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Cardiac fibrosis is a common pathologic change along with pressure overload. Recent studies indicated that transient receptor potential (TRP) channels played multiple roles in heart. However, the functional role of transient receptor potential vanilloid-3 (TRPV3) in cardiac fibrosis remained unclear. The present study was designed to investigate the relationship between TRPV3 activation and pressure overload-induced cardiac fibrosis. Pressure overload rats were successfully established by abdominal aortic constriction (AAC), and cardiac fibrosis was simulated by 100 nM angiotensin II (Ang II) in neonatal cardiac fibroblasts. Echocardiographic parameters, cardiac fibroblast proliferation, cell cycle, intracellular calcium concentration ([Ca2+] i ), and the protein expressions of collagen I, collagen III, transforming growth factor beta 1 (TGF-β1), cyclin E, and cyclin-dependent kinase 2 (CDK2) were measured. Echocardiographic and histological measurements suggested that the activation of TRPV3 exacerbated the cardiac dysfunction and increased interstitial fibrosis in pressure overload rats. Further results showed that TRPV3 activation upregulated the expressions of collagen I, collagen III, TGF-β1, cyclin E, and CDK2 in vivo and in vitro. At the same time, blocking TGF-β1 pathway could partially reverse the effect of TRPV3 activation. These results suggested that TRPV3 activation exacerbated cardiac fibrosis by promoting cardiac fibroblast proliferation through TGF-β1/CDK2/cyclin E pathway in the pressure-overloaded rat hearts.

The aim of this study was to evaluate the antiarrhythmic effect of allicin (AL) on streptozotocin (STZ)-induced diabetic rats and explore the possible mechanisms. Hyperglycemia was induced in rats by single intraperitoneal injection of STZ (40 mg/kg). Three days after STZ treatment, the hyperglycemic rats (plasma glucose levels≥16.7 mM) were administered with AL (4, 8, and 16 mg/kg) by intraperitoneal injection daily for 28 days. The fasting blood glucose levels were measured on every seventh day during the 28 days of treatment. The body weight and blood glucose levels were detected after 28 days. Antiarrhythmic effect of AL was observed in the diabetic rats induced by BaCl2. To determine the ionic mechanism in rat ventricular myocytes of AL, action potential duration (APD), L-type calcium current (ICa-L), and inward rectifier potassium current (IK1) were recorded by the whole cell-patch clamp technique. The expressions of L-type calcium channel protein α1C mRNA and cell potassium channels protein Kir2.1 mRNA were studied by RT-PCR. AL normalized the RR interval and QT interval in diabetic rats. AL obviously delayed the onset of ventricular arrhythmia and reduced the score of arrhythmia induced by BaCl2. Electrophysiological experiment revealed that AL could shorten APD through inhibition of ICa-L and enhancement of IK1. RT-PCR analysis indicated that long-term treatment with AL could decrease the expression of α1C mRNA and increase the expression of Kir2.1 mRNA. AL has antiarrhythmic effect in STZ-induced diabetic rats. It is tempting for the application of AL to be a useful therapeutic approach in diabetes with ventricular arrhythmia.