Effects of Silymarin-Loaded Polylactic-co-Glycolic Acid Nanoparticles on Osteoarthritis in Rats

Abstract

Previous studies demonstrated the beneficial effects of silymarin (SM) on the various diseases. However, the low bioavailability of SM restricted its use. In the present study, SM-loaded polylactic-co-glycolic acid nanoparticles (SM-PLGA) impacts on monoiodoacetate (MIA)-induced osteoarthritis (OA) in rats were evaluated. Encapsulation of SM in PLGA was generated by a solvent evaporation method. Knee bend score was measured on days 0, 1, 7, 14, 21 and 28. Histological changes (Mankin scoring and matrix staining) and oxidative stress through measurement of the glutathione peroxidase (GPx), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and reactive oxygen species (ROS) levels in the articular tissues were evaluated. The SM-PLGA with a particle size of 81.4 nm, a Zeta potential of − 28.3 and encapsulation efficiency of 97.5% was produced. MDA levels, ROS level, total Mankin scoring and knee bend score were significantly enhanced while matrix staining, and the level of SOD, CAT, GSH and GPx was significantly reduced in the MIA group. Matrix staining and antioxidant enzymes activity were considerably elevated, while the total Mankin scoring, knee bend score, ROS formation and MDA level were significantly decreased in the SM-PLGA group in comparison with the MIA group. The histological criteria, oxidative stress and knee bend score were significantly improved in the SM-PLGA group compared with the free SM-treated rats. This information indicates that PLGA loading effectively enhances the anti-OA effects of SM on the knee joints of rats through suppressing oxidative stress.