Connective tissue composition and collagen synthesis in diseased and normal gingiva of adult dogs with spontaneous periodontitis

Abstract

In beagles, chronic spontaneous periodontitis is characterized clinically by a gradual conversion of the normal marginal gingival tissue to acutely inflamed hyperplastic granulation tissue; fibrosis as seen frequently in man does not occur. While still relatively small, the granulations contained about 6-fold less collagen than normal gingival tissue and a dense inflammatory infiltrate. Of the total cell population, fibroblasts made up only 5 per cent, lymphocytes 44 per cent, plasma cells 43 per cent and polymorphonuclear neutrophils (PMNs) 5 per cent. In the large granulations associated with advanced stages of the disease (i.e. pockets, bone loss), the collagen content was about 4.5-fold lower than in normal tissue and the cell composition was 12 per cent fibroblasts, 20 per cent lymphocytes, 40 per cent plasma cells, and 21 per cent PMNs. Altered fibroblasts, as seen in the early lesion in man and other animal species, were not observed. Synthesis of both protein and collagen was much greater in cultures containing the diseased hyperplastic tissues than in those containing normal tissue; the fibroblast density was similar in the two types of tissue. The proportion of labelled protein in the culture medium was greater in the cultures of diseased tissue than in those of normal tissue.