Effects of safflor injection on expression of cyclooxygenase-2 mRNA during lung ischemia/reperfusion injury in rabbits

AIM: To investigate the effects of safflor injection (SI) on expression of cyclooxygenase-2 mRNA during lung ischemia/reperfusion injury (PIRI) in rabbits. METHODS: Rabbit lung model of ischemia/reperfusion injury was constructed in vivo. The rabbits were randomly divided into three groups: sham-operation group (group S), ischemia-reperfusion group (group I/R) and ischemia/reperfusion plus safflor injection group (group SI). The lung tissue sampled at the end of the experiment was assayed for wet/dry weight ratio (W/D), injured alveoli rate (IAR) and observed ultrastructure changes under electron microscope. The expressions of COX-1 and COX-2 were measured by immunohistochemistry (IHC). The expression of COX-1 mRNA and COX-2 mRNA were observed by in situ hybridization (ISH). RESULTS: The value of W/D and IAR was much higher in I/R group, but decreased in SI group. Electron microscope showed obvious ultrastructure injury brought by PIRI in I/R group, which was greatly attenuated in SI group. The IHC and ISH demonstrated that COX-2 and COX-2 expressions in pulmonary tissue of I/R group were significantly higher than those in S group (P<0.01). The difference of COX-1 and COX-1 expressions in pulmonary tissue was not observed among three groups. CONCLUSION: The lung ischemia-reperfusion insult induces the up-regulation of COX-2 in lung. Safflor injection may attenuate lung ischemia-reperfusion injury through inhibiting COX-2 expression.