A method for long duration anaesthesia for a new hindlimb ischaemia-reperfusion model in mice.

To study the relationship between ischaemia-reperfusion and multiple organ dysfunction syndrome (MODS), a new anaesthesia method was required to be applied to C57BL/6 mice. These mice are also used in a well accepted, standardized model for MODS using intraperitoneally administered zymosan (zymosan induced general inflammation, ZIGI). The aim was to develop a new model for ischaemia-reperfusion with 6 h of anaesthesia. This and further specific requirements for the combination of ischaemia-reperfusion and the ZIGI method, made us select inhalational anaesthesia using isoflurane in oxygen. This study evaluates whether long-term anaesthesia confounds the results of ischaemia-reperfusion and the ZIGI model. In addition the benefits of using the analgesic buprenorphine were evaluated. Ischaemia was induced with a tourniquet around the hindlimb. Ischaemia and reperfusion were verified by imaging a radioactive tracer with a gamma-camera. It was established that anaesthesia with isoflurane in oxygen caused little perturbation of body temperature and respiratory rate. A survival rate of 89% without noteworthy influence on organs was obtained. Buprenorphine proved to provide adequate analgesia and had no influence on measured parameters. In our experimental setting, this model with long duration anaesthesia allowed us to induce ischaemia and reperfusion of the hindlimb without perturbation of measurements. It also allowed good exposure of the abdomen and facilitated combination with the ZIGI model.