PC plays a role in inflammation and neutrophil migration after tail transection. (A) Tail transection injury distal to the notochord and vasculature was performed to induce injury-triggered inflammation at 3 dpf. (B) qPCR of total cDNA before and after transection revealed upregulation of il1b mRNA in both wild-type and proc^−/− mutants but was more pronounced for the latter; n = 6 in each group. ∗P < .001 by t test (C) DAF-FM diacetate staining revealed that nitric oxide accumulation after injury was absent in proc^−/− fish. Scale bar, 500 μm. All studies were performed by an observer blinded to genotype and treatment. (D) Fluorescence quantification using CTCF demonstrated a significant decrease of nitric oxide in injured proc^−/− compared to injured wild-type (t test P < .05, n = 7-8 for each group). (E) Sudan Black staining revealed neutrophils in caudal hematopoietic tissue (CHT), boxed area (i), as well as at the tail transection site, boxed areas (ii-iii). Representative images demonstrate less neutrophils at the tail transection site in proc^−/− in panel Eiii in comparison with wild-type siblings in panel Eii. Scale bar, 100 μm. (F) The unchanged neutrophil CHT counts reveal that proc mutation does not affect the production of neutrophils prior to injury (P = .09). Significant reduction of neutrophil numbers in CHT were observed 1 hour after tail transection in wild-type and heterozygous larvae, suggesting neutrophil migration in response to injury. No such change was detected in the proc homozygous group. (G) The absence of PC results in a reduction in neutrophil recruitment. (H) Loss of PS does not affect neutrophil recruitment. (I) Prothrombin (f2) deficiency does not affect neutrophil migration upon tail transection. P values were calculated by unpaired t test. All studies were performed by an observer blinded to genotype and treatment. DAF-FM, diaminofluorescein-FM; CTCF, corrected total cell fluorescence; hpi, hour post injury; ns, not significant.