The Research Of Significance And Mechanism Of Treatment With Active Vitamin D₃ For Rats With Pulmonary Fibrosis

Objective To investigate the expression and function of MMP1,MMP3,TIMP1 and miR-29a during the genesis and development of pulmonary fibrosis in rats,to probe the effects of active vitamin D3[1,25(OH)2D3]on the production and development of pulmonary fibrosis in rats,and the effect on the expression of these genes.Methods 150 male SD rats were randomly divided into prevention group and treatment group.The prevention group randomly divided into model group ?,medicine group ? and control group?,while the treatment group randomly divided into model group ?,medicine group ? and control group ?.Bleomycin was injected into the trachea of rats in the model group and medicine group,while the control group was injected with sterile saline.The prevention group and treatment group were intraperitoneally injected on the 2nd and 14th day after surgery respectively,the medicine group were injected with active vitamin D3,the model group were injected with solvent of active vitamin D3,while the control group were injected with sterile saline.In prevention group,rats were euthanized at 14th,21st and 28th day in each group in turn,and in treatment group,rats were euthanized at 21st and 28th day in each group respectively.After obtaining lung tissues from experimental rats,the difference of tissue structure and collagen fiber were compared by the HE staining and Masson staining,the difference of hydroxyproline content were compared by basic-hydrolysis method,the expression of ?-SMA,Col ?,TIMP1 mRNA and miR-29a were detected by real-time PCR,the protein expression of ?-SMA,Col ?,MMP1,MMP3 and TIMP1 were measured by immunohistochemistry,and quantized with image analysis.Results Fibrosis appeared in lungs of experimental rats treated with bleomycin after 14 days,more and more aggravated with time.The hydroxyproline content and the expression of a-SMA,Col?,MMP1,MMP3 and TIMP1 in model group ?/? and medicine group ?/? were significantly higher than that of control group ?/?(p<0.05),but the expressions of miR-29a in model group?/? and medicine group ?/?were significantly lower than that of control group ?/?at the same time points(p<0.05).In prevention group,the hydroxyproline content,the mRNA and protein expression of ?-SMA and Col ? in medicine group ? were all obviously reduced at three time points compared with model group ?(p<0.05),however,in treatment group,the hydroxyproline content,the mRNA and protein expression of a-SMA and Col ? were slightly decreased in medicine group ? compared with model group ?,but no significant difference was found(p>0.05).The expression of MMP1,MMP3 and TIMP1 in medicine group ?/? were lower than that of model group ?/? at the same time points(p<0.05),while the expressions of miR-29a in medicine group ?/? were higher than that of model group ?/? at the same time points(p<0.05).Conclusion MMP1,MMP3,TIMP1 and miR-29a play important roles in the genesis and development of pulmonary fibrosis in rats.And the active vitamin D3 may have a inhibiting effect on genesis and progression of pulmonary fibrosis in rats,with better preventive effect than therapeutic effect,and the active vitamin D3 can promote the expression of miR-29a,and inhibit the expression of MMP1,MMP3 and TIMP1,it may inhibit fibrosis by regulation of miR-29a to various target genes,including MMP1,MMP3 and TIMP1.