Treatment with ammonia induces apoptosis and necrosis of rat astrocytesin vitro

AIM:To investigate whether treatment with ammonia induces apoptosis and necrosis of rat astrocytes in vitro and to analyze the pathogenesis of hepatic encephalopathy. METHODS:Primary astrocytes isolated from the cerebral cortex of newborn rats were cultured in vitro and identified by immunocytochemistry (positive for glial fibrillary acidic protein). Cells were then randomly assigned to low-concentration ammonia group (treated with 2.5 mmol/L NH4Cl),high-concentration ammonia group (treated with 5 mmol/L NH4Cl),and control group (untreated). After culture for 24,48,and 72 h,cell apoptosis and necrosis were detected by flow cytometry. RESULTS:Treatment with ammonia at a concentration of 2.5 mmol/L could induce astrocyte apoptosis and necrosis,and apoptosis-and necrosis-inducing activity of ammonia was concentration-and time-dependent. Compared with the control group,the apoptosis and necrosis rates of astrocytes in the high-concentration ammonia group were significantly higher (24 h:12.5% ±4.0% vs 7.7% ±1.9%,9.3% ±1.6% vs 6.3% ±0.7%; 48 h:17.7% ±4.2% vs 8.5% ±1.3%,10.5% ±2.8% vs 7.2% ±1.1%; 72 h:23.9% ±4.1% vs 9.6% ±1.9%,11.4% ±2.5% vs 7.9% ±1.5%,all P < 0.05). CONCLUSION:Treatment with ammonia could induce astrocyte apoptosis and necrosis in vitro in a time-and concentration-dependent manner.