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Experimental Diabesity Research
Volume 4, Issue 1, Pages 13-20
http://dx.doi.org/10.1080/15438600303727

The Effects of Middle Cerebral Artery Occlusion on Central Nervous System Apoptotic Events in Normal and Diabetic Rats

Department of Physiology, Wayne State University School of Medicine, 5374 Scott Hall, 540 E. Canfield, Detroit, Michigan 48201-1928, USA

Received 4 November 2002; Accepted 17 November 2002

Copyright © 2003 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Apoptosis and neural degeneration are characteristics of cerebral ischemia and brain damage. Diabetes is associated with worsening of brain damage following ischemic events. In this study, the authors characterize the influence of focal cerebral ischemia, induced by middle cerebral artery occlusion, on 2 indexes of apoptosis,TUNEL(terminal deoxynucleotidyl transferase–mediated deoxyuridine 5-triphosphate nick end-labeling) staining and caspase- 3 immunohistochemistry. Diabetes was induced in normal rats using streptozotocin and maintained for 5 to 6 weeks. The middle cerebral artery of both normal and diabetic rats was occluded and maintained from 24 or 48 hours. Sham-operated normal and diabetic animals served as controls. Following 24 to 48 hours of occlusion, the animals were sacrificed and the brains were removed, sectioned, and processed for TUNEL staining or caspase-3 immunohistochemistry. Middle cerebral artery occlusion in normal rats was associated with an increase in the number of both TUNEL-positive and caspase-3– positive cells in selected brain regions (hypothalamic preoptic area, piriform cortex, and parietal cortex) when compared to nonoccluded controls. Diabetic rats without occlusion showed significant increases in both TUNEL-positive and caspase-3–positive cells compared to normal controls. Middle cerebral artery occlusion in diabetic rats resulted in increases in TUNEL-positive as well as caspase-3–positive cells in selected regions, above those seen in nonoccluded diabetic rats. Both TUNEL staining and caspase-3 immunohistochemistry revealed that the number of apoptotic cells in diabetic animals tended to be greatest in the preoptic area and parietal cortex. The authors conclude that focal cerebral ischemia is associated with a significant increase in apoptosis in nondiabetic rats, and that diabetes alone or diabetes plus focal ischemia are associated with significant increases in apoptotic cells.