In vitro breakdown of gingival tissue by elastase from human polymorphonuclear leukocytes An electron microscopic study

Several biopsies of human marginal gingiva were collected from clinically healthy and from slightly inflamed sites. The biopsies from one given site were divided and treated as follows: one portion was immediately fixed and used as a reference; the others were incubated for two hours either in culture medium alone, or in the same medium with different concentrations of elastase purified from human polymorphonuclear leukocytes. The biopsies were then fixed and examined by electron microscopy. It was found that elastase caused an enlargement of the intercellular spaces of the oral gingival epithelium, interruptions of the basement lamina, and loss of collagen in the underlying connective tissue. Biopsies collected from severely inflamed sites were also studied in the electron microscope. Some of the ultrastructural alterations observed in these inflamed tissues were similar to those experimentally induced by elastase.