Enforced physical training promotes neurogenesis in the subgranular zone after focal cerebral ischemia

• Published in: Journal of the neurological sciences 2008-06, Vol.269 (1), p.54-61
• Main Authors: Lee, Seung-Hoon, Kim, Yun-Hee, Kim, Young-Ju, Yoon, Byung-Woo
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Bromodeoxyuridine - metabolism; Cell Count - methods; Cell Proliferation; Cerebral Ventricles - pathology; Dentate Gyrus - pathology; Disease Models, Animal; Focal cerebral ischemia; Infarction, Middle Cerebral Artery - pathology; Infarction, Middle Cerebral Artery - rehabilitation; Male; Medical sciences; Nerve Tissue Proteins - metabolism; Neurogenesis; Neurologic Examination; Neurology; Neurons - physiology; Physical Conditioning, Animal - methods; Physical training; Rats; Rats, Sprague-Dawley; Recovery; Subgranular zone; Subventricular zone; Time Factors; Vascular diseases and vascular malformations of the nervous system
• ISSN: 0022-510X; 1878-5883
• DOI: 10.1016/j.jns.2007.12.028

Abstract Background Cerebral ischemia increases neurogenesis in the subventricular zone (SVZ) and in the subgranular zone (SGZ) of the dentate gyrus, and this might be modulated by an enriched environment including voluntary physical activity. We examined whether enforced physical training (EPT) influences neurogenesis in the SVZ and SGZ after cerebral ischemia. Methods Adult male Sprague–Dawley rats were subjected to focal cerebral ischemia for 2 h, and divided into an EPT and a non-EPT group. All rats in the EPT group were trained using a rota-rod for 14 days. 5-bromo-2'-deoxyuridine (BrdU) was injected to determine levels of cell proliferation. Functional recovery was assessed using a set of behavioral test batteries. Extents of endogenous neurogenesis in the SVZ and SGZ were quantified by immunofluorescence staining. Although final infarction volumes were not significantly different in the groups, functional recovery was better in the EPT group at 10 and 17 days after ischemia. In the SVZ, BrdU labeling and double labeling of BrdU/Dcx and of BrdU/NeuN were not significantly different in the two groups. However, in the SGZ, EPT significantly increased the number of BrdU-positive cell numbers (EPT vs. non-EPT: 159.1 ± 19.9 vs. 101.8 ± 7.8, p = 0.04), and the number of BrdU/Dcx double-labeled cells (130.6 ± 16.9 vs. 73.6 ± 7.2, p = 0.01). Conclusions The results obtained indicate that EPT promotes neurogenesis in the SGZ of the dentate gyrus after ischemia, but not in the SVZ. The biochemical mechanism that determines the differential effects of EPT remains to be clarified.