Entry of gut lymph into the circulation primes rat neutrophil respiratory burst in hemorrhagic shock.
Ключові слова
Анотація
OBJECTIVE
Endothelial cell injury by polymorphonuclear neutrophil (neutrophil [PMN]) respiratory burst after trauma and hemorrhagic shock (T/HS) predisposes subjects to acute respiratory distress syndrome and multiple organ failure. T/HS mesenteric lymph injures endothelial cell and lymph duct ligation (LDL) before T/HS prevents pulmonary injury. We investigated the role of mesenteric lymph in PMN priming by T/HS.
METHODS
Prospective experiment in rats.
METHODS
University hospital laboratory.
METHODS
Adult male rats.
METHODS
Mesenteric lymph was obtained from rats undergoing T/HS (30 mm Hg, 90 mins) or sham shock (T/SS). Plasma was harvested from uninstrumented control (UC), T/HS, T/SS, and T/HS+LDL rats. PMNs were isolated from UC, T/HS, and T/HS+LDL rats.
RESULTS
PMNs from UC rats were incubated in buffer, 1% T/HS lymph, and 1% T/SS lymph. PMNs from UC rats were incubated in UC, T/HS, T/SS, and T/HS+LDL plasma. PMN respiratory burst was initiated by using macrophage inflammatory protein (MIP)-2/platelet-aggregating factor (PAF) or phorbol myristate acetate. Cytosolic calcium ([Ca2+]i) responses to MIP-2/PAF were assayed in PMN from UC, T/HS, and T/HS+LDL rats. PMN preincubated in T/HS lymph showed significant elevations in MIP/PAF-elicited respiratory burst compared with T/HS lymph or buffer only (p <.05; analysis of variance/Tukey's test). T/HS lymph incubation also increased (p <.05) phorbol myristate acetate elicited respiratory burst compared with buffer or T/SS. Preincubation in T/HS plasma increased MIP-2/PAF-elicited respiratory burst (p <.05) compared with UC or T/SS plasma. LDL blocked T/HS priming of respiratory burst. Control PMN [Ca2+]i responses to MIP-2 and PAF were low. T/SS PMN were significantly more responsive, but the T/HS PMN showed still higher responses (p <.01). LDL reversed the priming of [Ca2+]i responses by T/HS (p <.01).
CONCLUSIONS
PMNs are primed by T/HS lymph but not T/SS lymph and by T/HS plasma but not T/SS plasma. LDL before shock prevents T/HS plasma from priming PMN. The magnitude of respiratory burst found here paralleled the [Ca2+]i responses seen to receptor dependent initiating agonists. Mesenteric lymph is both necessary and sufficient to prime PMN after T/HS in the rat, and it primes PMN in part by enhancing [Ca2+]i responses to G-protein coupled chemoattractants. Mesenteric lymph mediates postshock PMN dysfunction.
