Ginsenoside-Rb1 prevents bone cartilage destruction through down-regulation of p-Akt, p-P38, and p-P65 signaling in rabbit.

Background: Osteoarthritis (OA) is the most common joint complaint resulting in pain, disability, and loss of quality of life. On the other hand, ginsenoside-Rb1 is a plant product derived from ginseng that possesses immune-regulation and anti-inflammatory activities. However, it has been reported that different rout of administration but hydrogel-based Ginsenoside-Rb1 in an OA rabbit model has not been investigated.

Purpose: The aim of this study was to investigate the potential effects of ginsenoside-Rb1 such as anti-arthritic activity in a rabbit knee OA model via NF- κB, PI3K/Akt, and P38/(MAPK) pathways.

Study Design: In the current study, rabbit osteoarthritis was induced by hollow trephine on the femur trochlea and the hydrogel-based Ginsenoside-Rb1 sheets were inserted on the rabbit knee to assess the anti-arthritis activity of ginsenoside-Rb1 which is sustained release.

Methods: After the hydrogel-based Rb1 sheet insert on the rabbit knee, macroscopic and micro CT was performed for investigation of chondroprotective effect. Matrix metalloproteinases (MMPs) and apoptotic expression were assessed through Immunohistochemistry and RT-PCR assay. In addition, the flow cytometry technique was used for the investigation of intracellular reactive oxygen species (ROS) production and histological changes were examined by HE, safranin O, and Masson trichrome staining method. Furthermore, the NF- κB, PI3K/Akt, and P38/(MAPK) pathways were investigated using Western blot analysis.

Results: Macroscopic and micro CT investigation of hydrogel-Rb1 treatment showed a dose-dependent chondroprotective effect. Immunohistochemistry and RT-PCR revealed that expression of matrix metalloproteinases (MMPs) and apoptotic markers TNF-α, caspase-3, and bax are down-regulated in a dose-dependent fashion following implantation of hydrogel-Rb. Higher levels of intracellular reactive oxygen species (ROS) were observed in the OA group. In histopathological investigation of hydrogel-Rb1 exhibited larger amounts of chondro cells, glycosaminoglycan's, and collagen compared to the defect group. Furthermore, the NF- κB, PI3K/Akt, and P38/(MAPK) pathways were downregulated by hydrogel-Rb1 while the disease model showed upstream. In the meantime, MMP expression level was considerably down-regulated.

Conclusions: Our results indicate the protective effect of ginsenoside-Rb1 against OA pathogenesis through prevention of apoptosis with suppression of ROS production and activation of NF-κB signaling through downregulation of the MAPK and PI3K/Akt signaling pathways.