Abstract:

Objective To observe expression of microRNA (miRNA) in cardiac muscle tissues of advanced diabetic mice and to make an initial prediction of target gene regulated by difference miRNA. Methods Fifteen C57 mice were given single intraperitoneal injection of streptozotocin (STZ) to establish diabetic models (model group). Another 10 normal mice were as control group. At the end of 8 weeks after injection, left ventricular functions, including ejection fraction (EF), fractional shortening (FS), and left ventricular weight index (LVWI), were detected by using echocardiography. The mice were sacrificed for making cardiac muscle tissue samples. Then, cell morphology was observed by HE staining under optical microscope, and change of cell size was analyzed by quantitative software. Differential expressions of miRNA were performed with microarray analysis and further confirmed by quantitative real-time RT-PCR. The target gene regulated by difference miRNA was analyzed with bioinformatics. Results At the end of 8 weeks after injection, EF and FS in model group were significantly lower than those of control group, but LVWI significantly higher (P<0.05). Under histological observation, cardiac hypertrophy showed obviously in model group. There were 16 microRNAs differential expressions detected by microarray analysis in model group, including 10 up-regulated (miR-195, miR-199a-3p, miR-700, miR-142-3p, miR-24, miR-21, miRNA-221, miR-499-3p, miR-208a, and miR-705) and 6 down-regulated (miR-29a, miR-1, miR-373, miR-143, miR-20a, and miR-220b). The bioinformatics analysis indicated that the target gene regulated by miRNA involved in cell proliferation, apoptosis, glycometabolism, and angiogenesis. Conclusion MiRNA expression profile in cardiac muscle tissues of STZ induced advanced diabetic mice has significantly changes, which may contribute toward the process of diabetic cardiomyopathy.

Key words: microRNA, diabetes, cardiomyopathy, microarray