Neutrophil regulation of splanchnic blood flow after hemorrhagic shock.

OBJECTIVE: This study examines the hypothesis that neutrophils impair splanchnic blood flow during resuscitation from hemorrhage by inhibiting the release of the compensatory vasodilator PGI2 from the bowel. SUMMARY BACKGROUND DATA: Resuscitation from hemorrhagic shock is associated with neutrophil infiltration into the intestine, reduced splanchnic perfusion, and reduced release of PGI2 from the intestine. METHODS: Sprague-Dawley rats received either vinblastine (VIN) to deplete circulating neutrophils or normal saline (NS). These animals then underwent either hemorrhage and resuscitation (SK + R) or sham operation (SHAM). Superior mesenteric artery flow and splanchnic 6-keto PGF1a (metabolite of PGI2) release were measured. RESULTS: Superior mesenteric artery blood flow was significantly greater in VIN-treated animals sustaining SK + R than in those treated with NS (p < 0.05). Neutrophil depletion preserved 6-keto PGF1a release after SK + R, whereas 6-keto PGF1a release in the NS-treated, SK + R group was significantly reduced (p < 0.05). CONCLUSION: These data are compatible with the hypothesis that neutrophils may influence splanchnic perfusion after SK + R by inhibiting splanchnic PGI2 release.