Fibroblast cytotoxicity associated with plasma cells and lymphocytes in chronic periodontitis lesions in rats.

INTERDENTAL PERIODONTITIS LESIONS in rats 20 to 27 months of age were found to contain large aggregations of plasma cells and lymphocytes. Fibroblasts in areas of dense immunocyte infiltration appeared damaged. The close juxtaposition of both plasma cells and lymphocytes to the altered fibroblasts suggests that a cytotoxic effect of immunocyte origin might be a significant element in connective tissue alteration in advanced periodontitis lesions in older rats. At the ultrastructural level, the damaged fibroblasts exhibited alteration of the nucleus, loss of cytoplasmic content including microfilaments and microtubules, swelling and degeneration of mitochondria and Golgi vesicles and cisternae. Dilation of the rough endoplasmic reticulum, including the perinuclear cisterna, along with vesiculation of the cytoplasmic membranes, suggests osmotic dysfunction in various cellular organelles.