Models of hemorrhagic shock: Differences in the physiological and inflammatory response

► Comparison of standardized hemorrhagic shock models. ► Continuous measurements of physiologic parameters (e.g. mean arterial pressure). ► Comparison of cytokine expression and systemic inflammation after sterile stimulus. ► Recommendations for further studies using hemorrhagic shock models. The hemorrhagic shock (HS) model is commonly used to initiate a systemic post-traumatic inflammatory response. Numerous experimental protocols exist and it is unclear how differences in these models affect the immune response making it difficult to compare results between studies. The aim of this study was to compare the inflammatory response of different established protocols for volume-controlled shock in a murine model. Male C57/BL6 mice 6–10weeks and weighing 20–25g were subjected to volume-controlled or pressure-controlled hemorrhagic shock. In the volume-controlled group 300μl, 500μl, or 700μl blood was collected over 15min and mean arterial pressure was continuously monitored during the period of shock. In the pressure-controlled hemorrhagic shock group, blood volume was depleted with a goal mean arterial pressure of 35mmHg for 90min. Following hemorrhage, mice from all groups were resuscitated with the extracted blood and an equal volume of lactated ringer solution. Six hours from the initiation of hemorrhagic shock, serum IL-6, KC, MCP-1 and MPO activity within the lung and liver tissue were assessed. In the volume-controlled group, the mice were able to compensate the initial blood loss within 30min. Approximately 800μl of blood volume was removed to achieve a MAP of 35mmHg (p