Effect of NO/NOS on apoptosis of rat alveolar epithelial cells induced by acute high-concentration oxygen inhalation

AIM: To study the effect of nitric oxide/nitric oxide synthase(NO/NOS) on apoptosis of rat alveolar epithelial cells induced by acute high-concentration oxygen inhalation.METHODS: Healthy Wistar rats were randomly divided into 5 groups(half male and half female,n=12 each): air control group,4 h group,8 h group,12 h group and 16 h group.The rats were exposed to 85%~100% oxygen in a self-made chamber for different time periods and the rats in control group were kept in normal room air(21% oxygen).The levels of malondialdehyde(MDA),NO and NOS in plasma and lung tissues were detected.The protein expression of eNOS and iNOS in the lung were measured by Western blotting.The apoptosis of alveolar epithelial cells was determined using TUNEL technique.RESULTS: Compared with control group,the levels of MDA,NO and NOS in plasma and lung tissues markedly increased in all hyperoxia groups(P0.01).The protein expression of eNOS was clear in control group,increased at 4 h,and obviously increased at 8 h,12 h and 16 h after hyperoxia exposure.The protein expression of iNOS was far lower than that of eNOS in control group,and slightly increased at 16th h.The number of apoptosis cells increased by 9.13%±3.20%,17.47%±3.50%,19.22%±4.50% and 11.03%±2.80% at 4 h,8 h,12 h and 16 h after exposed to high-concentration oxygen,respectively,compared with control group.The indexes in plasma and lung tissues and the number of cell apoptosis had significant positive correlations.CONCLUSION: NO/NOS may play a very important role in the apoptosis of rat alveolar epithelial cells exposed to hyperoxia.