[Chikusetsu saponin â £a ameliorates myocardial hypertrophy of rats through regulating expression of miR199a-5p/Atg5].

The present study investigated the effects of chikusetsu saponin Ⅳa(CHS Ⅳa) on isoproterenol(ISO)-induced myocardial hypertrophy in rats and explored the underlying molecular mechanism. ISO was applied to establish a rat model of myocardial hypertrophy, and CHS Ⅳa(5 and 15 mg·kg~(-1)·d~(-1)) was used for intervention. The tail artery blood pressure was measured. Cardiac ultrasound examination was performed. The ratio of heart weight to body weight(HW/BW) was calculated. Morphological changes in the myocardial tissue were observed by HE staining. Collagen deposition in the myocardial tissue was observed by Masson staining. The mRNA expression of myocardial hypertrophy indicators(ANP and BNP), autophagy-related genes(Atg5, P62 and beclin1), and miR199 a-5 p was detected by qRT-PCR. Atg5 protein expression was detected by Western blot. The results showed that the model group exhibited increased tail artery blood pressure and HW/BW ratio, thickened left ventricular myocardium, enlarged myocardial cells, disordered myocardial fibers with widened interstitium, and a large amount of collagen aggregating around the extracellular matrix and blood vessels. ANP and BNP were largely expressed. Moreover, P62 expression was up-regulated, while beclin1 expression was down-regulated. After intervention by CHS Ⅳa at different doses, myocardial hypertrophy was ameliorated and autophagy activity in the myocardial tissue was enhanced. Meanwhile, miR199 a-5 p expression declined and Atg5 expression increased. As predicted by bioinformatics, Atg5 was a target gene of miR199 a-5 p. CHS Ⅳa was capable of preventing myocardial hypertrophy by regulating autophagy of myocardial cells through the miR-199 a-5 p/Atg5 signaling pathway.

[Expression and bioinformatics analysis of miRNA in ISO-induced rat cardiac hypertrophy].

OBJECTIVE: To investigate the expression changes of miRNAs (miR199a-5P, miR206, miR133a-3P, miR499-5P) in rat model of cardiac hypertrophy induced by isoproterenol (ISO), and to explore the main signal pathways and molecular mechanisms which related to that with the way of bioinformatics. METHODS: Sixteen SD male rats were randomly divided into two groups: control group and ISO model group. The rats in model group were treated with ISO (1 mg/kg) to induce cardiac hypertrophy, the rats in control group were treated with the same amount of saline, and all were injected subcutaneously at the back. After 10 days of continuous administration, interventricular septal thickness at diastole (IVSd), left ventricular posterior wall thickness at diastole (LVPWd) , left ventricular end-diastolic diameter(LVDd), and systolic function (EF%) were measured by echocardiography. Heart weight (HW) and rat body weight (BW) were weighed, and heart/body weight ratio (HW/BW) was calculated. Myocardial tissues were stained with HE, and myocardial cell surface area was measured by Image J analysis software; RT-qPCR was used to detect the expressions of 4 miRNAs in rat myocardial tissues. Targetscan, miRDB and miRwalk databases were used to predict the possible target genes of four kinds of miRNAs in rats, and FunRich software was used to analyze and predict the signal pathways related to the target genes. RESULTS: Compared with the control group, the IVSd and LVPWd in the model group were thickened, the LV was increased, and the EF% was decreased significantly. The HW and HW/BW were increased. The myocardial cell volume in the model group was increased significantly, the arrangement was disordered, and the cell surface area was increased; the expressions of miR199a-5P and miR206 in the model group were up-regulated by RT-qPCR (P＜0.05); the expressions of miR133a-3P and miR499-5P were down-regulated (P＜0.05). Predicted by bioinformatics application, related signal pathways which target genes of 4 miRNAs maybe involved in cardiac hypertrophy mainly are: VEGF/VEGFR signal pathway, ErbB receptor signal pathway and other signal pathways. CONCLUSION: ISO-induced cardiac hypertrophy leads to changes in miRNA expression, and bioinformatics predicts related target genes of four miRNAs involved in cardiac hypertrophy and their major signaling pathways. These studies will provide new ideas for the regulation of cardiac hypertrophy and its prevention and treatment measures.