Anti-oxidative effect of triterpene acids of Eriobotrya japonica (Thunb.) Lindl. leaf in chronic bronchitis rats

The study was to evaluate the effect of triterpene acids of Eriobotrya japonica (Thunb.) Lindl. leaf (TAL) on expression of antioxidative mediators by alveolar macrophages (AM) in rats with chronic bronchitis (CB), CB was induced by endotracheal instillation of lipopolysaccharedes (LPS) followed by Bacillus Calmette–Guérin (BCG) injection through caudal vein 1 week later. Treatment groups received TAL at there different doses (50, 150, or 450 mg/kg daily, intragastrically (i.g.)) or dexamethasone (1.2 mg/kg daily i.g.) for 2 weeks, 7 days after LPS injection. AM were then isolated and incubated. Superoxide dismutase (SOD) and methylene dianiline (MDA) levels in AM were measured by commercial kits; meanwhile, heme oxygenase-1 (HO-1) expression and its mRNA expression in AM were detected by immunocytochemistry and RT–PCR, respectively. HO-1 activity of the lung was also detected by a specific biochemistry reaction. The levels of MDA and HO-1 expressed by cultured AM and the HO-1 activity in the lung of the TAL groups were significantly lower than those from the CB group without treatment (p < 0.01 and p < 0.05, respectively), while the SOD levels were increased in a dose-dependent manner by TAL treatment. These results suggest that TAL inhibits HO-1 expression and MDA production and up-regulates SOD expression in AM from CB rats, which might be one of molecular mechanisms of its anti-inflammatory effects in CB rats.