Cerebroprotective effect of calcium channel blocker in diabetes associated with stroke

Abstract

Background and Objective: Calcium channel blocker act as neuroprotective and antidiabetic agent by targeting voltage gated Calcium channels and arresting beta cell death respectively. Therefore, the study were performed using efonidipine to demonstrate its cerebroprotective effect in diabetes associated cerebrovascular complications. Material and Method: Four days old neonates were injected with streptozotocin (STZ, 90 mg/kg, i.p.). Diabetes was confirmed after 12 weeks and animals were randomly divided into 8 groups: normal control, sham operated, MCAO operated, normal treated with efonidipine (1mg/kg/day, p.o.). Diabetic control, diabetic sham operated, diabetic MCAO, diabetic MCAO treated with efonidipine (1mg/kg/day, p.o.). The treatment with efonidipine (1mg/kg/day, p.o.) started after 16 weeks of diabetes induction was continued for 4 weeks. After 4 weeks, all the animals were anaesthetized and middle cerebral artery occlusion was carried out. After 24 hours of surgery, neurological score was determined. Blood was collected for determination of biochemical parameters like serum glucose, lipid profile, CK-MB, LDH, IL-6 and TNF-α levels. Brain was excised for neuropathological changes such as brain infarct area, hemisphere weight difference, Na+-K+ ATPase activity, cell viability assay, oxidative stress parameters. Ang-2 and TGF-β, VEGF gene were investigated for determination of molecular mechanism. Results: MCAO induced animals treated with efonidipine showed significant reduction in brain infarct volume, difference in brain hemisphere weight, neurological score, Na+-K+ ATPase activity, serum CK-MB and LDH levels as compared to the MCAO induced animals. No significant changes were observed in the serum glucose levels and lipid profile in MCAO induced animals after treatment with efonidipine. Diabetic MCAO induced animals treated with efonidipine showed significant reduction in brain infarct volume, difference in brain hemisphere weight difference, neurological score, Na+-K+ ATPase activity, serum CK-MB, LDH, glucose, lipid level as compared to the diabetic MCAO induced group. No significant changes were observed in the serum glucose levels and serum HDL levels was observed after treatment with efonidipine. Efonidipine treated diabetic MCAO induced animals showed significant increase in antioxidant enzymes like reduced glutathione, catalase and superoxide dismutase level and significant decrease in malionaldehyde, acetyl cholesterase and nitrite level were observed. In gene expression study, down regulation of TGF-β, and VEGF was observed after treatment. Conclusion - Treatment with efonidipine has neuroprotective effect in diabetic ischemic insulted brain. Down regulation of TGF-β and VEGF, antioxidant property of calcium channel blocker may be implicated in brain protection.