Inhibition of matrix metalloproteinase (MMP) activity prevents relaxin-mediated loss of glycosaminoglycans (GAGs). Conditioned medium from disc hemisections incubated with β-estradiol (Es), relaxin (R), or β-estradiol plus relaxin (Es+R) in the presence of the MMP inhibitor GM6001 or its control analog was assayed by casein substrate zymograms (a, b). Disc digests from these experiments were assayed for GAGs with the 1,9-dimethylmethylene blue assay, and the results were standardized to tissue dry weight (mg). Fold changes in GAG concentration (mean ± SD) were calculated and plotted (c, d). The untreated control (Ct) discs used in all experiments were exposed to control analog only. * P < 0.05, ** P < 0.01, *** P < 0.001 by Fisher's test.
Naqvi et al. Arthritis Res Ther 2005 7:R1-R11 doi:10.1186/ar1451