目的:通过建立不同梯度低温停循环的家猪模型，探讨中低温停循环是否能提供与深低温停循环相当的重要脏器保护效果，并为急性主动脉夹层患者术中的低温范围选择提供临床指导。方法:将13只家猪采用随机分配的方法分为3组，中低温停循环组(T＝25℃，n＝5)，深低温停循环组(T＝15℃，n＝5)及空白对照组(n＝3)。对照组不做任何处理，两组实验组建立体外循环并降温，在不同温度下停循环0.5 h，在麻醉后(T1)、鼻咽温降至32℃(T2)、鼻咽温降至25℃/15℃(T3)、停循环0.5 h(T4)、复温至32℃(T5)、复温至36℃(T6)、停机2 h(T7)、停机4 h(T8)、停机6 h(T9)和停机24 h(T10)10个时间点留取血液标本，比较两实验组肝肾功能指标(BUN、Cr、ALT和AST)的异同及变化情况。实验结束后处死家猪，留取脑、肺、肝、肾等组织，使用TUNEL、免疫组化等技术分析家猪组织，观察对照组及实验组凋亡相关蛋白阳性细胞率及凋亡指数的差别。结果:实验结果显示，实验组的各重要脏器凋亡相关蛋白阳性细胞率及凋亡指数的对比差异均无统计学意义(n P>0.05)，肝肾功能的指标在两实验组中也类似，差异均无统计学意义(n P>0.05)。n 结论:中低温停循环与深低温停循环对重要脏器的保护作用无明显差异，这进一步证明了临床中应用中低温停循环的安全性和可靠性。“,”Objective:To examine whether the use of moderate hypothermic circulatory arrest in a pig model provides comparable vital organ protection outcomes to the use of deep hypothermic circulatory arrest.Methods:Thirteen pigs were randomly assigned to 30 minutes of hypothermic circulatory arrest without cerebral perfusion at 15℃(n=5), 25℃(n=5) and a control group(n=3). The changes in standard laboratory tests and capacity for protection against apoptosis in different vital organs were monitored with different temperatures of hypothermic circulatory arrest management in pig model to determine which temperature was optimal for hypothermic circulatory arrest.Results:There were no significant differences in the capacity for protection against apoptosis in vital organs between 2 groups(n P>0.05, respectively). Compared with the moderate hypothermic circulatory arrest group, the deep hypothermic circulatory arrest group had no significant advantages in terms of the biologic parameters of any other organs(n P>0.05).n Conclusion:Compared with deep hypothermic circulatory arrest, moderate hypothermic circulatory arrest is a moderate technique that has similar advantages with regard to the levels of biomarkers of injury and capacity for protection against apoptosis in vital organs.