Effects of ischemic postconditioning on pneumocyte apoptosis after lung ischemia/reperfusion injury in rats / 中国应用生理学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the effects of ischemic postconditioning (IPostC) on pneumocyte apoptosis after lung ischemia/reperfusion injury in rats.</p><p><b>METHODS</b>Adult male SD rats were randomly divided into 3 groups based upon the intervention (n = 8) control group (C), lung ischemic reperfusion group (LIR), LIR+ IPostC group (IPostC). At the end of the experiment, blood specimens drawn from the arteria carotis were tested for the content of malondialdehyde (MDA), the activity of superoxide dismutase (SOD) and myeloperoxidase (MPO); the pneumocyte apoptosis index (AI) was achieved by tennrminal deoxynucleotidyl transferase mediated dUTP nick end abeling (TUNEL); the expression of Bcl-2, Bax protein in lung tissue was accessed by quantitative immunohistochemistry (MHC) and Bcl-2, Bax mRNA by RT-PCR.</p><p><b>RESULTS</b>IPostC could significantly attenuate the MDA level, MPO activity and improve SOD activity in blood serum which was comparable to I/R and significantly reduced the number of TUNEL-positive cells compared with I/R group, expressed as Al (% total nuclei) from (39.0 +/- 3.46) to (8.0 +/- 0.88) (P < 0.01). The protein and mRNA expression of Bcl-2 and Bax showed that IPO significantly attenuated the ischemia/reperfusion-upregulated expression of Bax protein but improved the expression of Bcl-2 that improved the Bcl-2/Bax ratio (P < 0.01) .</p><p><b>CONCLUSION</b>IPostC may attenuate pneumocyte apoptosis in LIRI by up-regulating expression of Bcl-2/Bax ratio and by inhibiting oxidant generation and neutrophils filtration.</p>