The Effect Of Simvastatin On The Expression Of Snail1, E-cad And Vimentin In Pulmonary Fibrosis In Rats

【Objective】The study was designed to establish the modes in bleomycin-induced pulmonaryfibrosis for observing the expression of Snail1, E-cad, vimentin and to explore theintervention effect of simvastatin on them.【Methods】Sixty healthy male SD rats were randomly divided into4groups（15rats in eachgroup）：group A (control group); group B (bleomycin group); group C (5mg SIMgroup), feeding SIM (5mg/Kg) by gavage once a day in rats since the first day aftermodeling; group D (10mg SIM group), feeding SIM (10mg/Kg) by gavage once a dayin rats since the first day after modeling. The models of pulmonary fibrosis wereestablished in Group B, C and D by single endotracheal instillation of BLM (5mg/Kg).Physiological saline of equal volume was poured into the airway in the same way ingroup A. Five rats sacrificed in each group at7th,14th and28th day. The content ofHYP in lung tissue was detected by alkaline hydrolysis test; Pathological changeswere found to observe the alveolitis and fibrosis changes of lung tissue by HE staining;The mRNA expression of Snail1, E-cad and vimentin in lung tissue was detected byRT-PCR; The protein expression of Snai1l, E-cad and vimentin was detected byImmunohistochemistry.【Results】1. HYP content:Compared with group A, the content of HYP in lung tissue of rats in group B, Cand D increased at7th,14th and28th day, the difference was statistically significant(P<0.05), group B with the highest HYP content. Compared with group B, Thecontent of HYP in group C and D decreased obviously (P<0.05), particularly group Dat28th day. 2. The pathological changes (HE staining):The lung tissue structure was normal in group A, and no inflammatory cellinfiltration, no fibrosis; and alveolar septum was not widened. The mainmanifestations in group B were the inflammatory reaction of lung tissue at7th day;The lung tissue structure was broken, and relatively more inflammatory cells andfibroblasts gathered at14th day; The lung tissue structure was destroyed seriously anda large number of proliferative fibroblasts were observed at28th day；These changesindicated that the pulmonary fibrosis had formed. The degree of pulmonary alveolitisand lung fibrosis in group C and D reduced compared with that in group B.3. Snail1, Vimentin and E-cad mRNA and protein expression:The expression of Snail1and vimentin was low, the expression E-cad was high at7th,14th and28th day in group A. However, the expression of Snail1and vimentinincreased, E-cad decreased in group B compared with group A (P<0.05). Comparedwith group B, the level of Snail1and vimentin in group C and group D by simvastatininterference reduced obviously, and the level of E-cad rised (P<0.05), particularlygroup D at28th day. The corresponding changes of mRNA and protein wereconsistent in each group during the whole experiment.【Conclusion】1. Simvastatin can inhibit or delay the process of bleomycin-induced pulmonaryfibrosis in rats.2. It’s mechanism may be associated with inhibiting the expression of Snail1andvimentin, increasing the level of E-cad, and delaying the development of the EMT.