Tanshinone IIA Facilitates Efficient Cartilage Regeneration under Inflammatory Factors Caused Stress via Upregulating LncRNA NEAT1_2

(1) Background: Osteoarthritis (OA) is a crippling condition characterized by chondrocyte dedifferentiation, cartilage degradation, and subsequent cartilage defects. Unfortunately, there is a lack of effective medicines to facilitate the repair of cartilage defects in OA patients. In this study, we investigated the role of lncRNA NEAT1_2 in maintaining the chondrocyte phenotype and identified tanshinone IIA(TAN) as a natural medicine that enhances NEAT1_2 levels, resulting in efficient cartilage regeneration under inflammatory cytokines. (2) Methods: The transcriptional levels of NEAT1_2 and cartilage phenotype-related genes were identified by RT-qPCR. The siRNA interference approach was utilized to silence NEAT1_2; the Alamar Blue assay was performed to determine chondrocyte viability under inflammatory conditions. To evaluate the concentrations of collagen type II and glycosaminoglycans distributed by chondrocytes in vitro and in vivo, immunohistochemical staining and Safranin O staining were used. (3) Results: IL-1β suppresses NEAT1_2 and genes related to the chondrocytic phenotype, whereas TAN effectively upregulates them in a NEAT1_2-dependent manner. Consistently, TAN alleviated chondrocyte oxidative stress inhibited cartilage degradation by modulating the relevant genes and promoted efficient cartilage regeneration in vitro and in vivo when chondrocytes are exposed to inflammatory cytokines. (4) Conclusions: TAN enhances the expression of NEAT1_2 inhibited by IL-1β and affects the transcription of chondrocytic phenotype-related genes, which promotes cartilage regeneration in an inflammatory environment.