Microglial reaction in some CNS nuclei following nerves transection in BALB/c and interferon-gamma gene knockout mice

The present study was aimed to ascertain if the endogenous IFN-gamma is nec essary for induction of microglial reaction associated with the CNS neurons after neurectomy of the vagus and hypoglossal nerves in IFN-gamma gene kno ckout mice and BALB/c mice serving as controls. Vigorous microglial reactio n as detected by Mac-1 antibody was elicited in the brainstem nuclei in bot h strains of mice. Increased Mac-1 immunoreactivity in microglia was detect ed as early as 1 day post-operation in the ipsilateral dorsal nucleus of va gus, nucleus ambiguus and the hypoglossal nucleus; a similar feature was ob served in the nucleus tractus solitarius bilaterally. Mac-1 immunoreactivit y in reactive microglia appeared to increase with survival intervals and wa s comparable throughout in both strains of mice. It is therefore concluded that endogenous IFN-gamma is not responsible for upregulation of complement type 3 receptor immunomolecules in reactive microglia following nerves sec tioning. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.