Altered distribution of type I collagen mRNA in periodontal disease.

Earlier studies on collagen metabolism in the periodontium have suggested that periodontal disease is associated with reduced amounts of type I collagen in the pocket walls, and with an overall increase in collagen synthesis. In this study we analyzed gingival biopsies of patients suffering from adult type chronic periodontal disease by in situ hybridization, which permitted localization of fibroblasts containing different amounts of proa(I) collagen mRNA. The results showed that expression of type I collagen mRNA is reduced in the vicinity of periodontal pockets and dental plaque. Deeper in the connective tissue, high levels of proa(I) collagen mRNA were observed particularly around inflammatory cell infiltrates which may contribute to the fibrotic reaction observed. In all areas studied the levels of type I collagen mRNA in periodontal fibroblasts varied considerably, supporting previous views about their heterogeneity.