Results At 24 h, 48 h and 72 h, sevoflurane cell survival rates were significantly lower than that of the control group (Control group:(88.31±8.20)%, (80.42±9.04)%, (75.63±7.84)%; Sevo group:(71.53±6.95)%, (61.35±7.38)%, (45.40±5.42)%. t = 3.491, 3.654, 7.092, P < 0.001. In the low dose BNP group, survival rates were: (72.41±8.42)%, (67.22±6.46)%, (50.11±5.71)%. t = 2.567, 2.030, 4.556, P = 0.028, 0.034, 0.000.In the moderate dose BNP group, survival rates were: (76.68±5.95)%, (72.53±5.10)%, (54.58±6.73)%. t = 2.567, 2.030, 4.556, P?= 0.028, 0.034, 0.000. High dose BNP group: (79.32±6.44)%, (75.68±5.47)%, (60.09±4.28)%, t = 2.183, 2.048, 3.890, P = 0.023, 0.036, 0.000). Cell survival rate of each treatment group was significantly higher than that of the sevoflurane group (Sevo group: (71.53±6.95)%, (61.35±7.38)%, (45.40±5.42)%. Low dose BNP group: (72.41±8.42)%, (67.22±6.46)%, (50.11±5.71) %. t = 1.180, 2.038, 2.317, P = 0.216, 0.030, 0.019. Moderate dose BNP group: (76.68±5.95)%, (72.53±5.10) %, (54.58±6.73) %. t = 2.180, 2.787, 2.376, P = 0.028, 0.017, 0.020. High dose BNP group: (79.32±6.44)%, (75.68±5.47)%, (60.09±4.28)%, t = 2.206, 3.488, 4.756, P = 0.022, 0.000, 0.000), and with the increasing of BNP concentration, cell survival rate was significantly increased (Low dose BNP group: (72.41±8.42)%, (67.22±6.46)%, (50.11±5.71)%. Moderate dose BNP group: (76.68±5.95)%, (72.53±5.10)%, (54.58±6.73)%. High dose BNP group: (79.32±6.44)%,(75.68±5.47)%, (60.09±4.28)%, F = 2.182, 2.491, 2.384, P = 0.020, 0.024, 0.022). Flow cytometry showed apoptosis of nerve cells treated with sevoflurane was significantly higher than the control group (Sevo group and the apoptosis was prevented by addition of BNP in a dose-dependent manner:(67.49±7.92)%, Low dose BNP group:(60.72±8.33)%, moderate dose BNP group: (44.95±7.21)%, High dose BNP group:(31.86±6.50)%, Control group:(19.42±4.58)%, F = 6.583, P < 0.001). The expression of Bcl-2 was lower in the sevoflurane group than the control group; BNP increased the expression of Bcl-2; sevoflurane treatment increased Bax and Caspase-3 protein expression, which was prevent by BNP.