Involvement of microRNA-133 and -29 in cardiac disturbances in diabetic ovariectomized rats

OBJECTIVES Menopause and diabetes obviously increase the risk of cardiovascular disease in women. The aims of the present study were to evaluate the effects of ovariectomy in type 2 diabetes on the histology and expression of miRNA-29, miRNA-133, IGF-1 and Bcl-2 genes and Bcl-2 protein and caspase 3 activity in the hearts of female rats. MATERIALS AND METHODS Forty Female Wistar rats were divided into four groups: control, sham, ovariectomized (OVX), and ovariectomized with type 2 diabetes (OVX.D). After the 8-week experiment, the histological evaluation of the heart tissue was performed using H&E staining and PAS analysis, and cardiac expression of miRNA-29, miRNA-133, IGF-1, and Bcl-2 were evaluated using real-time PCR, and Bcl-2 protein and caspase 3 activity were evaluated using Western blot and ELISA. RESULTS Ovariectomy significantly decreased miRNA-29, miRNA-133, IGF-1, and BCL-2 expression and Bcl-2 protein and increased caspase 3 activity in the heart compared to sham animals group (P<0.05). Type 2 diabetes in ovariectomized rats markedly decreased expression of miRNA-29, miRNA-133, IGF-1, BCL-2 genes, and Bcl-2 protein, and increased caspase 3 activity and reduced collagen and fibroblast tissue and glycogen granule deposition in relation to OVX group (P<0.05). CONCLUSION Our findings suggest that type 2 diabetes and menopause synergically could enhance the cardiac fibrosis through dysregulation of miRNA-29, miRNA-133, IGF-1, and Bcl-2 genes expression and Bcl-2 protein and upregulation of caspase 3 activity.