Type 2 diabetes mellitus (T2DM) is a major risk factor for ischemic stroke accompanied by vascular dysfunction and poor cerebrovascular outcome. Lixisenatide is a glucagon like peptide-1 (GLP-1) analog that is recently used for T2DM treatment with established neuroprotective properties. This study investigated and compared the neuroprotective effect of lixisenatide against glimepiride on diabetic rats subjected to global cerebral ischemia/reperfusion (I/R) injury. T2DM-induced adult male Wistar rats were administered lixisenatide or glimepiride prior to induction of global cerebral I/R-induced injury. Results showed a disturbance in oxidative stress parameters (catalase, reduced glutathione, and malondialdehyde) along with increasing in caspase-3 and tumor necrosis factor-alpha protein expressions in ischemic diabetic brain tissues. An upregulation of protein level of inducible nitric oxide (iNOS) synthase and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit, NOX2 gene expression associated with significant suppression of endothelial nitric oxide synthase (eNOS) protein expression are recorded in carotid arteries of diabetic I/R-injured rats. Apart from ameliorating glucose intolerance and insulin resistance, lixisenatide was found to be superior to glimepiride as protective treatment in terms of enhancing behavioral/neurological functions and suppressing cerebral oxidative stress, inflammation, and apoptosis in cerebral I/R-injured diabetic rats. Unlike glimepiride, lixisenatide relieved carotid endothelial dysfunction by increasing eNOS expression. It also dampened vascular nitrosative/oxidative stress via suppression of iNOS and NADPH oxidase expressions. This study supposed that lixisenatide represents a more suitable anti-diabetic therapy for patients who are at risk of ischemic stroke, and even so, the mechanisms of lixisenatide-mediated vascular protection warrant further experimental and clinical investigations.
Keywords: Cerebral ischemia/reperfusion; GLP-1; Glimepiride; Lixisenatide; Type 2 diabetes mellitus; Vascular injury.