Boiogito, a Japanese Traditional Herbal Medicine, Inhibits the Osteoclast Differentiation and Proliferation in the Subchondral Bone of an In Vivo Knee Osteoarthritis Rat Model

Abstract

Boiogito (BO), a Japanese traditional herbal medicine, has been reported to prevent knee osteoarthritis (KOA) development in in vivo studies. In the early stage of KOA, osteoclasts proliferate in the subchondral bone. This study aimed to investigate the preventive effect of BO on osteoclast proliferation, which remains unclear, in a KOA-induced rat model. KOA was induced in 12-week-old male Wistar rats using surgical destabilization of the medial meniscus (DMM). BO was mixed with powdered chow, applying 1%, 3%, and 5% of the total feed, and administered to KOA-induced rats. The rats were divided into 6 groups: control, sham, DMM, DMM + BO 1%, DMM + BO 3%, and DMM + BO 5%. Rotarod tests were performed each week to assess the locomotor function, and the right knees were harvested 28 days after surgery for histological analysis. Oral administration of BO significantly inhibited the decrease in the latency to fall off in the rotarod test, which was aggravated in the DMM group. Furthermore, KOA development was significantly prevented in the BO-administrated groups as assessed by the Osteoarthritis Research Society International score. The number of multinucleated activated osteoclasts in the subchondral bone was decreased in the BO-treated groups, which was increased in the DMM group. Therefore, oral administration of BO may reduce articular cartilage degeneration, osteoclast differentiation and proliferation in the KOA patients.