Gender dimorphism in neutrophil priming and activation following trauma-hemorrhagic shock

Although gender influences T-cell, macrophage and organ functions following trauma-hemorrhage and resuscitation (T-H), it remains unknown whether it also influences polymorphonuclear cell (PMN) activity under such conditions. To study this, proestrus female and male Sprague-Dawley rats underwent trauma-hemorrhage followed by fluid resuscitation. Circulating PMNs were assessed for superoxide (O2-) and elastase production and tissues were analyzed for myeloperoxidase (MPO) activity and TBARS (thiobarbituric acid reactive substances) as a marker of oxidative injury, at 2 and 24 h after resuscitation. PMA stimulated O2- production was not influenced by T-H or gender. In contrast, fMLP-stimulated O2- and LPS-stimulated elastase release by PMNs from male T-H rats was greater than that of females. A significant MPO activity and TBARS in tissues of both male and female rats was induced; however, MPO activity and TBARS levels were higher in males following T-H. Levels of the chemokine CINC-1 were elevated in the lungs of male, but not of proestrus females after T-H. Thus, decreased PMN priming and activation in proestrus females, compared to males, occurs following T-H resulting in decreased cellular injury and organ damage that is likely to contribute to improved outcome under those conditions.