stigmasterol and Osteoarthritis

Osteoarthritis (OA) is the most prevalent joint disease predominantly characterized by inflammation which drives cartilage destruction. Mesenchymal stem cells-condition medium (MSC-CM) or the secretome is enriched with bioactive factors and possesses anti-inflammatory and regenerative effects. The present study aimed at evaluating the effects of combining MSC-conditioned medium with stigmasterol compared with the individual treatments in alleviating interleukin-1 beta (IL-1β)-induced inflammation in rat chondrocytes. Stigmasterol is a phytosterol exhibiting anti-inflammatory effects. IL-1β (10 ng/ml) was used to induce inflammation and mimic OA in-vitro in primary rat articular chondrocytes. The IL-1β-stimulated chondrocytes were treated with MSC-CM, stigmasterol, and a combination of MSC-CM and stigmasterol for 24 h. Cell viability was measured using MTT assay. Protein expression of inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), collagen II (COL2A1) and matrix metalloproteinase (MMP)-13 were evaluated by immunofluorescence. Gene expression levels of MMP-3, MMP-13 and A Disintegrin-like and Metalloproteinases with Thrombospondin Motifs (ADAMTS)-5 were measured using qRT-PCR. NF-κB signaling pathway was studied using western blotting. A significant reduction in the expression of iNOS, IL-6, MMP-3, MMP-13 and ADAMTS-5, and a significant increase in COL2A1 expression was observed in the rat chondrocytes across all the treatment groups. However, the combination treatment of MSC-CM and stigmasterol remarkably reversed the IL-1β-induced pro-inflammatory/pro-catabolic responses to near normal levels comparable to the control group. The combination treatment (MSC-CM + stigmasterol) elicited a superior anti-inflammatory/anti-catabolic effect by inhibiting the IL-1β-induced NF-κB activation evidenced by the negligible phosphorylation of p65 and IκBα subunits, thereby emphasizing the benefit of the combination therapy over the individual treatments.

Topics: Animals; Anti-Inflammatory Agents; Chondrocytes; Combined Modality Therapy; Disease Models, Animal; Female; Inflammation; Interleukin-1beta; Mesenchymal Stem Cells; NF-kappa B; Osteoarthritis; Rats; Rats, Wistar; Secretome; Stigmasterol

Stigmasterol has been shown exhibit anti-osteoarthritic properties in vitro studies. However, the in vivo effects of stigmasterol on cartilage are still unclear. This study investigated the anti-osteoarthritic properties of stigmasterol on cartilage degradation in a rabbit model of osteoarthritis (OA). Twenty rabbits underwent bilateral anterior cruciate ligament transection (ACLT) to induce OA. Five rabbits were used as normal control. Two weeks after operation, the rabbits were randomly divided into two groups. Each group of 10 rabbits received intra-articular injection with 0.3 ml of stigmasterol in left knees and vehicle in right knees, once weekly. Group 1 was killed 6 weeks after ACLT and 2 were sacrificed 9 weeks after ACLT. The knee joints were assessed by gross morphology, histology and gene expression analysis. We found that expression of genes encoding matrix metalloproteinases (MMPs) was significantly higher while tissue inhibitors of metalloproteinase (TIMP)-1 was significantly lower in the both joints of the two OA groups compared to normal controls. Stigmasterol reduced the cartilage degradation as assessed by histological analysis and markedly suppressed MMPs expression both in group 1 and group 2. Our results suggest that stigmasterol may be considered as a possible therapeutical agent in the treatment of OA.

Topics: Animals; Cartilage; Disease Models, Animal; Gene Expression Regulation; Humans; Knee Joint; Matrix Metalloproteinases; Osteoarthritis; Rabbits; Stigmasterol; Tissue Inhibitor of Metalloproteinase-1