Involvement of the p38 MAPK–NF-κB Signal Transduction Pathway and COX-2 in the Pathobiology of Meniscus Degeneration in Humans

Meniscal tears are attributed to either trauma or degeneration processes. Clinical data suggest that meniscal degeneration (MD) is associated with knee osteoarthritis; however, the molecular events underpinning the pathogenesis of MD in humans remain elusive. Here we immunohistochemically examined the expression of p38 MAPK, its phosphorylated/activated form (p-p38), its target NF-κB (p50–p65 dimer), and COX-2 in ruptured menisci and investigated their involvement in MD development. Our findings demonstrate increased expression of the p38–NF-κB axis elements and COX-2 in disintegrated fibrocartilage, suggesting a role of these molecules in the pathobiochemistry of MD and consequential rupture