In brief, 50 ulwell of sample and 50 ulwell of diluted anti C1 2C antibody were preincubated in a polypropy lene mixing plate for 30 minutes at room temperature. Eighty microliters per well of the mixture was transferred to another ELISA plate. After incubation for 1 hour and washing, 100 ulwell of goat anti rabbit horseradish peroxidase conjugate was added and incubated for 30 minutes. After repeated washing, the plate was incubated for 30 minutes and then treated with tetramethylbenzidine for another 30 minutes. The reaction was stopped by using 100 ulwell of 0. 2 M sul furic acid, and absorbance was measured at 450 nm. Statistical analysis Total NO, MMPs, TIMP 1, and C1 2C levels in the conditioned media were measured in duplicate. Quanti tative real time RT PCR was performed in triplicate.
To compensate for interindividual variations, adipokine induced NO and MMPsTIMP 1 levels are presented as ratios versus nonstimulated levels. Continuous values are presented pop over here as meanSEM. Statistical significance was determined with the Mann Whitney U test or Wil coxon matched pairs signed rank test using SPSS for Windows version 11. 0, and P values of 0. 05 were considered significant. Results Adiponectin receptors expression in OA cartilage Immunohistochemical study demonstrated that all OA cartilage samples expressed both AdipoR1 and AdipoR2. AdipoR2 was expressed through all layers, whereas Adi poR1 was expressed mainly in the superficial layer of OA cartilage. Both AdipoR1 and AdipoR2 were significantly more expressed in the lesional cartilage area than in the nonlesional area.
When the expression levels of AdipoR1 and AdipoR2 were compared, the AdipoR2 was more strongly stained than AdipoR1 in both nonlesional and lesional area. Addition ally, the percentage of AdipoR2 positive chondrocytes was significantly higher than that of AdipoR1 positive chondrocytes in both nonlesional and lesional areas. However, the counts order inhibitor of AdipoR1 stained chondrocytes were increased at a higher rate than those of AdipoR2 stained chondrocytes. The percentages of AdipoR1 or AdipoR2 positive chondrocytes were not shown to be correlated with either age or BMI. Effects of adipokines on total NO production and iNOS expression Adiponectin stimulated OA chondrocytes significantly increased total NO produc tion in a dose dependent manner. Adiponectin was also found to upregulate iNOS levels.
Furthermore, adiponectin induced NO production was significantly inhibited by NOS inhibitors, L NMMA and L NIL. Effects of adipokines on MMP 1, MMP 3, MMP 13 and TIMP 1 secretion Adiponectin increased the concentrations of MMP 1, MMP 3, and MMP 13 in the supernatants in a dose dependent manner. However, TIMP 1 levels were not changed. Con sistent with ELISA results, quantitative RT PCR showed that MMP 1, 3, and 13 mRNA levels were upregulated by 30 ugml of adiponectin.