OBJECTIVETo investigate the effects of lidocaine on apoptosis and proliferation of hyperoxia-exposed type Ⅱalveolar epithelial cells (AECⅡ) from premature rats.

METHODSPrimary cultured AEC Ⅱ isolated from premature rats were randomly divided into four groups: air, air+ lidocaine (20 μg/mL), 95%O2/5%CO2, and 95%O2/5%CO2+ lidocaine. The cells in each group were collected 24 hrs after culture in ordinary incubators (37℃,5%CO2). The proliferation and apoptosis of AEC Ⅱ were detected by flow cytometry. Protein levels of proliferating cell nuclear antigen (PCNA) were measured by Western blot.

RESULTSThe apoptosis rate of AECⅡincreased, the percentages of G2/M and S phase cells decreased and the protein levels of PCNA decreased significantly in the group exposed to 95%O2/5%CO2 compared with the group exposed to air (P<0.01). Lidocaine treatment decreased apoptosis rate of AECⅡ, increased percentage of G2/M and S phase cells, and increased protein levels of PCNA.

CONCLUSIONSHyperoxia can increase apoptosis and inhibit proliferation of AECⅡ in premature rats. Lidocaine may have protective effects against the AECⅡ injuries.