Chronic Cerebral Hypoperfusion Induces Alterations of Matrix Metalloproteinase-9 and Angiopoietin-2 Levels in the Rat Hippocampus

Angiogenic factors contribute to cerebral angiogenesis following cerebral hypoperfusion, and understanding these temporal changes is essential to developing effective treatments. The present study examined temporal alterations in angiogenesis-related matrix metalloproteinase-9 (MMP-9) and angiopoietin-2 (ANG-2) expression in the hippocampus following bilateral common carotid artery occlusion (BCCAo). Male Wistar rats (12 weeks of age) were randomly assigned to sham-operated control or experimental groups, and expression levels of MMP-9 and ANG-2 were assessed after BCCAo (1 week, 4 weeks, and 8 weeks), using western blotting. Protein expression increased 1 week after BCCAo and returned to control levels at 4 and 8 weeks. In addition, immunofluorescence staining demonstrated that the MMP-9- and ANG-2-positive signals were primarily observed in the NeuN-positive neurons with very little labeling in non-neuronal cells and no labeling in endothelial cells. In addition, these cellular locations of MMP-9- and ANG-2-positive signals were not altered over time following BCCAo. Other angiogenic factors such as vascular endothelial growth factor and hypoxia-inducible factor did not differ from controls at 1 week; however, expression of both factors increased at 4 and 8 weeks in the BCCAo group compared to the control group. Our findings increase understanding of alterations in angiogenic factors during the progression of cerebral angiogenesis and are relevant to developing effective temporally based therapeutic strategies for chronic cerebral hypoperfusion-associated neurological disorders such as vascular dementia.

Attenuation of Neuronal Damage by Gymnemic acid in Experimentally Induced Cerebral Ischemia in Rats.

Gymnemic acid is obtained from the natural resource and has got antioxidant property, was investigated for the possible neuroprotective effect in experimentally induced cerebral ischemic rats. Carotid arteries clamped with the help of aneurysm clips to produce cerebral ischemia, the clips were removed from the arteries to allow the reflow of the blood through carotid arteries. It was observed that lipid peroxidation was increased significantly after bilateral common carotid artery occlusion. Brain endogenous antioxidant GSH and total protein levels were low. Administration of gymnemic acid in a dose of 250 mg/kg and 500 mg/kg b.w orally showed promising neuroprotective effect by reducing cerebral infarct size as well as improved all antioxidant levels showing activity against oxidative stress.