title: Glial expression of small heat shock proteins following an excitotoxic lesion in the immature rat brain.
abstract: Heat shock proteins (HSPs) are chaperones induced under pathological conditions and involved in protein stabilization and cellular protection. In this study, we have evaluated the expression pattern of the glial cell-related HSP27, HSP32, and HSP47 following an excitotoxic lesion in the immature rat brain. Postnatal day 9 rats received an intracortical injection of N-methyl-D-aspartate and tissue was processed immunohistochemically for HSPs and double labeling using astroglial and microglial markers. HSP expression was quantified by image analysis. Excitotoxic damage caused primary cortical degeneration and secondary damage in the corresponding thalamus. In the injured cortex, reactive microglia/macrophages expressed HSP32 from 10 h until 14 days postlesion (PL), showing maximal levels at days 3-5. In parallel, most cortical reactive astrocytes showed expression of HSP47 from 10 h until 14 days PL and a population of them also displayed HSP27 labeling from 1 day PL. In addition, some cortical reactive astrocytes showed a temporary expression of HSP32 at day 1. In general, astroglial HSP expression in the cortex achieved maximal levels at days 3-5 PL. In the damaged thalamus, HSP32 was not significantly induced, but reactive astrocytes expressed HSP47 and some of them also HSP27. Thalamic astroglial HSP induction was transient, peaked at 5 days PL and reached basal levels by day 14. The injury-induced expression of HSP32, HSP27, and HSP47 in glial cells may contribute to glial cell protection and adaptation to damage, therefore playing an important role in the evolution of the glial response and the excitotoxic lesion outcome. HSP32 may provide antioxidant protective mechanisms to microglia/macrophages, whereas HSP47 could contribute to extracellular matrix remodeling and HSP27 may stabilize the astroglial cytoskeleton and participate in astroglial antioxidant mechanisms.
authors.affiliation: Unit of Histology, Department of Cell Biology, Physiology and Immunology, School of Medicine, Autonomous University of Barcelona, Bellaterra, Spain. laia.acarin@uab.es
authors.forename: Laia
authors.initials: L
authors.lastname: Acarin
authors.forename: Jaume
authors.initials: J
authors.lastname: Paris
authors.forename: Berta
authors.initials: B
authors.lastname: González
authors.forename: Bernardo
authors.initials: B
authors.lastname: Castellano
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D001921:Brain / Q000254:growth & development / Q000378:metabolism* / Q000503:physiopathology; D001930:Brain Injuries / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D002540:Cerebral Cortex / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005911:Gliosis / Q000378:metabolism*; D055551:HSP27 Heat-Shock Proteins; D050958:HSP47 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism; D051547:Heme Oxygenase-1; D008264:Macrophages / Q000378:metabolism; D008297:Male; D017628:Microglia / Q000378:metabolism; D016202:N-Methylaspartate / Q000494:pharmacology; D009363:Neoplasm Proteins / Q000378:metabolism; D009410:Nerve Degeneration / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D020318:Rats, Long-Evans; D013312:Stress, Physiological / Q000378:metabolism / Q000503:physiopathology; D013788:Thalamus / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D015854:Up-Regulation / Q000502:physiology
chemical_list: D005904:Glial Fibrillary Acidic Protein; D055551:HSP27 Heat-Shock Proteins; D050958:HSP47 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C486114:Hspb1 protein, rat; D009363:Neoplasm Proteins; C494662:Serpinh1 protein, rat; D016202:N-Methylaspartate; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1