Expression of β-defensin-4 in "an in vivo and ex vivo model" of human osteoarthritic knee meniscus

Purpose: To investigate, for the first time, the expression of β-defensins-4, by immunohistochemistry and western blotting, in OA meniscus versus control meniscus, thus providing new insights into the physiological processes of meniscus repairing. Method: β-defensins-4 was studied in vivo, in knee osteoarthritic menisci obtained from 30 patients (20 men and 10 women) who underwent isolated arthroscopic partial medial or lateral meniscectomy, and in vitro on fibrochondrocyte cells from human OA knee menisci. The study was conducted using morphological, immunohistochemical, and Western blot analysis. Results: The histological results demonstrated structural alterations and cracks of OA menisci accompanied by a very strong β-defensin-4 immunohistochemical staining. The Western blot analysis confirmed also a strong expression of β-defensin-4 in OA fibrochondrocyte cells. Conclusion: The present study suggests an activation of β-defensin-4 induction, in human knee meniscus induced by the OA inflammatory process. It may represent an endogenous antibiotic defense mechanism accompanied by an intrinsic effort of tissue remodeling in OA articular joints. In conclusion, the present paper suggests the clinical relevance of β-defensin-4 in the prospective of future alternative medical treatment for OA. © 2011 Springer-Verlag.