Preventive and early therapeutic effects of β-glucan on the bleomycin-induced lung fibrosis in rats.

OBJECTIVE The β-glucans are long-chain polymers of glucose, which comprise the fungal cell wall, stimulate cells of the innate immune system, enhance disturbed epithelization, and have antioxidant effects. Oxidative stress has been implicated in the pathogenesis of bleomycin-induced lung fibrosis and various antioxidant agents have been studied for prevention and treatment of the disease. In this experimental animal study, we assessed effects of β-glucan, extracted from barley, on the bleomycin-induced lung fibrosis, and evaluated differences of starting before and after bleomycin instillation. MATERIALS AND METHODS Male Spraque-Dawley rats were given a single dose of bleomycin in pulmonary fibrosis groups. First dose of β-glucan and NAC was given three days before the bleomycin injection, and at one of the other group β-glucan was started 12 hours after bleomycin and continued until 14th day. Fibrotic changes in lung were estimated by using Aschoft's criteria and measuring lung hydroxyproline content. RESULTS Bleomycin induced severe pulmonary fibrosis with marked increase in hydroxyproline content of lung tissue and typical lung fibrosis, which was prevented by β-glucan. Hydroxyproline level was significantly higher in bleomycin treated rats than the other groups, and its level was decreased in the therapeutic groups, especially in the β-glucan post-bleomycin group fibrosis score, hydroxyproline and MDA levels returned to the control levels. On the other hand, reduced glutathione level elevated in the same group. CONCLUSIONS The data suggest that β-glucans have protective and early therapeutic effects against bleomycin-induced lung fibrosis in rats.