Dynamic induction of the long pentraxin PTX3 in the CNS after limbic seizures: Evidence for a protective role in seizure-induced neurodegeneration

Pentraxin 3, a prototypic long pentraxin, is induced by proinflammatory sig nals in the brain. Inflammatory cytokines are rapidly induced in glia by ep ileptic activity. We show that pentraxin 3 immunoreactivity and mRNA are en hanced in the rat forebrain above undetectable control levels by limbic sei zures with a dual pattern of induction. Within 6 h from seizure onset, pent raxin 3 immunoreactivity was increased in astrocytes. Eighteen to 48 It lat er, specific neuronal populations and leucocytes were strongly immunoreacti ve only in areas of neurodegeneration. This staining was abolished when neu ronal cell loss, but not seizures, was prevented by blocking N-methyl-D-asp artate receptors. Pentraxin 3 -/- mice had a more widespread seizure-relate d neuronal damage in the forebrain than their wild-type littermates althoug h both groups had similar epileptic activity. Our results provide evidence that pentraxin 3 is synthesized in brain after seizures and may exert a protective role in seizure-induced neurodegenerat ion. (C) 2001 IBRO. Published by Elsevier Science Ltd. All rights reserved.