Effects of dental plaque on the production and release of lysosomal hydrolases by macrophages in culture

Abstract

Mouse peritoneal macrophages, obtained by lavage and cultured for 24–72 hr in media 199, were exposed to several concentrations of dead, freeze-dried plaque for various time periods. The presence of plaque concentrations of 1–20 μg/ml led to a 3–4-fold increase in cell size and in the content of lactate dehydrogenase and leucine-2-naphthylamidase, and to a doubling in the levels of beta-glucuronidase. These are features of cell activation. Furthermore, plaque induced a marked and selective release of lysosomal enzymes into the culture media. Up to 80 per cent of the total hydrolase present was released. If a similar release of hydrolases from macrophages occurs within the gingiva in response to plaque, wide-spread long-term tissue damage would be expected.