Fig. 4.

Sagittal osteochondral section obtained from the third carpal bone of the equine carpal osteochondral fragment model 70 days after fragment induction, stained with monoclonal antibody 6a8 for lubricin (A) and with Safranin O Fast Green for sulfated proteoglycans (B). (A) Lubricin immunoreaction is significantly increased within the fibrocartilaginous repair tissue articulating with the radial carpal bone (RCB) fragment (A, left two images). Lubricin localization is primarily confined to areas devoid of Safranin O staining (A, B second image from the left). Lubricin intensely stains a region of fissured and fibrillated cartilage (A, second image from right) demonstrating significant cell loss and loss of proteoglycan (B, second image from right) as compared to staining of the superficial 2–3 cell layers in adjacent healthy cartilage distant from the RCB fragment (A, B rightmost images).