title: Laminin-induced autoimmune myositis in rats.
abstract: The present study aimed to examine if immunization with laminin causes myositis in rats and whether the pathologic findings mirror human polymyositis and dermatomyositis. Rats were immunized with an emulsion of laminin and complete Freund's adjuvant. As a result, muscle fiber necrosis with infiltrating macrophages was frequently observed and mononuclear cells were observed in the endomysium. These mononuclear cells were composed of CD4+ cells, CD8+ T cells, and macrophages. CD4+ cells and CD8+ T cells were mainly located in the endomysium, whereas a large number of macrophages were located in the endomysium and infiltrating muscle fibers. A small number of B cells, detected by immunohistochemical staining, were mainly located in the perimysium. The nonnecrotic muscle fiber to which CD4+ T cells, CD8+ T cells, and perforin+ cells adhered was negative for antimerosin and antidystrophin antibodies. Muscle fiber necrosis in rats immunized with laminin may occur after denaturation of basement membrane proteins. In conclusion, the immunization with laminin induces moderate to severe myositis. We suggest that laminin may be an important antigen for connective tissue diseases such as polymyositis and dermatomyositis.
authors.affiliation: School of Health Sciences, Nagasaki University, Nakasaki, Japan.
authors.forename: Jiro
authors.initials: J
authors.lastname: Nakano
authors.forename: Toshiro
authors.initials: T
authors.lastname: Yoshimura
authors.forename: Minoru
authors.initials: M
authors.lastname: Okita
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Motomura
authors.forename: Shintaro
authors.initials: S
authors.lastname: Kamei
authors.forename: Hidenori
authors.initials: H
authors.lastname: Matsuo
authors.forename: Katsumi
authors.initials: K
authors.lastname: Eguchi
mesh_terms: D000818:Animals; D001323:Autoantibodies / Q000097:blood; D015153:Blotting, Western; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D005260:Female; D005620:Freund's Adjuvant / Q000633:toxicity; D007150:Immunohistochemistry; D007797:Laminin / Q000276:immunology* / Q000633:toxicity; D018482:Muscle, Skeletal / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D009336:Necrosis / Q000139:chemically induced / Q000473:pathology; D020721:Nervous System Autoimmune Disease, Experimental / Q000139:chemically induced* / Q000276:immunology* / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D001323:Autoantibodies; D007797:Laminin; D005620:Freund's Adjuvant