Fig. 1. Enhanced CHS in SPARC-knockout mice. SPARC^+/+ and SPARC^–/– mice were sensitized with DNFB on the dorsal side of the right ear on day 0. Five days later, mice were challenged on the left ear. Control mice from the two strains were treated only with the challenge dose of DNFB. Panel A shows ear swelling measurements (mean±s.d.) at 24 and 48 hours after challenge for each group of mice. Mean values were significantly different at both time points (P<0.001). Results are representative of five independent experiments. Panel B shows the inflammatory response in sections of the challenged ear of SPARC^+/+ and SPARC^–/– mice. Tissues were harvested 24 hours after DNFB challenge, fixed in 10% neutral buffered formalin and sections stained with hematoxylin and eosin. Owing to extensive swelling, only a portion of the SPARC^–/– section is shown (cartilage is below the cut line of the figure and was omitted to ensure a magnification matching that of the control panel). Inflammatory infiltrate appears to be more abundant in the SPARC^–/– section.