The purpose of the present study was to evaluate the potential therapeutic action of the deer bone extract on the repair of rabbit chondrocyte treated with interleukin-1β (IL-1β) and cartilage damaged with monosodium-iodoacetate (MIA)-induced osteoarthritic model.
In vitro test was carried out for the effects of deer bone extract on the proliferation and gene expression using primary cultured rabbit chondrocyte. Through MTT assay, we investigated that deer bone extract was non-toxic to rabbit chondrocyte, and prevented the loss of viability caused by IL-1β treatment. The extract up-regulated the expression of collagen type II (COL2) decreased by IL-1β in chondrocytes. IL-1β markedly up-regulated MMP-1, -3, and -13 in primary cultured chondrocytes, and MMP-3, -13 activations were inhibited by co-incubation with deer bone extract in contrast with the control group. These results suggested that the anti-inflammatory effects of deer bone extract could be potential value of the prevention and treatment of OA.
In animal study, we also investigated the effects of deer bone extract on the pro-inflammatory cytokines and gene expressions using MIA-induced OA model. MIA promotes the loss of articular cartilage similar to that noticed in human OA. OA rats were assigned sham control group (SC; n=10), OA control group (NC; n=10) and deer bone extract-treated + OA group (low deer bone extract-treated group: LDB, high deer bone extract-treated group: HDB, n=10). Treated groups were orally administrated extract of deer bone after MIA injection. With respect to the catabolic pathway, we found that deer bone extract is involved in suppression of IL-1β, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The results of quantitative polymerase chain reaction (qPCR) using osteoarthritic cartilage showed that gene expressions of COL2 and tissue inhibitor of metalloprotease (TIMPs) are significantly up-regulated by taking extract of deer bone (p<0.05). We also found that the extracts down-regulated the messenger RNA (mRNA) expression of MMPs. Also, micro-computed tomographic (Micro-CT) analysis showed protective effects of deer bone extract on trabecular bone. The LDB and HDB groups tended to increase in trabecular thickness (Tb.Th) and trabecular bone volume fraction (BV/TV) compared to NC group significantly (p<0.05). There is no difference in trabecular number (Tb.N) between treated groups (LDB, HDB) and NC group. The level of trabecular separation (Tb.Sp) significantly decreased in LDB and HDB groups compared with NC group (p<0.05). These results indicate that extract of deer bone may be a potential therapeutic agent for the protection of articular cartilage against progression of OA through inhibiting inflammatory mediators and MMPs expression as well as up-regulating the mRNA expression of COL2.