Nishihara Technique for the Solubilization of Collagen

Aged tendon and connective tissue contain very little tropocollagen which may be extracted by dilute solutions of neutral salts or acetic acid (Jackson and Bentley, 1960). Collagen from these tissues is usually prepared by mechanical removal of noncollagenous materials (Neuman, 1949), or by the thermal conversion of the insoluble collagen to its derived soluble gelatin (Jackson, 1957). A recent Japanese patent (No. 9295/63, Nishihara, 1963) describes the isolation of soluble collagen from ox-hide after pre-treatment of the minced tissue with oc-amylase and extraction of the collagen in dilute hydrochloric acid. This technique seems to offer great advantages over the previous methods and it has been applied successfully to the large scale isolation of soluble collagen from connective tissue obtained from normal and rheumatoid arthritic patients. Hip joint tissue used in this work was kindly provided by Mr. J. Charnley of the Wrightington Hospital, Wigan. Knee joint tissue was provided by Mr. Jack Stevens, Western Infirmary, Glasgow.