Effect of intermittent hypoxia on bladder detrusor cell apoptosis and regulatory mechanism of Alpiniae oxyphyllae Fructus

AIM To investigate the effect of intermittent hypoxia （IH） on bladder detrusor cells apoptosis and calcium channel， and to discuss the regulatory mechanism of Alpiniae oxyphyllae Fructus （AOF）. METHODS IH model of bladder detrusor cells was established by treating the cells with 6 cycles of 5% O₂ for 60 min and 20% O₂ for 30 min. Human bladder detrusor cells were cultured in vitro， randomly divided into 6 groups， each group had 8 holes. P₂X₃ receptor antagonist + IH （A） group， M₃ receptor antagonist + IH （B） group， β₃ receptor antagonist + IH （C） group， AOF + IH （D） group， saline + IH control （NC） group and air simulation control （AC） group were set up. The cells density and morphology were identified by the methods of counting chamber and immunofluorescence light microscopy （LM） after interventions. The apoptosis was analyzed by flow cytometry. Calcium channel expression was detected by patch clamp. RESULTS （1） Compared with the cells in AC group， the cells density and activity were significantly increased in NC group （P<0.05）； some cells appeared protrusions， turned round and blur in cell borders. （2） The results of immunofluorescence for detecting α-SMA protein expression showed that， compared with the cells in group AC， the mean absorbance （MA） in group NC was significantly increased （F=3.25， P<0.05）； compared with the cells in group NC， that in group A and group D was both decreased significantly （P<0.05）. （3） Compared with the cells in group AC， the apoptotic rate was significantly decreased in group NC （P<0.05）； Compared with the cells in group NC， the apoptotic rates in group A and group D were both significantly increased （P>0.05）. （4） Compared with the cells in group AC， calcium ion channel expression was significantly decreased （P<0.05）. Compared with the cells in group NC， calcium ion channel expression in AOF （100 mg/L） and AOF （50 mg/L） group was significantly increased （P<0.05）. CONCLUSION IH regulates bladder detrusor cells proliferation and apoptosis through P₂X₃ bladder nerve receptors， high or moderate dose of AOF may change calcium channel and play a protective role in IH induced cell damage.