Effect of capsaicin on cardiac dysfunction in diabetic rats: an in vitro experiment

Abstract

Objective To evaluate the effect of capsaicin on cardiac dysfunction in diabetic rats using an in vitro experiment. Methods Healthy male Sprague-Dawley rats, weighing 240-260 g, in which type 1 diabetes mellitus was induced by intraperitoneal streptozotocin 50 mg/kg, were studied.Eighteen diabetic rats were selected at 8 weeks after successful establishment of the model and divided into 3 groups (n=6 each) using a random number table: diabetes mellitus group (DM group), capsaicin group (CAP group) and capsaicin plus capsazepine group (CPZ group). Another 8 rats with normal blood glucose served as control group (C group). Rat hearts were quickly removed under deep anesthesia and retrogradely perfused with an oxygen-saturated K-H solution (at 37 ℃) using a Langendorff apparatus.Cardiac function was maintained stable for 10 min.The hearts were continuously perfused with K-H solution for 30 min in C and DM groups.The hearts were perfused with K-H solution for 20 min, and capsaicin (1.4×10-9 g/L) was then infused for 10 min via the branch of aortic cannula using micro pump in CAP group.The hearts were perfused with K-H solution for 10 min, and capsaicin receptor-transient receptor potential vanilloid type 1 antagonist capsazepine (1.4×10-7 g/L) was then infused for 10 min followed by infusion of capsaicin (1.4×10-9 g/L) at 0.5 ml/min for 10 min via the branch of aortic cannula using a micro-pump in CPZ group.Left ventricular systolic pressure (LVSP), left ventricular developed pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), heart rate, the maximum rate of increase or decrease in left ventricular pressure (±dp/dtmax) were recorded at 10, 20 and 30 min of continuous infusion (T1-3). Results There was no significant difference in LVEDP and ±dp/dtmax at each time point among the four groups (P>0.05). Compared with C group, LVSP and LVDP were significantly decreased at T1-3 in DM and CPZ groups and at T1-2 in CAP group, and heart rate was significantly decreased at T1-3 in DM, CPZ and CAP groups (P 0.05). LVSP and LVDP were significantly lower at T3 in CPZ group than in CAP group (P<0.05). Conclusion Capsaicin can mitigate cardiac dysfunction in diabetic rats, and the mechanism is related to activating transient receptor potential vanilloid type 1. Key words: Capsaicin; Diabetes mellitus; Heart function tests