Oridonin protects the lung against hyperoxia-induced injury in a mouse model.

Hyperoxic acute lung injury (HALI) is caused by prolonged exposure to high oxygen partial pressure. This study was undertaken to investigate the protective effects of oridonin on HALI in a mouse model. Mice were randomly divided into three groups: the control group, HALI group and oridonin (ORI) group. HALI was induced by exposing mice to pure oxygen at 2.5 atmospheres absolute (ATA) for six hours in the HALI and ORI groups. In the ORI group, mice were intraperitoneally injected with ORI at 10 mg/kg twice daily after hyperoxic exposure. Animals were sacrificed 24 hours after the hyperoxia exposure, followed by bronchoalveolar lavage fluid (BALF). Lungs were then collected. Each lung was processed for HE staining and detection of wet-to-dry weight ratio. The lactate dehydrogenase (LDH) activity and protein content of BALF were determined, and the contents of malonaldehyde (MDA), glutathione (GSH), tumor necrosis factor alpha (TNF-?) and interleukin-10 (IL-10) in the lung were measured. Our results showed prolonged exposure to hyperoxia significantly damaged the lung, caused lung edema, increased MDA and TNF-?, and reduced GSH and IL-10 in the lung. However, post-exposure treatment with oridonin was able to improve lung pathology, attenuate lung edema, reduce MDA and TNF-?, and increase GSH and IL-10 in the lung. These findings suggest that oridonin can protect the lung against hyperoxia-induced injury in mice.