Age-Related Differences in LPS-Induced BDNF and iNOS Expression in the Substantia Nigra in Rats

Abstract

Objectives. To study the intensity of the expression of brain-derived neurotrophic factor (BDNF) and inducible nitric oxide synthase (iNOS) in glial cells in the substantia nigra of the brain in rats of different ages in health and in neuroinflammation. Materials and methods. Experiments were performed on 36 male Wistar rats – 18 young animals with body weight 250–300 g and 18 old animals with body weight 380–420 g. Immunohistochemical studies detected the study markers on cryostat sections in astro- and microgliocytes in the substantia nigra eight weeks after unilateral stereotaxic administration of lipopolysaccharide (LPS) into this area. Results. Significantly greater numbers of GFAP- and CD11β-positive cells (astro- and microgliocytes respectively) were seen in the substantia nigra of the brains of older rats. Age-dependent differences were seen in LPS-induced BDNF and iNOS production eight weeks after administration of endotoxin. Administration of LPS intensified the production of BDNF in astrocytes in young but not old animals, while the microgliocytes of old rats showed significant intensification of iNOS expression. Conclusions. The balance of trophic and harmful factors synthesized by glial cells in the substantia nigra of the midbrain in response to endotoxin stimulation depended on age. The glial reaction to endotoxin in young animals was protective in nature, while in old animals it increased the risk of oxidative neuron injury.