Signals were developed by using an enhanced chemiluminescence system. Immunohistochemistry of SOCS1 in OA and normal cartilage The cartilage samples were fi ed in 4% buffered selleck bio parafor maldehyde for 2 days and then decalcified with buffered EDTA. After dehydration and em bedding in paraffin, sections were cut to a thickness of 4 um, deparaffinized, and rehydrated. Tissue sections from each patient were stained with rabbit antibodies against SOCS1. The subsequent steps were performed automatically at 37 C by using Benchmark T Slide Staining System Specifications. After antigen retrieval and endogenous pero idase blocking, the sections were in cubated with anti SOCS1 at a dilution of 1 100 for 60 minutes at room temperature. To visualize the im munostaining, Ultravision LP kit was used.

The slides were stained by using a di aminobenzidine detection kit and counterstained with hemato ylin. Specimens were evaluated under light microscopy by a pathologist. Percentages of SOCS1 positive chondrocytes were scored in the cartilage area of mild and severe damage, according to the histopathology grade system of OsteoArthritis Research Society Inter national. The number of total cells was counted in at least three randomly selected high power fields. The negative controls were treated by using the same method without the primary antibody. Statistical analysis All e periments were independently repeated at least 3 times, and data were e pressed as mean SEM. For comparison of continuous variables, the Mann Whitney test, Kruskal Wallis test, or Wilco on signed rank test was used as appropriate.

For multiple comparisons, Bonferroni correction was applied. Statistical Batimastat analyses were performed by using PASW Statistics version 18 software and P or cor rected P 0. 05 was considered significant. Results Increased SOCS1 e pression in OA cartilage IHC staining showed that SOCS1 positive chondrocytes were observed mainly in the superficial layers of OA car tilage and that SOCS1 was present in the cytoplasm and or nucleus of chondrocytes, consistent with previous studies. The e pression of SOCS1 was significantly increased in OA cartilage compared with healthy cartilage. In healthy cartilages of the femoral head, 1. 4 0. 5% of chondrocytes e pressed SOCS1 as compared with 26. 4% 6. 1% in mild and 70. 0 6. 7% in severe OA cartilage lesions. IL 1B induced SOCS1 e pression in primary HACs Ne t, we e amined whether IL 1B could induce SOCS1 e pression in HACs. At baseline, the isolated chondrocytes e pressed SOCS1 mRNA at a lower level. After stimulation with IL 1B for 4 hours, the SOCS1 mRNA level increased significantly in a dose dependent manner. Accordingly, SOCS1 protein e pression was increased after IL 1B stimulation.