ABSTRACT
Objective To investigate the effect of hyperoxia on growth of type Ⅱ alveolar epithelial cells (AECⅡ).MethodsLungs of fetal rats at 19 days of pregnancy were collected,and AEC Ⅱ was isolated and cultured by differential adherence method.Cells were randomly divided into air group and hyperoxia group.In air group,cells were cultured in 5％ CO2 incubator.And cells in hyperoxia group were cultured in 5％ CO2+95％ O2 incubator.The growth,activity,cell cycle,cell apoptosis of AEC Ⅱ were observed at 2,4,6 and 8 days of culture.The interaction between different time and groups were analyzed by ANOVA of factorial design.Comparison of means was done by two-sample independent t test and one-way analysis of variance.Bonferroni correction was used during the comparisons.Results(1) Cell growth situation:in hyperoxia group,cell number was decreased from2 hto 8 h [(7.29±0.43)×105/ml,(2.68±0.37)×105/ml,(0.23±0.10)×105/ml and (0.00±0.00) × 105/ml],and lower than those in air group [(10.41 ± 0.24) × 105/ml,(27.90±1.91) × 105/ml,(27.12±0.85) ×105/ml and (26.29±1.59) × 105/ml](t=10.992,38.912,94.166and 49.696,P=0.000 respectively). (2) Cell activity:the living cells ratio in hyperoxia group at 2 d[(79.00±0.71) ％],4 d [(52.80±1.14)％] and 6 d [(31.60±1.52)％] was lower than those [(97.00±0.71)％,(97.20±0.84)％ and (95.00±0.71)％] ir air group (t=31.213,70.519 and 84.722,P=0.000 respectively).(3) Cell cycle:the cell ratios of G1 phase and S phase in hyperoxia group at day 4 [(66.82±1.20) ％ and (27.31±1.16) ％] and day 6 [(70.22±1.27) ％ and (30.31±1.40) ％] were significantly higher than that at day 2 and that in air group (P＜0.05 respectively).(4) Cell apoptosis:in hyperoxia group,the cell ratio of Annexin-V+/PI- subgroup at 4 h was the highest [(23.89 ± 0.52)％],followed by those at day 2 and 6 [(21.32 ± 0.43)％ and (1.47 ±0.61)％].While the cell ratio of Annexin-V+/PI+ was the highest at 6 h [(53.92± 1.64)％],followed by those at 4 h and 2 h [(45.03±1.01)％ and (12.17±0.60)％],which were all different with those in air group(P＜0.05 respectively).ConclusionsHyperoxia might inhibit cell activity and cell cycle of AEC Ⅱ and promote apoptosis.