The determination of apoptosis rates on articular cartilages of ovariectomized rats with and without alendronate treatment

Abstract

Osteoporosis (OP) is a major health problem characterized by compromised bone strength. Osteoarthritis (OA) is a joint disease that progresses slowly and is characterized by breakdown of the cartilage matrix. Alendronate (ALN), a nitrogencontaining bisphosphonate (BIS), inhibits bone loss and increases bone mineralization, and has been used clinically for the treatment of OP. It is still controversial whether BIS is effective in inhibiting the progression of OA. Chondrocyte apoptosis has been described in both human and experimentally induced OA models. In our study we aimed to detect whether ALN could protect articular cartilage from degeneration and reduce apoptosis rates in experimentally OA induced rats. For this rats were ovariectomized (ovex), nine weeks after operation rats were injected 30 μg/kg/week ALN subcutaneously for six weeks. After six weeks articular cartilages were obtained. We did Safranin O staining and Mankin and Pritzker scorings to evaluate degeneration and investigated the expressions of p53, cleaved caspase 3, Poly ADP-ribose (PAR), Poly ADP-ribose polymerase 1 (PARP 1), and applied TUNEL technique to determine apoptotis rates. We found a significant decrease in glycosaminoglycan (GAG) amount and increased apoptosis which indicates damage on articular cartilages of ovex rats. GAG amount was higher and apoptosis rate was lower on articular cartilages of ALN treated ovex rats compared to the ovex group. In contrary to studies showing that early ALN treatment has a protective effect, our study shows late ALN treatment has a chondroprotective effect on articular cartilage since we treated rats nine weeks after ovariectomy