Western blotting on human OA cartilage extract. A. Lane1 and 8: human OA cartilage extract1; Lane 2 and 9: human OA cartilage extract 2; Lane 3 and 10: human OA cartilage extract3; Lane 4 and 11: GuHCl extraction buffer. Lane 5 and 12: human skeletal muscle extract; Lane 6: muscle extraction buffer. Lane 7: marker. Lane 1–7 was incubated with NB509-11G8, while Lane 8–12 was incubated with non-sense mouse IgG. The same size of 17 kDa band was visualized in three cartilage extract, but not in the muscle extract. No any band was detected in neither cartilage extract nor muscle extract by non-sense mouse IgG. B. Peptide inhibition western blotting on human OA cartilage extracts. Lane 5: marker; Lane 1and 6: human OA cartilage extract1; Lane 2 and 7: human OA cartilage extract2; Lane 3 and 8: human OA cartilage extract3. Lane 4 and 9: GuHCl extraction buffer. The 17 kDa bands in 3 human OA extracts were blocked by selected peptide, but not truncated peptide.