Tumor necrosis factor-alpha modulates the proliferation of neural progenitors in the subventricular/ventricular zone of adult rat brain

Little is known about the response of neural progenitors to inflammation fo llowing injuries of the central nervous system. In combination with bromode oxyuridine (BrdU) intraperitoneally (i.p.) injected, tumor necrosis factor- alpha (TNF-alpha), a proinflammatory cytokine that increased ED1+ activated microglia/macrophage population at injured sites, was administrated into a dult rat brains. No difference in the immunostaining for proliferating cell nuclear antigen (PCNA) was observed in the subventricular/ventricular zone (SVZ/VZ) between TNF-alpha injected sites and controls. However, BrdU+ cel ls were apparently observed in the SVZ/VZ proximal to TNF-alpha injected si te, and the number of BrdU+ cells increased at 6 and 24 h post injection. S ince cell apoptosis was rarely found in the SVZ/VZ after TN F-alpha injecti on, these observations suggest that the diffusible TNF-alpha may directly a nd/or indirectly modulate the proliferation of neural progenitors. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.