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 following injuries of the central nervous system. In combination with bromodeoxyuridine (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 adult 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+ cells were apparently observed in the SVZ/VZ proximal to TNF-alpha injected site, and the number of BrdU+ cells increased at 6 and 24 h post injection. Since cell apoptosis was rarely found in the SVZ/VZ after TNF-alpha injection, these observations suggest that the diffusible TNF-alpha may directly and/or indirectly modulate the proliferation of neural progenitors.