Effects of Rosiglitazone on Transforming Growth Factor-β_1 and its Signaling Pathway Genes Expressions in Pulmonary Tissue of Otsuka Long-Evans Tokushima Fatty Rats

Objective To explore effects and its mechanism of Rosiglitazone treatment on transforming growth factor-β_1/Smad(TGF-β_1/Smad)signaling pathways in Otsuka Long-Evans Tokushima Fatty(OLETF)rats.Methods Sixteen OLETF rats were divided into two groups:DM group and rosiglitazone-treated group(RGT group),and 8 of Long Evans Tokushima Otsuka(LETO)rats as control(N group).RGT group rats were treated with rosiglitazone(3 mg/kg/day,in drinking water) for 12 weeks,starting at the age of 30 weeks.The structural and collagen deposition changes of pulmonary tissue in three groups rats were observed by HE and Masson staining;the expression of Smad7 and collagen type III in lung tissues were examined by western blotting;the expression of TGF-β_1 of lung tissues were examined by ELISA.Results The expression of TGF-β_1,Smad3 and collagen type Ⅲ increased in pulmonary tissues of OLETF rats,which higher than those of LETO rats(P0.05).The expression of Smad7 decreased in OLETF group(P0.05).Pulmonary interstitial and perivascular of LETO rats had some collagen fibers,which increased and disordered in OLETF rats.Rosiglitazone partially reversed all of these parameters(P 0.05).Conclusions Rosiglitazone may improve diabetic pulmonary fibrosis probably via TGF-β_1/Smad signaling pathways.