Bushen Qiangjin capsule inhibits the Wnt/α-catenin pathway to ameliorate papain-induced knee osteoarthritis in rat.

OBJECTIVE: To evaluate the molecular mechanism underlying the beneficial effect of Bushen Qiangjin capsule (BSQJ), a Traditional Chinese Medicine, on knee osteoarthritis (KOA). METHODS: In the present study, 32 female Sprague-Dawley rats were randomly divided into four groups: control, KOA, high-dose BSQJ (H-BSQJ), and low-dose BSQJ (L-BSQJ). After successfully establishing the KOA model by intra-articular injection of papain, H-BSQJ and L-BSQJ groups were intragastrically administered 0.243 and 0.122 g/kg BSQJ, respectively, daily for 6 weeks. At the end of the experiment, knee articular cartilage tissues of rats were collected for evaluation by hematoxylin and eosin staining, Safranin O-Fast Green staining, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. Serum interleukin-1α and tumor necrosis factor-α levels of rats were detected with an enzyme-linked immunosorbent assay method. Gene expression of Wnt-4, α-catenin, Frizzled-2, glycogen synthase kinase-3ß (GSK-3ß), cysteinyl aspartate-specific proteinases 3 and 9 (caspases 3 and 9), collagen type II alpha 1 (Col2a1), and matrix metalloproteinases 1 and 13 (MMP-1 and MMP-3) of rat knee articular cartilage was quantified by reverse transcription-quantitative polymerase chain reaction analysis. Wnt-4, α-catenin, Frizzled-2, GSK-3ß, cleaved caspase-3, and cleaved caspase-9 protein expression in rat knee articular cartilage was determined by western blot analysis. RESULTS: BSQJ obviously reduced pathological damage and matrix degradation of articular cartilage in KOA rats. Compared with the KOA group, H-BSQJ rats exhibited downregulated mRNA and protein expression of Wnt-4, ß-catenin, Frizzled-2,and caspase-3, as well as upregulated mRNA and protein expression of GSK-3α. In addition, H-BSQJ significantly increased mRNA expression of Col2a1 and decreased mRNA expression of MMP-1 and MMP-13. CONCLUSION: BSQJ exerted a beneficial effect on KOA by a mechanism involving downregulation of the Wnt/α-catenin pathway, which inhibited both cartilage extracellular matrix degradation and chondrocyte apoptosis to ameliorate KOA in rats.

The synovial fluid neuropeptide PACAP may act as a protective factor during disease progression of primary knee osteoarthritis and is increased following hyaluronic acid injection.

The correlation of serum and synovial fluid (SF) pituitary adenylate cyclase-activating polypeptide (PACAP) levels with disease progression of primary knee osteoarthritis (OA) was explored. Radiographic severity of OA was determined by Kellgren-Lawrence (K-L) grades. PACAP levels were measured by ELISA before treatment, and 4 and 8 wk following hyaluronic acid (HA) injection. Levels of IL-1ß and MMP-3 were also detected. The numeric pain scale (NPS), revised Oxford Knee Score (OKS), and American Knee Society Score (AKSS) were employed to evaluate to symptomatic severity. Receiver-operating-characteristic (ROC) curve analysis was carried out to compare the diagnostic value of PACAP, IL-1ß, and MMP-3 for the K-L grade. PACAP concentrations in SF but not serum were significantly lower in OA patients compared with controls. SF PACAP levels were negatively associated with K-L grades and higher NPS as well as worse AKSS and OKS. Further analysis demonstrated that PACAP concentration in SF was negatively correlated with expressions of IL-1ß as well as MMP-3 and may act as a marker for radiographic progression along with MMP-3. Last, we found SF PACAP levels exhibited an incremental trend after HA injection. These findings confirmed the crucial role of PACAP deficiency in the development of primary knee OA.