Astroglial reaction during the early phase of acute lead toxicity in the adult rat brain

The developing nervous system is susceptible to lead (Pb) exposure but less is known about the effect of this toxic agent in adult rat brain, Since as trocytes serve as a cellular Pb deposition site, it is of importance to inv estigate the response of astroglial cells in the adult rat brain in a model of acute lead exposure (25 mg/kg b.w. of lead acetate, i.p. for 3 days). A n increased immunoreactivity of glial fibrillary acidic protein (GFAP) on W estern blots was noticeable in fractions of astroglial origin-glial plasmal emmal vesicles (GPV) and in homogenates from the hippocampus and cerebral c ortex but not in the cerebellum. The features of enhanced astrocytic reacti vity (i.e. large accumulation of mitochondria, activated Golgi apparatus an d increment of gliofilaments) were observed in electron microscopy studies in the same tissues. Total glutathione levels increased both in GPV fractio ns and in brain homogenates-in the cerebellum (120% above control) and in h ippocampus (30% above control). The results of current studies indicate tha t acute lead exposure is accompanied by astrocyte activation connected with the presence of the enhanced expression of GFAP. It may indicate lead-indu ced neuronal injury. At the same time, a regional enhancement of detoxicati ve mechanisms (GSH) was noticed, suggesting activation of astrocyte-mediate d neuroprotection against toxic Pb action. (C) 2001 Elsevier Science Irelan d Ltd. All rights reserved.