Sdc-3 deletion reduces neutrophil recruitment in CXCL1-injected joints. Sdc-3 null and wild-type mice were injected intra-articularly with 3 μg per knee joint of recombinant murine CXCL1 or PBS and after 4 hours processed for histology. (A) Haematoxylin and eosin staining reveals neutrophil recruitment in the synovium following CXCL1 administration with PBS injected as control; insets show detail of synovium. Results are shown from a wild-type joint. Scale bar 500 μm (for inserts 50 μm). (B) Decrease in the number of recruited neutrophils in sdc-3−/−mice compared to wild-type animals following CXCL1 administration. Data are means ± SEM, n = 8 mice per treatment. ***P <0.0001 comparing CXCL1-injected joints. (C) Sdc-3 immunolocalises to the blood vessel in synovium of wild-type mice. (D) is the same image as (C) stained for DAPI to show cell nuclei. (E) absent staining for sdc-3 in a blood vessel in sdc-3 −/−synovium. (F) is the same image as (E) stained for DAPI to show cell nuclei. (G) is a negative control of the synovium of wild-type mouse in the absence of sdc-3 antibody and (H) is the same area stained for DAPI to show the presence of blood vessels. Bar =120 μm in C to H. CXCL1, chemokine C-X-C ligand 1; DAPI, 4',6-diamidino-2-phenylindole; PBS, phosphate-buffered saline.