LOCALIZED CELLULAR INFLAMMATORY RESPONSES TO SUBCUTANEOUSLY IMPLANTEDDENTAL MERCURY

Previous reports have demonstrated mercury accumulation and toxicity i n oral tissues following exposure to mercury vapor from dental amalgam restorations. in the present study, inflammatory responses to subcuta neously administered mercury were assessed histopathologically and imm unocytochemically in a rat model system. A panel of six well-character ized monoclonal antibodies specific for monocytes, macrophage subsets, T and B lymphocytes, and major histocompatibility complex (MHC) class II (la) determinants was used to quantitate alterations in mononuclea r cell subsets in situ at time intervals from 2 d to 8 wk. The results revealed acute inflammatory cell infiltration at 2 and 3 d, followed by chronic inflammation that persisted alter 8 wk. The numbers of mono cytes, resident macrophage subsets, and mononuclear cells expressing l a antigen were significantly different from control tissues at 1-2 wk. The numbers of resident macrophages remained significantly higher eve n after 8 wk. These data showed that in situ mercury accumulation can lead to altered expression of MHC class II determinants with persisten t chronic inflammation and shifts in mononuclear cell subpopulations.