FGF-2 and S100β immunoreactivities increase in reactive astrocytes, but not in microglia, in ascending dopamine pathways following a striatal 6-OHDA-induced partial lesion of the nigrostriatal system

Authors

  • G. Chadi,

    Corresponding author
    1. Laboratory of Neuroregeneration, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, Avenida Prof. Lineu Prestes 2415, 05508-900-São Paulo, Brazil
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  • V.C. Gomide

    1. Laboratory of Neuroregeneration, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, Avenida Prof. Lineu Prestes 2415, 05508-900-São Paulo, Brazil
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Corresponding author. Tel.: +55 11 3090 7366; fax: +55 11 3091 7366. gerchadi@usp.br, http:www.icb.usp.brneuron

Abstract

Partial lesions were induced in rat midbrain dopamine ascending pathways by intrastriatal injection of 6-hydroxydopamine (6-OHDA), and after two weeks changes were observed in the immunoreactivities of S100β, a calcium-binding protein, and basic fibroblast growth factor (FGF-2), which is neurotrophic. Semiquantitative microdensitometric image analysis revealed increased intensities of FGF-2 and S100β immunostaining in putative glial profiles of the ipsilateral neostriatum, pars compacta (SNc) and reticulata (SNr) of the substantia nigra and ventral tegmental area (VTA). Double immunofluorescence and immunoperoxidase procedures, using antibodies against glial fibrillary acidic protein and OX-42, showed that these increased immunoreactivities were restricted to reactive astrocytes; they were not observed in reactive microglia. These results indicate that reactive astrocytes may exert paracrine trophic actions through S100β and FGF-2 in the midbrain dopamine ascending pathways after striatal 6-OHDA treatment. Interactions between S100β and FGF-2 may be relevant to neuronal maintenance and repair following dopamine injury.

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