Effect of L-arginine on expression of bcl-2 and bax mRNA in pulmonary injury induced by ischemia-reperfusion in rabbits

AIM:To investigate the effect of L-arginine (L-Arg) on expression of bcl-2, bax mRNA during pulmonary ischemia and reperfusion injury (PIRI) in rabbits.METHODS:Single lung ischemia and reperfusion animal model was used in vivo. The rabbits were randomly divided into three groups: sham operated group (sham, n=12), ischemia-reperfusion group (I/R, n=12) and I/R+ L-arginine group (L-Arg, n=12). Changes of several parameters, which included apoptotic index (AI), wet to dry ratio of lung tissue weight (W/D) and index of quantitative assessment of histologic lung injury (IQA), were measured at 300 min after reperfusion in lung tissue. Meanwhile the location and expression of bcl-2, bax mRNA as well as the ratio of bcl-2 mRNA/bax mRNA were observed. The lung tissue was prepared for light microscopic and electron microscopic observation at 60, 180 and 300 min after reperfusion. RESULTS:As compared with I/R group, in intima and extima of small pulmonary artery, alveoli, and bronchiole epithelia, the expression of bcl-2 mRNA and the ratio of bcl-2 mRNA/bax mRNA were increased, and the expression of bax mRNA was decreased in L-Arg treatment group. The values of AI, W/D and IQA showed significantly lower than that in I/R group at 180 minutes after reperfusion in lung tissue (P<0.01 and P<0.05). Meanwhile, abnormal changes of the lung tissue in morphologically were markedly lessened in L-Arg treatment group.CONCLUSION:L-arginine produces a notable protective effect on PIRI in rabbits by up-regulating bcl-2 mRNA expression, down-regulating bax mRNA expression in lung tissue and regulating the balance of bcl-2 mRNA and bax mRNA to decrease apoptosis.