ABSTRACT
BACKGROUND: Immune function after hemorrhagic shock and subsequent sepsis is characterized by an early proinflammatory burst of IL-6, and high IL-6 levels have been linked to high mortality after trauma and in sepsis. Trans-signaling is defined as the activation of cells that do not express the membrane bound IL-6 receptor by the complex of IL-6 and the soluble IL-6 receptor (sIL-6R). Gp130-Fc is able to bind the IL-6/sIL-6R complex, and beneficial effects of IL-6 blockade in chronic inflammatory diseases have been shown. The first aim of this study was to investigate the potential effect of a gp130 blockade via the gp130-Fc antibody causing impairment of IL-6 signaling. The second aim was to find out what role the IL-6/sIL-6R complex can play in the context of hemorrhagic shock and subsequent sepsis as an acute inflammatory disease. MATERIAL AND METHODS: Male CBA/J mice were subjected to hemorrhagic shock (35+/-5 mmHg for 90min and fluid resuscitation) or sham operation. At resuscitation each animal received either 0.5mg gp130-Fc or placebo (PL) i.p. At 48 h after resuscitation, both splenocytes and peritoneal macrophages (pMphi) were harvested or polymicrobial sepsis was induced by cecal ligation and puncture. Survival over 10 d was determined. Release of IL-6, TNF-alpha, and IL-10 of pMphi and release of IL-2, IL-10, and IFN-gamma of splenocytes was assessed by ELISA. Proliferation of splenocytes and their morphologic damage were determined. RESULTS: Binding of the IL-6/sIL-6R complex by gp130-Fc led to significant lower IL-6 levels compared with placebo treated animals. Placebo treated males showed depressed proinflammatory immune response (IL-2, IL-6) after hemorrhagic shock. While splenocyte proliferation was significantly reduced directly after hemorrhagic shock and restored after 48 h by gp130-Fc, pMphi cytokine release was not influenced. Finally, survival appeared to be unaffected. CONCLUSION: Transsignaling does not seem to play a pivotal role in the development of the immune dysfunction and mortality in our model of hemorrhage and subsequent sepsis.
Subject(s)
Antibodies/pharmacology , Cytokine Receptor gp130/immunology , Interleukin-6/antagonists & inhibitors , Receptors, Interleukin-6/antagonists & inhibitors , Sepsis/metabolism , Shock, Hemorrhagic/metabolism , Signal Transduction/drug effects , Animals , Cell Proliferation/drug effects , Cells, Cultured , Cytokine Receptor gp130/antagonists & inhibitors , Cytokine Receptor gp130/metabolism , Disease Models, Animal , Ileum/pathology , Immune System/drug effects , Immune System/physiology , Interleukin-6/metabolism , Kidney/pathology , Liver/pathology , Lung/pathology , Macrophages, Peritoneal/metabolism , Male , Mice , Mice, Inbred CBA , Monokines/metabolism , Receptors, Interleukin-6/metabolism , Sepsis/immunology , Sepsis/pathology , Shock, Hemorrhagic/immunology , Shock, Hemorrhagic/pathology , Signal Transduction/physiology , Spleen/drug effects , Spleen/metabolism , Spleen/pathologyABSTRACT
Immune function after hemorrhagic shock (shock) and subsequent sepsis is proofed to be sex- and age-related, showing an enhanced immune function and better survival of young females and a deteriorating immune response in advanced age. However, it remains unclear if the observed sex- and age-related effects observed on the immune function mirror the histomorphological changes of the affected organs. To scrutinize a possible association, male and female CBA/J mice (young, 2-3 months; aged 18-19 months) were subjected to shock (35 + 5 mmHg for 90 min and fluid resuscitation) or sham operation. At 48 h after shock, histological specimen at definite sites were harvested (lung, small bowel, liver, and kidney) and immediately stored in 10% formalin. After paraffin embedding, hematoxylin-eosin stain and immunohistochemical stains (vascular cell adhesion molecule 1 [VCAM-1], cluster of differentiation 44 [CD44], signal transducers and activators of transcription 3 [STAT-3]) were performed. In both sexes, aged animals developed significantly increased (P < 0.05) tissue damage in all analyzed organs compared with young mice. Sex differences were noticed in the lungs of young mice, showing a significantly (P < 0.05) lower organ damage score in female animals. Sex-related differences were found for VCAM-1 and cluster of differentiation 44 expression, whereas age-related changes were observed for STAT-3. These results demonstrate that the severity of tissue damage caused by hemorrhagic shock is influenced by sex- and age-related effects. Variances in the VCAM-1 and STAT-3 expression suggest that improved immune function in female and young subjects may be responsible for less shock-induced tissue damage.
