title: Immunohistochemical localization of cathepsins B, D and L in the rat osteoclast.
abstract: Immunohistochemical localization of cathepsins B, D and L in the osteoclasts of rat alveolar and femoral bones was investigated by using the avidin-biotin-peroxidase complex method for semithin, 1-micron-thick cryosections. Extracellular immunoreactivity for cathepsins B and L was clearly demonstrated along the bone resorption lacunae; the intensity of the extracellular immunoreactivity of cathepsin L was stronger than that of cathepsin B. However, the intracellular immunoreactivity of both cathepsins was weak compared with that of cathepsin D. The intracellular immunoreactivity of cathepsin D in the osteoclasts was clearly observed in the granules and/or vacuoles, but extracellular cathepsin D immunoreactivity was either negligible or not detected along the resorption lacunae. In the adjacent sections stained with anti-cathepsin L or D, extensive extracellular deposition of cathepsin L was found along the bone resorption lacunae, with or without osteoclasts, although the intracellular reactivity of cathepsin L was weak. This is the first morphological study in which cathepsins B and L have been demonstrated to be produced in the osteoclasts and extensively secreted into resorption lacunae, and in which cathepsin D was found to be present in the cells but scantily secreted into the lacunae. These findings suggest that cathepsins B and L directly and effectively participate in the degradation of the bone matrix.
authors.affiliation: Department of Oral Anatomy, Faculty of Dentistry, Kyushu University, Fukuoka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Goto
authors.forename: T
authors.initials: T
authors.lastname: Tsukuba
authors.forename: T
authors.initials: T
authors.lastname: Kiyoshima
authors.forename: Y
authors.initials: Y
authors.lastname: Nishimura
authors.forename: K
authors.initials: K
authors.lastname: Kato
authors.forename: K
authors.initials: K
authors.lastname: Yamamoto
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D001360:Avidin; D001710:Biotin; D001862:Bone Resorption / Q000503:physiopathology; D002401:Cathepsin B / Q000276:immunology / Q000378:metabolism; D002402:Cathepsin D / Q000276:immunology / Q000378:metabolism; D056668:Cathepsin L; D002403:Cathepsins / Q000276:immunology / Q000378:metabolism*; D003546:Cysteine Endopeptidases; D010450:Endopeptidases; D004792:Enzyme Precursors / Q000276:immunology / Q000378:metabolism; D007124:Immunoenzyme Techniques; D007150:Immunohistochemistry; D010010:Osteoclasts / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D004792:Enzyme Precursors; D001360:Avidin; D001710:Biotin; D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; D056668:Cathepsin L; C534280:Ctsl protein, rat; D002402:Cathepsin D