MTOR and osteoarthritis: Subsequently, the same group demonstrated that in rat primary chondrocytes treated with IL-1β (i.e., in an in vitro model of osteoarthritis), O3 improved autophagy by activating the pathway of peroxisome proliferator-activated receptor γ (PPARγ)/mechanistic target of rapamycin (mTOR) (both involved in autophagy regulation) [158].