The effect of immobilization on the types of collagen synthesized in periarticular connective tissue.

The distribution of collagen types was studied in control and immobilized periarticular connective tissue to test the hypothesis that inflammatory tissue is the basis of the contracture process. The hypothesis derives from the fact that Type III collagen is prominent in inflammatory processes. The content of Type I and Type III collagen was determined by standard differential salt precipitation of the pepsin solubilized collagen, followed by resolution of the subunits on CM-cellulose. Analysis of the peptide fragments produced by cyanogen bromide was performed and their distribution determined by SDS gel electrophoresis. The collagen of control and immobilized periarticular connective tissue proved to be entirely Type I. Type III was not present. The periarticular connective tissue contracture process, therefore, is different from the intraarticular process in which fibrofatty connective tissue proliferation is prominent.