AIMTo explore the effect of baicalein (Bai-Chinese Traditional Medicine) on bleomycin (BLM)-induced fibrosis in lungs of rats and its possible mechanism.

METHODSSixty-eight male Sprague-Dawley rats were randomly divided into 4 groups: BLM plus Bai group, BLM plus normal saline (NS) group, NS plus Bai group, and NS plus NS group. The rats were received single intratracheal instillation of BLM (5 mg kg(-1) bw) or equal volume of NS as control, and received intraperitoneal injection o f Bai (12.5 mg x kg(-1) bw) or the same volume of NS asvehicle for 28 d. The hydroxyproline content, the collagen area, the mRNA expression of Col I (alpha), and the myofibroblasts in lung were examined.

RESULTSThe content of hydroxyproline, the percentage of collagen area, the mRNA expression of Col I (alpha), and the amount of myofibroblast were increased in lungs of rats on day 28 after intratracheal instillation of BLM, compared with that in lungs of the control rats, respectively( All P < 0.01). The above abnormal changes were ameliorated by Bai (12.5 mg x kg(-1) x d(-1) ip, x 28 d (All P < 0.05).

CONCLUSIONBai has anti-action on BLM-induced fibrosis in lung, and that the above action of Bai is related to the blockage of synthesis of type I collagen and the decrease of myofibroblast in lung.