A biochemical study of collagen in the periodontal ligament from erupting and non-erupting bovine incisors

Abstract

The extractability of collagen in the periodontal ligament (PDL) from erupting and non-erupting bovine incisors was studied. The ligament was extracted with water, salt and acetic acid solutions. The PDL contained about equal amounts of collagen and non-collagenous proteins. The amount of collagen that could be extracted with salt-solutions was rather small and did not parallel the expected high metabolism of collagen in the PDL. It is suggested that, in the PDL, newly synthesized tropocollagen molecules mature more rapidly than in other tissues. The PDL from non-erupting incisors contained less salt-soluble collagen than that from erupting incisors. This might be due to either a lower level of fibre-remodelling or to ageing. Extraction with acetic acid yielded variable amounts of collagen. In all cases, however, it was found that acetic acid solubilized collagen much more rapidly from younger than from older tissue. The degree of cross-linking in the soluble collagen fractions from PDL, as indicated by the proportion of α- and β-components, determined by densitometer readings after electrophoresis, is the same as is reported for other tissues. It is concluded that for periodontal ligament the amount of extractable collagen provides insufficient information about the metabolism of collagen.