Effect of C-type natriuretic peptide (CNP) and dynamic compression on natriuretic peptide receptors (Nprs) and CNP levels. Npr2 (A), Npr3 (B) CNP (C) and CNP concentration (D), aggrecan (E) and type II collagen gene expression (F). Constructs were cultured in the presence and absence of 0 or 10 ng/ml IL-1β and/or 100 nM CNP or 0.5 μM P19 or 1 μM cANF4-23 6 hours. Error bars represent the mean and standard error of the mean (SEM) values of eight to thirteen replicates from four separate experiments. Asterisks indicate significant comparisons in unstrained (black bars) and strained (white bars) constructs for the multiple treatment conditions. All other comparisons (not indicated) were not significant. For CNP concentration, numbers in brackets indicates the percentage change from unstrained control values.