Effect Of Alendronate Sodium On Articular Cartilage Of Rat Knee Joint With Osteoporosis

Background Osteoporosis is a systemic skeletal disorder characterized by low bone mass and micro architectural deterioration of bone tissue, leading to enhanced bone fragility. Osteoarthritis is a nonspecific inflammation characterized by changes of articular cartilage and Subchondral bone osteonecrosis,Cystic degeneration, leading to increase bone density and formation of osteophyte. OP and OA often generate each other, and there is a unvarying relation between them. Bisphostates is a kind of stable analogue of pyrophosphate, it can refrain drug-induced bone resorption. Previous foreign studies reported that BPs could decrease typeⅡcollagen degradation and refrain chondrocyte apoptosis. Alendronate sodium is frequently used to treat osteoporosis, but it is not clear for it,s role on cartilage.Objective To access the effect of alendronate on articular cartilage of rat knee joint with osteoporosis.Methods Thirty-six 6-month-old female SD(Sprague-Dawley) rats were divided randomly into three groups. Rats in (OVX+NS) group and (OVX+ALEN) group were subjected to be ovariectomized, while rats in Sham group subjected to sham-operation. (OVX+ALEN) group began to receive a weekly intragastric administration of alendronate solution at a does of 36mg per kg of body weight for 4,8 and 12 weeks, in contrast, Sham group and (OVX+NS) group receive NS at the same does. After 4,8 and 12 weeks, four rats in every group are sacrificed by anesthetize excessively and tibia articular cartilage were stained with HE, toluidine blue and typeⅡcollagen immunohistochemisty; femur articular cartilage were stained with HE,AB-PAS and typeⅡcollagen immunohistochemisty. Gray scale of typeⅡcollagen immunohistochemisty sections were measured by image analyser and the thickness of articular cartilage were measured with HE sections.Result The thickness of articular cartilage in every group was chose to each other at the time of 4W, as the same as the cell count of chondrocyte . The results of four dyeing methods were not clear at the time of 4W; The thickness of articular cartilage in (OVX+NS) group were lower than (OVX+ALEN) group at the time of 8,12W(P﹤0.05); Gray scale of typeⅡcollagen immunohistochemisty of (OVX+ALEN) group were higher than (OVX+NS) group at the time of 12W(P﹤0.05).Conclusion The structure and metabolism of articular cartilage were changed under the osteoporosis circumstances and alendronate sodium can protect articular cartilage from degradation.