Fig. 4
From: Inflammatory profiles in canine intervertebral disc degeneration
Representative histological images of the annulus fibrosus (AF) of intervertebral discs (IVDs) graded according to Pfirrmann stained with a COX-2 antibody and counterstained with hematoxylin. a. The dorsal AF of a non-degenerated Pfirrmann grade 1 IVD consisted of well-organized lamellae with COX-2 negative spindle-shaped fibroblasts (asterisks). b. In the dorsal AF of a degenerated Pfirrmann grade IV IVD lamellar organization was lost and COX-2 negative chondrocytes (arrowheads) as well as COX-2 positive chondrocytes (arrows) were present. c. The dorsal AF of a Pfirrmann grade V IVD consisted of COX-2 negative chondrocytes (arrowheads), whereas COX-2 positive macrophages (open arrows) were situated in the dorsal ligament