Effects of exercise training combined with insulin treatment on cardiac NOS1 signaling pathways in type 1 diabetic rats

Author： Douairon Lahaye Solène Rebillard Amélie Zguira Mohamed Malardé Ludivine Saïag Bernard Gratas-Delamarche Arlette Carré François Bekono Françoise

Publisher： Springer Publishing Company

ISSN： 0300-8177

Source： Molecular and Cellular Biochemistry, Vol.347, Iss.1-2, 2011-01, pp. : 53-62

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Abstract

This study examined the effects of a dual treatment combining insulin treatment and exercise training on basal cardiac function and signaling pathways involving β3-AR, NOS1, and RyR2 in type 1 diabetic rats. Male Wistar rats were assigned into a diabetic group receiving no treatment (D), an insulin-treated diabetic (Ins), a trained diabetic (TD), and a trained insulin-treated diabetic (TIns) group. Control group (C) was included in order to confirm the deleterious effects of diabetes. Insulin treatment and/or treadmill exercise training were conducted for 8 weeks. Basal cardiac function was evaluated by Langendorff technique. Cardiac protein expression of β3-AR, NOS1, and RyR2 was assessed using Western blots. Diabetes induced a decrease of both basal diastolic and systolic (±dP/dt) cardiac function (P < 0.05). Moreover, diabetes was associated with an increase of β3-AR and NOS1 and a decrease of RyR2 expression (P < 0.05). Although combined treatment was not able to normalize –dP/dt, it succeeded to normalize +dP/dt of diabetic rats. Combined treatment led to an overexpression of RyR2. Effects of this combined treatment on +dP/dt and RyR2 were greater than the effects of insulin and exercise training, applied solely. Treatments, applied solely or in combination, resulted in a complete normalization of β3-AR and in a down-regulation of NOS1 because this protein expression in all treated diabetic rats became lower than control values (P < 0.01). Our study shows that unlike single treatments, dual treatment combining insulin treatment and exercise training was able to normalize basal systolic function of diabetic rats by a specific regulation of β3-AR–NOS1–RyR2 signaling pathways.