title: Peripheral formalin injection induces unique spinal cord microglial phenotypic changes.
abstract: Microglia are resident immune cells of brain and activated by peripheral tissue injury. In the present study, we investigated the possible induction of several microglial surface immunomolecules in the spinal cord, including leukocyte common antigen (LCA/CD45), MHC class I antigen, MHC class II antigen, Fc receptor, and CD11c following formalin injection into the rat's hind paw. CD45 and MHC class I were upregulated in the activated microglia, which was evident on day 3 with the peak expression on day 7 following peripheral formalin injection. There was a very low basal expression of MHC class II, CD11c, and the Fc receptor, which did not change after the formalin injection. These results, for the first time, indicate that peripheral formalin injection can induce phenotypic changes of microglia with distinct upregulation of CD45 and MHC class I antigen. The data suggest that phenotypic changes of the activated microglia may be a unique pattern of central changes following peripheral tissue injury.
authors.affiliation: Center for TMD & Orofacial Pain, Peking University School & Hospital of Stomatology, Beijing 100081, People's Republic of China. kqkyfu@bjmu.edu.cn
authors.forename: Kai-Yuan
authors.initials: KY
authors.lastname: Fu
authors.forename: Yong-Hui
authors.initials: YH
authors.lastname: Tan
authors.forename: Backil
authors.initials: B
authors.lastname: Sung
authors.forename: Jianren
authors.initials: J
authors.lastname: Mao
mesh_terms: D000818:Animals; D039481:CD11b Antigen / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D004202:Disinfectants / Q000008:administration & dosage*; D005557:Formaldehyde / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008297:Male; D008840:Microfilament Proteins; D017628:Microglia / Q000187:drug effects*; D010641:Phenotype; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000166:cytology* / Q000187:drug effects; D013997:Time Factors
chemical_list: C100745:Aif1 protein, rat; D039481:CD11b Antigen; D002135:Calcium-Binding Proteins; D004202:Disinfectants; D000949:Histocompatibility Antigens Class II; D008840:Microfilament Proteins; D005557:Formaldehyde; D017493:Leukocyte Common Antigens