Immunohistochemistry included rabbit monoclonal anti-TNFα (diluted 1:1,000; HP8001, rabbit IG; Hycult Biotechnology BV, Uden, the Netherlands). The section of TNFα was developed with Dako EnVision + Dual Link System-HRP (DAB+) kit (Dako, Glostrup, Denmark). Counterstaining involved hematoxylin, and rabbit IgG served as negative control. Briefly, three sections from each femoral condyle and tibial plateau were scored by two investigators blinded to origin of the samples. Total and positively stained chondrocytes were counted and reported as percentages, where 100% was the maximum score.41 (link)
Osteoclast activity was observed by tartrate-resistant acid phosphatase (TRAP) staining with leukocyte acid phosphatase kits (Sigma-Aldrich Chemical Co.) following the manufacturer’s instructions. Nuclei were counterstained with Gill’s hematoxylin (Sigma-Aldrich Chemical Co.), and averages of TRAP-positive osteoclasts were calculated.25 (link)