[Effect of different tidal volume ventilation on apoptosis and the expression of Bax and Bcl-2 in rat lungs]

Abstract

Objective: To determine the effect of different tidal volume(Vt) ventilation on apoptosis and the expression of Bax and Bcl-2 in rat lungs.

Methods: Twenty-four healthy SD rats were randomly divided into 4 groups: a control group, a low Vt ventilation group (LV), a middle Vt ventilation group (MV), and a high Vt ventilation group (HV). Rats were subjected to different tidal volumes (10,20,and 40 mL/kg) for 2 h except the control group, which kept their own breath. We determined the lung histopathology score, W/D ratio and WBC in bronchoalceolar lavage fluid (BALF) to evaluate the lung injury and examine the apoptotic cell death, Bax and Bcl-2 protein expression by using TUNEL technique and immunohistochemistry 24 h after the operation.

Results: Compared with the control group, MV and HV increased lung histopathology score, W/D ratio, WBC in BALF, apoptosis index (AI )and Bax protein expression, but decreased Bcl-2 protein expression (P<0.05). These changes showed no significant difference between the control group and the low Vt ventilation group (P>0.05).

Conclusion: Low Vt ventilation contributed little to apoptosis. Higher Vt ventilation can improve Bax while inhibit Bcl-2 expression to aggravate apoptosis in rat lungs.