To study the influence of dietary vitamins and selenium on mechanically-induced osteoarthritis (OA) and the expression of antioxidative enzymes in male STR/1N and Balb/c mice. Male STR/1N mice are prone to develop OA caused by a varus deformity-induced mechanical overload of the medial tibial plateau.
After 12 months of feeding (special diet supplemented with the vitamins E, C, A, B6, B2, and selenium) serial histological sections of the knee joints were evaluated for development of osteoarthritic changes (grade 0-4). Serum glutathione peroxidase activity (GSH-px) was measured photometrically. Expression of antioxidative enzymes was demonstrated by immunohistochemistry.
All control STR/1N mice showed OA lesions (grade 3-4) while the special diet decreased OA incidence significantly down to approximately 65% (mostly grade 2). Even in Balb/c mice the incidence was decreased by the special diet from approximately 21% (control animals; grade 1) to approximately 14%. Serum GSH-px activity increased diet-dependently in both mouse strains but was generally higher in Balb/c mice. In both mouse strains the special diet increased the expression of GSH-px and Cu/Zn-SOD in articular cartilage while there was no expression of Mn-SOD. There was also a special diet-dependent increase in expression of GSH-px in the synovium of both mouse strains while an increase in expression of Mn-SOD and Cu/Zn-SOD could only be seen in the synovium of STR/1N mice.
A diet supplemented with vitamins/selenium might be important in prevention or therapy of mechanically induced OA. We hypothesize that free oxygen radical species might be involved in the mechanical induction of OA.