Astrocytic Response in the Striatum and Corpus Callosum of the Brain of Adult Wistar Rats with Global Ischaemia

Abstract

Ischaemic stroke occurs when the blood supply to a part of the brain is suddenly interrupted. Astrocytes are known to maintain ionic homeostasis, scavenge free radicals and support neurogenesis. This study examined the astrocytic responses in the corpus callosum and striatum to global ischaemia with functional deficits in adult male rats. The common carotid artery (CCA) in adult rats was occluded temporarily (30 min) or permanently and then kept for 24 h or three days, while a sham operation was done for the control (n=10 per group). Neurobehavioural testing for motor deficits (square grid and pole tests) were carried out before sacrifice. The rats’ brains were stained with haematoxylin and eosin, and immunohistochemically with anti-glial fibrillary acidic protein for astrocytes. Quantitative data from behavioural tests were compared using analysis of variance, and significance was set at 0.05. The rats with permanent CCA occlusion had increased latency to turn and return to the base in the pole test, and reduced latency to fall in the square grid test compared to the temporary occlusion and control groups. Sections of the corpus callosum and striatum had increased proliferation and hypertrophy of the astrocytes in the permanent CCA occlusion, which was less obvious in the temporary occlusion group compared to the control. Global ischaemia caused neuronal degeneration and reactive astrogliosis in the corpus callosum and striatum, which were more pronounced in the group with permanent arterial occlusion than those that underwent reperfusion. Early reperfusion is crucial for structural and functional recovery following brain ischaemia in stroke management, and astrocytes play important roles in both the pathogenesis and recovery process.