IMMUNOHISTOCHEMICAL DISTRIBUTION OF TYPE-I, TYPE-II AND TYPE-III COLLAGENS IN THE RABBIT SUPRASPINATUS TENDON INSERTION

The collagen fibres in the area of attachment of the supraspinatus ten don to bone were studied immunohistochemically in 12 mature female New Zealand white rabbits. The labelling of type I collagen was uniformly prominent in the bone as well as in the fascicles of the tendon prope r but inconspicuously scattered in the unmineralised sind mineralised zones of the fibrocartilage. Type TI collagen, not detected in the ten don proper, was widespread in both zones of the fibrocartilage. Type I II collagen, on the other hand, appeared to be confined mainly to the zone of unmineralised fibrocartilage, in addition to its presence in t he endotenon of the tendon proper. The region of the tidemark failed t o show immunostaining for any of the collagen fibre types. In conclusi on, this study demonstrates that, although all the principal fibrous c ollagen types are constituents of the supraspinatus tendon at its atta chment site, the distribution pattern of immunolabelling varies from z one to zone.