| 【Objective】To observe the expression of5-HTR2B in the bleomycin-inducedpulmonary fibrosis tissue of rats and to investigate the relativity between5-HTR2Band Epithelial-Mesenchymal Transition.【Methods】45healthy male SD rats were randomly divided into contral group,bleomycin group and bleomycin+prednisone group(15in each group). The model ofpulmonary fibrosis of rats was established single intra-trachea instillation ofbleomycin (5mg.kg-1) in bleomycin group and prednison group. Five rats in eachgroup randomly sacrificed at7th,14th and28th day after eastablishing models. Thelung tissue was observed by microscopein HE and Masson staining. Lunghydroxyproline (HYP) content was evaluated. The expression of Protein and mRNAof5-HTR2B、E-cadherin（E-cad）and alpha-smooth muscle actin (α-SMA) wereanalyzed by Immunohistochemistry and/or RT-PCR.【Results】1.HE staining:when bleomycin group compared with contral group, Inflammation isthe main performance at7th day; a small amount of lung fibroblasts appeared at14thday; A lot of myofibroblasts gathered in the lung tissues at28th day and this showedthat the pulmonary fibrosis models had been built. When bleomycin+prednisonegroup compared with bleomycin group, similar changes occurred in between themduring the testes, but bleomycin+prednisone group had relatively mild pulmonaryfibrosis.2. HYP content: the content of HYP increased in bleomycin group compared withcontral group (P <0.05), and reached the highest at28th day. The content of HYPdecreased in bleomycin+prednisone group compared with bleomycin group (P <0.05). 3.5-HTR2B, α-SMA and E-cad protein and mRNA expression:5-HTR2B,a-SMAhad lower expression and E-cad had higher expression in the lung tissue of contralgroup. The experimental results by Immunohistochemistry and RT-PCR showed thatthe protein and mRNA expression of5-HTR2B and a-SMA enhanced in pulmonaryfibrosis in rats (P <0.05), and reached the highest at28th day; the correspondingprotein and mRNA expression of E-cad reduced (P <0.05), and reduced to the lowestvalue at28th day. When bleomycin+prednisone group compared with bleomycingroup, the corresponding protein and mRNA expression of5-HTR2B and a-SMAdecreased (P <0.05), however, the corresponding protein and mRNA expression ofE-cad had increased in different degree (P <0.05).4. Correlation analysis: In the lung tissues of rats with pulmonary fibrosis, a positivelycorrelation was found between the expression of5-HTR2B and a-SMA (r=0.976, P<0.05), a negative correlation was found between the expression of5-HTR2B withE-cad (r=-0.927, P <0.05).【Conclusion】5-HTR2B is involved in the pathogenesis of bleomycin induced pulmonary fibrosisand may contribute to it thought EMT. |
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