Methods: The study included 70 female Wistar albino rats (weighing 180 to 200 g). We created seven groups, each consisting of 10 rats. Then, we generated acute lung injuries by intra-tracheal peroxynitrite injection in every group except for the control group. We investigated the effect of oleanolic acid. For this purpose, we measured the levels of malondialdehyde, interleukin 1 beta, interleukin 4, interleukin 10 and tumor necrosis factor alpha in the collected blood samples from the rats. In addition, we examined the lung tissue samples histopathologically and assessed the rate of apoptosis.

Results: Peroxynitrite injected groups at 24 and 48 h showed a statistically significant increase in interleukin 1 beta, tumor necrosis factor alpha, interleukin 4, interleukin 10 and malondialdehyde levels, which are accepted as mediators of the inflammatory process, compared to the control group. When peroxynitrite injected groups at 24 and 48 h were compared to the treatment groups of the same hour, a statistically significant decrease was detected. According to histopathological examination, peroxynitrite injected groups at 24 and 48 h showed a significant increase of tissue injury scores compared to the control group. However, the groups that were treated with oleanolic acid showed a significant decrease compared to the peroxynitrite groups (p<0.001 for tumor necrosis factor alpha and apoptosis results at 48 h).

Conclusion: In this study, we confirmed that oleanolic acid can be an effective agent for the prevention of acute lung injury generated via peroxynitrite.