IMMUNOHISTOCHEMICAL EXAMINATION ON THE LOCALIZATION OF MACROPHAGES AND PLASMA-CELLS IN INDUCED RAT PERIAPICAL LESIONS

To investigate the role of plasma cells and macrophages in the develop ment of periapical lesions, we immunohistochemically examined the dist ribution of these inflammatory cells in experimental induced rat peria pical lesions after pulpectomy. The number of ED1-positive mononuclear cells increased rapidly, reached a plateau which remained stable betw een days 10 and 60, and subsequently decreased. Immunoglobulin (Ig)-be aring plasma cells appeared after 60 days, and, of these, IgG-bearing plasma cells were predominant after 90 days. The radiographic and hist opathological findings indicated the development of bone destruction a t 10 days which continued until 60 days; tissue repair began to take p lace after 90 days. The results suggested that macrophages had a close relation to bone destruction and that plasma cells might participate in tissue repair rather than the development of periapical lesions.