Protective effect of Xuebijing injection on paraquat-induced pulmonary injury via down-regulating the expression of p38 MAPK in rats

BACKGROUND Exposure to paraquat results in acute lung injury. A systemic inflammatory response has been widely established as a contributor to paraquat-induced acute lung injury. Recent studies have reported that consumption of Xuebijing prevents inflammatory response-induced diseases. This study investigated whether consumption of Xuebijing protected rats against paraquat-induced acute lung injury. METHODS Adult male Sprague Dawley rats were randomly divided into four groups: control group; paraquat group; paraquat + Xuebijing group; and paraquat + dexamethasone group. Rats in the paraquat, paraquat + Xuebijing and paraquat + dexamethasone groups were intraperitoneally injected with paraquat (30 mg/kg) or administered paraquat and Xuebijing at 8 mL/kg or dexamethasone at 5 mg/kg, respectively, via an injection into the tail vein. Lung p38 MAPK, NF-κB65, IkB, p-IκB-α, HIF-1α, Nrf2 and TGF-β1 expression were essayed using western blotting. IL-6, TNF-α, IL-1β, IL-10, TGF-β1 and PIIIP were measured using ELISA. ROS, oxidised glutathione and glutathione activity were measured. RESULTS After inducing acute lung injury with paraquat for 24 h, Xuebijing was observed to block lung p-p38 MAPK, NF-κB65, HIF-1α, p-IκB-α and TGF-β1 expression, and increased Nrf2 and IkB expression. The numbers of neutrophils and lymphocytes and total number of cells were significantly lower in the Xuebijing group compared with the control group. IL-6, TNF-α, IL-1β, TGF-β1 and PIIIP levels were significantly decreased in the Xuebijing group. ROS and oxidised glutathione activity were markedly inhibited by Xuebijing. Histological evaluation showed attenuation of the effects of Xuebijing on paraquat-induced lung injury. Compared with the paraquat + dexamethasone group, the Xuebijing + paraquat group showed no significant differences. CONCLUSIONS Inhibiting the expression of p38 MAPK and NF-κB65 was crucial for the protective effects of Xuebijing on paraquat-induced acute lung injury. The findings suggest that Xuebijing could effectively ameliorate paraquat-induced acute lung injury in rats. Xuebijing was as effective as dexamethasone at improving paraquat-induced lung injury by regulating lung inflammation, lung function and oxidative stress responses.