Unfeasible experimental model of normothermic hepatic ischemia and reperfusion in rats using the Pringle maneuver

BACKGROUND: The negative result of a research does not always indicate failure, and when the data do not permit a proper conclusion, or are contrary to the initial project, should not simply be discarded and archived. AIM: To report failure after performing experimental model of liver ischemia and reperfusion normothermic, continuous or intermittent, in small animals aiming at the study of biochemical and histological parameters after postoperative recovery. METHODS: Fifteen Wistar rats were divided into three groups of five animals each; all underwent surgery, the abdomen was sutured after the proposed procedures for each group and the animals were observed for 6 h or until they died, and then were reoperated. In Group 1, control (sham-operated): dissection of the hepatic hilum was performed; in Group 2: clamping of the hepatic hilum for 30 m; in Group 3: clamping of the hepatic hilum for 15 m, reperfusion for 5 m and another 15 m of clamping. Data from Groups 2 and 3 were compared with Student's t test. RESULTS: All animals of Group 1 survived for 6 h. Two animals in Group 2 died before the 6 h needed to validate the experiment; two did not recover from anesthesia and one survived until the end. In Group 3, four animals died before the 6 h established and one of them survived the required time. Only one animal in Group 2 and one in Group 3 survived and were able to accomplish the study. There was no statistical significance when the results of Groups 2 and 3 were compared (p>0.05). CONCLUSION: The death of six animals before the necessary period of observation turned the initial proposal of the experiment unfeasible.研究背景：研究的阴性结果并非均意味着实验失败，当数据无法得出确切结论，或与初始研究假设相悖时，不应简单将其丢弃并归档封存。 研究目的：本研究旨在建立小型动物常温持续性或间歇性肝脏缺血再灌注（liver ischemia and reperfusion）实验模型，用于术后恢复阶段生化与组织学参数的相关研究，并汇报该模型构建过程中出现的失败案例。 研究方法：选取15只Wistar大鼠（Wistar rats），按每组5只分为3组；所有大鼠均接受手术操作，各组按预设方案完成操作后缝合腹腔，随后对大鼠进行6小时观察或直至其死亡，之后对存活大鼠再次实施手术。第1组为假手术（sham-operated）对照组：仅实施肝门（hepatic hilum）区解剖操作；第2组：阻断肝门血流30分钟；第3组：阻断肝门血流15分钟，再灌注5分钟后，再次阻断肝门血流15分钟。采用t检验（Student's t test）对第2组与第3组的数据进行比较分析。 研究结果：第1组所有大鼠均存活至6小时观察结束。第2组中，2只大鼠在达到实验验证所需的6小时观察时长前死亡，2只未从麻醉中苏醒，仅1只存活至观察结束。第3组中，4只大鼠在预设的6小时观察期内死亡，仅1只存活至规定时长。最终仅第2组与第3组各1只大鼠存活并完成全部实验流程。对第2组与第3组的结果进行比较，未发现统计学显著性差异（p>0.05）。 研究结论：共计6只大鼠在必需的观察期内死亡，使得本实验的初始设计方案无法顺利实施。