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

OBJECTIVE: The β-gl ucans are long-chain polymers of glucose, which comprise the fungal cell wall, stimulate cells of the innate immune system, enhance disturbed epitheliza- tion, 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 preven- tion and treatment of the disease. In this experi- mental animal study, we assessed effects of β- glu can, extracted from barley, on the bleomycin- induced lung fibrosis, and evaluated differences of starting before and after bleomycin instilla- tion. MATERIALS AND METHODS: Male Spraque- Dawley rats were given a single dose of bleomycin in pulmonary fibrosis groups. First dose of β-g lucan and NAC was given three days before the bleomycin injection, and at one of the other group β-g lucan was started 12 hours after bleomycin and continued until 14 th day. Fibrotic changes in lung were estimated by using Aschoft's criteria and measuring lung hydrox- yproline content. RESULTS: Bleomycin induced severe pul- monary fibrosis with marked increase in hydrox- yproline content of lung tissue and typical lung fibrosis, which was prevented by β-g lucan. Hy- droxyproline 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-g lucan post- bleomycin group fibrosis score, hydroxyproline and MDA levels returned to the control levels. On the other hand, reduced glutathione level ele- vated in the same group. CONCLUSIONS: The data suggest that β-g lu- cans have protective and early therapeutic effects against bleomycin-induced lung fibrosis in rats.