Antioxidant and anti-apoptotic properties of Kalpaamruthaa in type 2 diabetes mellitus induced cardiovascular complications

Effect of gamma-carboxylase inhibition on serum osteocalcin may be partially protective against developing diabetic cardiomyopathy in type 2 diabetic rats

AIMS

To investigate the possible protective effect of elevated undercarboxylated osteocalcin on diabetic cardiomyopathy mechanisms and risk factors.

METHODS

In all, 32 male rats were divided into four groups: control, diabetic, diabetic warfarin and normal warfarin-treated groups. Isolated heart functions were assessed; fasting serum insulin, glucose and glycosylated haemoglobin, homeostasis model assessment insulin resistance and lipid profile were investigated. Serum undercarboxylated osteocalcin and adiponectin were also measured. In cardiac tissue, malondialdehyde content, acyl-CoA dehydrogenase gene expression, Bax/Bcl2 ratio, sarcoendoplasmic reticulum calcium ATPase and osteocalcin receptor (G protein-coupled receptor family C group 6 member A) genes expression were investigated.

RESULTS

Prophylactic elevation of undercarboxylated osteocalcin was accompanied by improved insulin sensitivity and lipid profile, increased serum adiponectin, upregulated myocardial osteocalcin receptor with preserved left ventricular function, decreased cardiac malondialdehyde content, acyl-CoA dehydrogenase and Bax/Bcl2 ratio.

CONCLUSION

Undercarboxylated osteocalcin was suggested to have protective effects against diabetic cardiomyopathy, possibly through direct action on upregulated G protein-coupled receptor family C group 6 member A and indirectly via adiponectin. These effects may be mediated through antagonizing oxidative stress and apoptosis.

Kalpaamruthaa modulates oxidative stress in cardiovascular complication associated with type 2 diabetes mellitus through PKC-β/Akt signaling

This study aimed at investigating the efficacy of Kalpaamruthaa (KA) on cardiovascular damage (CVD) associated with type 2 diabetes mellitus in experimental rats by reducing oxidative stress and the modulation of the protein kinase C-β (PKC-β)/Akt signaling pathway. CVD-induced rats were treated with KA (200 mg·(kg body mass)(-1)·(day)(-1)) orally for 4 weeks. KA effectively reduced insulin resistance with alterations in blood glucose, hemoglobin, and glycosylated hemoglobin in CVD-induced rats. Elevated levels of lipids in CVD-induced rats were decreased upon KA administration. In CVD-induced rats the levels of lipoproteins were returned to normal by KA treatment. KA effectively reduced the lipid peroxidative product and protein carbonyl content in liver of CVD-induced rats. KA increased the activities and (or) levels of enzymatic and nonenzymatic antioxidants in liver of CVD-induced rats. KA treatment reduced the fatty inclusion and mast cell infiltration in liver of CVD-induced rats. Further, treatment with KA reduced the chromatin condensation and marginization in myocardium of CVD-induced rats. KA alters insulin signaling by decreasing PKC-β and increasing p-Akt and GLUT4 expressions in heart of CVD-induced rats. The above findings suggest that KA renders protection against CVD induced by type 2 diabetes mellitus by augmenting the cellular antioxidant defense capacity and modulating PKC-β and the p-Akt signaling pathway.

Kalpaamruthaa ameliorates myocardial and aortic damage in cardiovascular complications associated with type 2 diabetes mellitus

Myocardial and aortic damage in cardiovascular complications (CVD) associated with type 2 diabetes mellitus and the protective efficacy of Kalpaamruthaa (KA) are evaluated in this study. CVD developed in 8 weeks after type 2 diabetes mellitus was induced by the administration of a high-fat diet for 2 weeks, and then with streptozotocin (2 × 35 mg·(kg body mass)(-1), by intraperitonal injection, at 24 h intervals) in male Sprague-Dawley rats. CVD-induced rats were treated with KA at 200 mg·(kg body mass)(-1)·(day)(-1) orally for 28 days. Increased oxidative stress in CVD-induced rats lowers antioxidant defense in the aorta. Treatment with KA reduced oxidative stress by increasing antioxidant status with decreased lipid peroxides in CVD-induced rats. Histological examination of the myocardium and aorta provided support for the cytoprotective effect of KA in CVD. Ultrastructural changes in the myocardium of CVD-induced rats were improved by KA treatment. Aortic damage was observed through decreased endothelial nitric oxide synthase and increased NADPH oxidase mRNA expressions in CVD-induced rats. KA reduced the aortic damage by ameliorating these levels back to normal. KA treatment reduced the pro-inflammatory cytokines tumor necrosis factor-α and interleukin 6 in CVD-induced rats. Immunohistochemical expressions of matrix metalloproteinase-2 and -9 were observed to be elevated in the myocardium of CVD-induced rats, but these were decreased by the administration of KA. This study demonstrates the cardiovascular protective effect of KA in type 2 diabetes.