Aim: To observe protective effects of safflower injection (SI) on lung ischemia/reperfusion injury (LIRI) and investigate its potential mechanism.
Methods: Rabbit lung model of ischemia/reperfusion injury was constituted in vivo. The rabbits were randomly divided into three groups: sham-operation group (S group), ischemia/reperfusion group (I/R group) and ischemia/reperfusion plus safflower injection group (SI group). Malondialdehyde (MDA) content, superoxide dismutase (SOD) and xanthine oxidase (XO) activities in serum were measured. The lung tissue sampled at the end of the experiment was assayed for wet/dry weight ratio (W/D), injured alveoli rate (IAR) and ultrastructural changes were observed under electron microscope. The expression of COX-1 and COX-2 were measured by immunohistochemistry (IHC). The expressions of COX-1mRNA and COX-2mRNA were observed by in situ hybridization (ISH).
Results: In I/R group, XO and MDA increased and SOD decreased in serum, while the same changes happened in SI group but less severely(P<0.01). The value of W/D and IAR was much higher in I/R group than S group, but decreased in SI group. Electron microscope showed obvious ultrastructural injury brought by LIRI in I/R group, which was greatly attenuated in SI group. The IHC and ISH demonstrated that COX-2 and COX-2mRNA in pulmonary tissue of I/R group were significantly higher than those of SI group (P < 0.01). The difference of COX-1 and COX-1mRNA in pulmonary tissue among the three groups was not significant.
Conclusion: The ischemia/reperfusion lung injury insults induced the regulation of COX-2 in lung. Safflower injection may attenuate lung ischemia/reperfusion injury through inhibiting cyclooxygenase-2 expression.