QUANTITATIVE-ANALYSIS OF CYANOGEN BROMIDE-CLEAVED PEPTIDES FOR THE ASSESSMENT OF TYPE-I-TYPE-II COLLAGEN RATIOS IN EQUINE ARTICULAR REPAIR TISSUE

Cyanogen bromide was used to solubilise and specifically fragment purified equine Type I and II collagen and equine articular surface repair tissue. The resultant peptides were separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and quantified by densitometric scanning. Measurement of the relative amounts of the peptides alpha 2(I) CB3, 5 and alpha 1(II)CB10 provided an accurate method of establishing the ratio of Type I to Type II collagen in mixtures of purified equine collagens. The method was sensitive to 6% Type II collagen when the band areas were corrected for peptide molecular weight and the number of chains in the parent tropocollagen molecule which contain that particular peptide. Use of this technique showed that repair tissue in full thickness osteochondral defects in the dorsodistal margins of the intermediate carpal bones of ponies did not contain detectable amounts of Type II collagen 11 weeks after defect induction.