This study was carried out to investigate the protective effect of prednisolone in rabbit primary cultured articular chondrocytes treated with sodium nitroprusside (SNP), a nitric oxide donor. After a cell phenotype was determined, the MTT assay and Western blot analysis of type II collagen, cylooxygenase-2 (COX-2) and phosphorylated extracellular regulated kinase (pERK) were performed in the control, SNP (298 μg/ml) alone or SNP plus prednisolone (0.05-50 μg/ml)-treated rabbit articular chondrocytes. Immunofluorescence staining of type II collagen was also performed. Cell morphology indicated that SNP treatment induced cytotoxicity, and that the SNP-induced cytotoxicity was inhibited by prednisolone treatment. MTT assay showed that the SNP treatment resulted in a significant decrease in the level of cell viability compared with that of control (p<0.01), and that the prednisolone treatment resulted in a decrease in the SNP-induced cytotoxicity. SNP treatment resulted in a decrease in the level of type II collagen, compared with the control chondrocytes. The prednisolone treatment recovered the down-regulated expression of type II collagen induced by SNP, showing a significant level in 5 μg/ml of the prednisolone treatment group compared to the SNP treatment group (p<0.05). A significant increase in COX-2 was significantly induced by the SNP treatment compared to control chondrocytes (p<0.01). The COX-2 expression was decreased by the prednisolone treatment, showing a significant level in 50 μg/ml of the prednisolone treatment group compared to the SNP treatment group (p<0.05). These phenomena was confirmed by immunofluorescence staining. Furthermore, the SNP treatment significantly induced a decrease of pERK expression compared to the control chondrocytes (p<0.01). The prednisolone treatment recovered its expression, showing a significant level in 0.5 μg/ml of the prednisolone treatment group compared to the SNP treatment group (p<0.05). Taken the above results together, prednisolone is considered to inhibit SNP-induced cell death and dedifferentiation, and modulated expression of COX-2 and pERK in rabbit articular chondrocytes.

Osteoarthritis is one of the commonest causes associated with age-related damage of articular cartilage. Non-steroidal anti-inflammatory drugs are commonly used in osteoarthritic patient. However, long term administration of these drugs results gastrointestinal disorders. Though, most studies have demonstrated in the past that bee venom has therapeutic effect on diseases related to inflammation and pains, but its anti-inflammatory properties have not been so far studied on inflamed chondrocytes (LPS induced) invitro. For the purpose, the study was carried out to determine the effect of bee venom on porcine articular chondrocyte cell using microarray. In this study, we found that 2,235 significantly associated gene (1,404 up-regulated genes and 831 down-regulated genes) that were expressed on inflamed and non inflamed chondrocytes during proliferation. Among the 1,404 up-regulated genes and 831 down-regulated genes, known genes were 372 and 237, respectively. On the other hand, bee venom significantly reduced expression of fetuin involved in acute inflammatory reaction. Our results suggest that this study could be useful database in gene expression profiling of chondrocyte cell treated with bee venom.