Transforming growth factor -alpha improves memory impairment and neurogenesis following ischemia reperfusion

ABSTRACT

Stroke is most important cause of death and disability in adults. The hippocampal CA1 and sub-ventricular zone neurons are vulnerable to ischemia that can impair memory and learning functions. Although neurogenesis normally occurs in the dentate gyrus [DG] of the hippocampus and sub-ventricular zone [SVZ] following brain damage, this response is unable to compensate for severely damaged areas. This study aims to assess both neurogenesis and the neuroprotective effects of transforming growth factor-alpha [TGF-alpha] on the hippocampus and SVZ following ischemia-reperfusion. In this experimental study, a total of 48 male Wistar rats were divided into the following groups surgical [n=12], phosphate buffered saline [PBS] treated vehicle shams [n=12], ischemia [n=12] and treatment [n=12] groups. Ischemia was induced by common carotid occlusion for 30 minutes followed by reperfusion, and TGF-alpha was then injected into the right lateral ventricle. Spatial memory was assessed using Morris water maze [MWM]. Nestin and Bcl-2 family protein expressions were studied by immunohistochemistry [IHC] and Western blot methods, respectively. Finally, data were analyzed using Statistical Package for the Social Sciences [SPSS, SPSS Inc., Chicago, USA] version 16 and one-way analysis of variance [ANOVA]. TGF-alpha injection significantly increased nestin expression in both the hippocampal DG and SVZ areas. TGF-alpha treatment caused a significant decrease in Bax expression and an increase in Bcl-2 anti-apoptotic protein expression in the hippocampus. Our results showed a significant increase in the number of pyramidal neurons. Memory also improved significantly following TGF-alpha treatment. Our findings proved that TGF-alpha reduced ischemic injury and played a neuroprotective role in the pathogenesis of ischemic injury