Biochemical analysis of CTX II levels as an indicator of cartilage turnover. Quantitative biochemical analysis of cartilage breakdown (type II collagen fragments) was performed on urine samples using the CTX II Pre-Clinical CartiLaps® enzyme-linked immunosorbent assay. Ten animals underwent sham surgery (control) and 10 underwent OA surgery. Five animals from each group were randomly selected for FM studies, and the remaining five for NM studies. Spot urine was collected presurgically and at 2, 4, 8, 12, and 16 weeks after surgery. Samples were assayed for CTX II concentration and normalized to urine creatinine concentration. Mean CTX II concentrations corrected to creatinine ± standard error are shown. Statistical analysis was performed to test for significant differences between groups, at each time point. Only significantly different means are indicated by 'a' and 'b' (P < 0.05; n = 5). FM, forced mobilization; NM, nonmobilized; OA, osteoarthritis.
Appleton et al. Arthritis Research & Therapy 2007 9:R13 doi:10.1186/ar2120