Sexual dimorphism in the activation of neutrophils by shock mesenteric lymph.

Background: After trauma/hemorrhagic shock (T/HS), inflammatory products exit the gut via mesenteric lymph. These products can prime neutrophils (PMN) and predispose to lung injury. Female gender and the proestrous state (PE) may confer protection against lung injury after T/HS. We therefore studied the dependence of T/HS-induced PMN priming on gender and stage of estrous. Materials and Methods: T/HS was induced in male (M) and proestrous female (F) rats by laparotomy plus hemorrhagic shock (30 mm Hg, 90 min) followed by reinfusion of shed blood. Six hours later rats were sacrificed and plasma was obtained. Control male rat PMN were primed 5 min in buffer or in the plasma of M-T/HS or F-T/HS rats (n = 4-6/group). PMN were then assayed using DHR for respiratory burst (RB) initiated by sequential MIP-2 and PAF stimulation (MIP/PAF). Because MIP and PAF mobilize cell calcium ([Ca2+]i) in a step crucial for RB initiation, we also assayed PMN [Ca2+]i responses to MIP/PAF. Results: M-T/HS plasma primed PMN RB (...