Primary rat embryonic LFs were cultured in vitro. LFs grew to subconfluence and then were randomly divided into air and hyperoxia exposure (95% O₂, 5% CO₂) groups. After LFs were cultured for 12 and 24 hours, the proliferation was analyzed by MTT. p53 mRNA level was detected by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). p53 and PCNA protein levels were determined by Western blot.

RESULTS

After 12 and 24 hours of culture the growth inhibition rate of LFs was 8% and 23% respectively in the hyperoxia exposure group. p53 mRNA and protein levels increased significantly (P<0.01) in the hyperoxia exposure group after 12 and 24 hours of culture compared with the air exposure group. Hyperoxia exposure decreased PCNA expression after 24 hours of culture (P<0.01).

CONCLUSIONS

Hyperoxia exposure increases p53 level and decreases PCNA expression, resulting in inhibitions of LFs proliferation and DNA repair.