Structural Characterization of Chondroitin Sulfate from Hybrid Sturgeon (Acipenser schrenckii × Huso dauricus) Cartilage and Its Alleviating Effect on Osteoarthritis.

Objectives

Given that the structure-activity relationship between sturgeon chondroitin sulfate (S-CS) and the alleviation of osteoarthritis (OA) remains unclear, we characterized the structure of S-CS and explored the relationship between its structure and its effect in alleviating OA.

Methods

Chondroitin sulfate was extracted from sturgeon cartilage by alcohol precipitation. Its structure was thoroughly characterized using infrared spectroscopy, pre-column derivatization, high-performance liquid chromatography with PMP (PMP-HPLC), nuclear magnetic resonance spectroscopy (NMR), and other techniques. A rat OA model was established to explore the mechanism underlying its alleviation of OA. In addition, 16S rRNA sequencing was performed to investigate the role of gut microbiota.

Results

S-CS was identified as a sulfated polysaccharide with an average molecular weight of 68.81 kDa and a GlcUA-to-GalN molar ratio of approximately 1:1. NMR analysis confirmed its characteristic 6-/4-sulfation patterns. Oral administration of S-CS at 100 mg/kg/d significantly alleviated joint damage by inhibiting the NF-κB and p38 MAPK signaling pathways. Specifically, S-CS decreased the levels of p65 and p38 by 18.94% and 52.40% (p < 0.05), respectively, and decreased TNF-α concentration. Moreover, 16S rRNA sequencing showed that S-CS enhanced the diversity and richness of gut microbiota and reconstructed the microbial community structure.

Conclusions

S-CS may be an effective supplement for OA.