Pathological dynamics of activated microglia following medial forebrain bundle transection

摘要: To elucidate the role and pathological dynamics of activated microglia, this study assessed phagocytic, immunophenotypic, morphological, migratory properties microglia in medial forebrain bundle (MFB) axotomized rat brain. Activated were identified using two different monoclonal antibodies: ED1 for phagocytic activity OX6 major histocompatibility complex (MHC) class II. Phagocytic characterized by ED1-immunoreactivity or ED1- OX6-immunoreactivity, appeared MFB substantia nigra (SN) as early 1–3 days post-lesion (dpl), when there was no apparent loss SN dopamine (DA) neurons. Thereafter, a great number selectively adhered to degenerating axons, dendrites DA neuronal somas SN. This followed significant these fibers nigral Activation into stage most pronounced between 14∼28 dpl gradually subsided, but persisted until 70 dpl, last time point examined. expression preceded MHC II microglia. All sticking neurons showed ramified form with enlarged thickened processes. They recruited SNc from cranial, dorsal ventral aspects along various structures finally stuck SNc. Characteristic rod-shaped white matter thought migrate long distance. The present strongly suggests that undergoing delayed neurodegeneration may be phagocytosed numerous at sites where specific surface signals are exposed diffusible molecules released. © 2005 Wiley-Liss, Inc.