[Collagen content and types in oral submucous fibrosis]

Oral submucous fibrosis is a chronic disease of the oral cavity. The basic histological change which occurs is a fibroelastic transformation of the connective tissue in the laminal propria layer associated with epithelial atrophy. The etiology of the disease is uncertain, but there is a close association suggested both geographically and epidemiologically with the habitual chewing of betel nuts. The accumulation of collagen fibers increases with the severity of the disease, and the fibroblasts in the normal mucosa and in the fibrotic mucosa increased their proliferation and collagen synthesis. This can be activated by arecoline, an extract from betel nuts, as described in a recent study. In order to obtain some information about the basic characteristics of the collagen in submucous fibrosis and its correlation with the fibrotic changes, the following study was conducted. In this study, collagen was extracted from the tissues of normal mucosa, normal skin and oral submucous fibrosis with pepsin and disodium hydroxyphosphate. The amino acid compositions of collagen, collagen content, types and their ratios were measured and analyzed. The results indicated that the characteristics of collagen in normal mucosa and skin were similar in content (normal mucosa: 111.8 + 31 micrograms/mg; normal skin: 131.4 + 56.4 micrograms/mg), amino acid compositions, types (I, III, V), and ratios of different types (III/I: normal mucosa: 0.119 + 0.03; normal skin: 0.187 + 0.046, V/I: 0.024 + 0.01; 0.0036 + 0.01). Collagen content in the advanced group with oral submucous fibrosis (221.6 + 58.2 micrograms/mg) was higher than that of the normal mucosa group (111.8 + 31 micrograms/mg) and the moderate group with oral submucous fibrosis (107.1 + 37.8 micrograms/mg) by a significant difference. Put no difference occurred between normal mucosa and moderate group with oral submucous fibrosis. The collagen of normal skin, normal mucosa and oral submucous fibrosis (both the advanced & moderate groups) had similar amino acid compositions, except that the presence of hydroxyproline, proline, and glycine were less in oral submucous fibrosis. The conversion factors for determining the total collagen, done by measuring the concentration of hydroxyproline, were 10.15 for oral submucous fibrosis, 9.21 for normal skin, and 8.52 for normal mucosa. Normal skin, normal mucosa, and oral submucous fibrosis have the same collagen types (I, III, V). The ratios of type III to type I collagen and type V to type I were compared between every two groups and the results showed no significant difference.(ABSTRACT TRUNCATED AT 400 WORDS)