Schisandrae Fructus ethanol extract ameliorates inflammatory responses and articular cartilage damage in monosodium iodoacetate-induced osteoarthritis in rats

Schisandrae Fructus, the fruit of Schisandra chinensis (Turcz.) Baill., is widely used in traditional medicine for the treatment of a number of chronic diseases. Although, Schisandrae Fructus was recently reported to attenuate the interleukin (IL)-1β-induced inflammatory response in chondrocytes in vitro, its protective and therapeutic potential against osteoarthritis (OA) in an animal model remains unclear. Therefore, we investigated the effects of the ethanol extract of Schisandrae Fructus (SF) on inflammatory responses and cartilage degradation in a monosodium iodoacetate (MIA)-induced OA rat model. Our results demonstrated that administration with SF had a tendency to attenuate MIA-induced damage of articular cartilage as determined by a histological grade of OA. SF significantly suppressed the production of pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-α in MIA-induced OA rats. SF also effectively inhibited expression of inducible nitric oxide (NO) synthase and cyclooxygenase-2, thereby inhibiting the release of NO and prostaglandin E2. In addition, the elevated levels of matrix metalloproteinases-13 and two biomarkers for diagnosis and progression of OA, such as cartilage oligomeric matrix protein and C-telopeptide of type II collagen, were markedly ameliorated by SF administration. These findings indicate that SF could be a potential candidate for the treatment of OA.