Efficacy of Bletilla striata polysaccharide on hydrogen peroxide-induced apoptosis of osteoarthritic chondrocytes

Osteoarthritis (OA) is a degenerative joint disease affecting millions of peoples worldwide. Though the etiology of OA includes joint injury, obesity, aging, and heredity, oxidative stress is majorly considered as the hallmark of OA initiation and clinical progression. Traditional pharmacologic therapies such as acetaminophen, non-steroidal anti-inflammatory drugs, and opioids are effective only against relieving pain and not capable of reverting damaged cartilage. Bletilla striata is a chinese herb majorly reported for its wound healing and anti-inflammatory property. The objective of this study is to demonstrate the potential of Bletilla striata polysaccharide (BSP) as a biomaterial for oxidative stress induced cartilage tissue repair. The polysaccharide extracted and purified from B. striata was characterized by Fourier-Transform Infrared (FT-IR) Spectrometer and H-1, C-13 Nuclear Magnetic Resonance (NMR) Spectrometer. Rheological measurements of BSP hydrogel were performed using a rheometer under the frequency sweep model. The BSP also showed antioxidant effects by ABTS antioxidant activity assay. The biocompatibility and cytotoxicity of BSP was demonstrated by WST-1 and LDH assay. H2O2 induced oxidative stress was selected to generate osteoarthritic chondrocytes and its detrimental effect was demonstrated by live/dead staining. Finally, the quantitative gene expression of ECM-related genes was studied by RT-PCR in BSP treated and non-treated groups. The outcome of this study has revealed that the down-regulation of catabolic gene expression by BSP treatment may open-up the development of new therapeutic approaches in OA.