Effect Of Xiao-qing-long-tang On The Acute Lung Injury And Pulmonary Fibrosis In Animal Models

Objective To investigate whether thromboxane A₂ (TXA₂) participate in the acute lung injury and evaluate the efficacy of Xiao-qing-long-tang, a multiple ingredients herb, on the acute lung injury induced with oleic acid in guinea-pigs and pulmonary fibrosis induced with bleomycin in rats. Methods (1) An intravenous injection of oleic acid into guinea pig can produce a acute lung injury with hypoxaemia. Pretreatment of 3g/kg was administrated orally twice a day for 2 weeks, and at day 15, blood gas measurement, determination of TXB₂ level (a stable metabolite of TXA₂) and prostaglandin F_1α level (6-keto PGF_1α, a stable metabolite of PGI₂) in the plasma or bronchoalveolar lavage fluid (BALF) were performed. The arterial blood gas parameters were analyzed with a blood gas analyzer, and the level of TXB₂ and 6-keto PGF_1α were analyzed by a radioimmunoassay instrument. (2) An intratracheal instillation of a single dose of into rats can produce pulmonary fibrosis in 4 weeks. Treatment of 3 g/kg was administrated orally twice a day for 4 weeks and all rats were weighed during the experiment periods. At day 28 after BLM instillation, the animals were sacrificed, then the lungs weighted and lung/weight ratio calculated. The left lung used to staining with HE, Sirius Red and immunohistochemistry for collagen III, and the right lung used to determine the concentration of hydroxyproline. Results (1) Oleic acid injection caused a significant decrease in PaO₂, it also increased the level of TXB₂ in the plasma and BALF. Pre-treatment of Xiao-qing-long-tang attenuated the decrease in PaO₂. It also prevented increase in TXB2 and its weight ratio to 6-keto PGF_1α in BALF. (2) Xiao-qing-long-tang attenuated the increase in lung/weight ratio and the concentration of hydroxyproline in the lung tissue. It also reduced the formation of the fibrosis in HE, Sirius Red and immunohistochemistry staining. Conclusions We suggest that TXA₂ is a major...