Abstract: BACKGROUND: Preliminary studies have demonstrated that Shaoyang Shengguo Fang can alleviate joint cartilage degeneration and promote cartilage repair, but its specific mechanism for alleviating knee osteoarthritis symptoms remains unclear. The Wnt/β-catenin pathway and oxidative stress play crucial roles in maintaining articular cartilage homeostasis.
OBJECTIVE: To investigate the molecular mechanisms by which Shaoyang Shenggu Fang regulates the Wnt/β-catenin pathway to inhibit oxidative stress in cartilage and thereby delay cartilage aging in a rat model of knee osteoarthritis.
METHODS: Thirty-two Sprague-Dawley rats were randomly divided into four groups: a blank control group, a model group, a Western medicine group, and a Chinese medicine group. Animal models of knee osteoarthritis were established in all groups except for the blank control group by transecting the anterior cruciate ligament and resecting the anterior horn of the medial meniscus. At 28 days after modeling, the Chinese medicine group was administered a concentrated Shaoyang Shenggu Fang at 16 g/(kg·d) by gavage, the western medicine group was administered glucosamine hydrochloride solution at 4 mL/d by gavage, and the blank control group and model group were administered the same volume of normal saline by gavage. Four weeks after the start of treatment, hematoxylin-eosin staining and safranin O-fast green staining were used to assess the degree of cartilage injury and degeneration in the rat knee joints. ELISA was used to measure the levels of inflammatory factors and oxidative stress markers in rat serum. Western blot assay was used to determine the expression levels of p21Cip1, p16INK4a proteins, and Wnt signaling pathway-related proteins in rat knee cartilage.
RESULTS AND CONCLUSION: (1) Compared with the model group, the Western medicine group and the Chinese medicine group showed significant improvement in cartilage defects, cartilage layer thinning, and density decrease in rats, with a significant reduction in Mankin scores (P < 0.05). (2) Compared with the model group, the serum levels of interleukin-1β, tumor necrosis factor-α, and interleukin-6 in the Western medicine group and  Chinese medicine group were significantly reduced (P < 0.05), the serum levels of superoxide dismutase and glutathione peroxidase were significantly increased, and malondialdehyde content was significantly decreased (all P < 0.05). In the Chinese medicine group, the expression levels of p21Cip1, p16INK4a, and Wnt5a proteins in the Chinese medicine group were significantly decreased (P < 0.05 and P < 0.01), the expression levels of β-catenin and C-Myc protein expression levels were decreased (P < 0.05), while the expression level of glycogen synthase kinase 3β protein significantly increased (P < 0.05). (3) To conclude, Shaoyang Shenggu Fang can significantly improve the inflammation and cartilage aging in rats with knee osteoarthritis, and its mechanism may be through the Wnt/β-catenin pathway to inhibit oxidative stress levels in cartilage and delay articular cartilage aging.

Key words: knee osteoarthritis, Shaoyang Shenggu Fang, oxidative stress, inflammatory factors, Wnt/β-catenin signaling pathway, chondrocyte aging, rats