冬眠动物达乌尔黄鼠离体心脏对缺灌和再灌损伤的耐受性

秋季未入眠之达乌尔黄鼠离体心脏用Langendorff方法灌流，平衡10min，全心缺灌15min，然后再灌10min。于缺灌期和再灌期分别定时收集心脏冠脉流出液，测定流份中肌酸激酶(CK)的活性(U·L^－1)，同时记录心电图和心脏收缩力。此外，用恒温动物大鼠作为冬眠动物黄鼠的实验对照，经受完全相同的实验处理。缺灌15 min期内，两种动物心脏皆有大量CK释放，释放量与缺灌时间呈线性关系。但黄鼠各采样点CK释放值都低于大鼠，提示黄鼠心脏对缺灌损伤的耐受性强于大鼠。再灌期大鼠心脏有两个CK释放峰，而黄鼠仅有第Ⅰ峰，且其活性值(179±32U·L^－1)显著低于大鼠(255±17 U·L^－1，P<0.05)。再灌期黄鼠室颤和室速发生率以及心脏收缩幅度下降百分率皆显著低于大鼠(P<0.01)。上述结果证明，与大鼠相比较，冬眠动物黄鼠心脏对缺灌和再灌损伤具有较强的耐受性。

The Resistance to Ischemia Reperfusion Injury of the Isolated Heart from Hibernator Ground Squirrel ( Citellus dauricus )

Isolated hearts tacken from nonhibernating ground squrrel in Autumn were perfused by Langendorff method with Krebs-Henseleit solution. Hearts were first perfused for 10 min to establish steady state, then stopped for 15 min ischemia (noperfusion), and finally followed by 10 min reperfusion. Coronary effluents were sampled at certain time intervals during noperfusion and reperfusion period. The enzymatic activity of CK(U·L^-1) was analysed from the coronary effluent, in the mean time the ECG and contraction amplitude were measured. Parallel experiments with the same protocal have been performed in nonhibernator animal, rat, for comparasion. During 15 min noperfusion period there was a remarkable CK release from both animal hearts. The amount of CK release was proportional to the noperfusion time course in both hearts, but the extent of CK release form rat heartwas much more bigger than that of ground squirrel. During reperfusion period the CK release of rat heart was biphasic while that of the ground squirrel was monophasic and the peak of the 1st releasing phase of the former (255±17 U·L^-1)was much higher than that of the later (179±32U·L^-1). The incidence of ventricular fibrillation and ventricular tachycadia as well as the percentage of decreasedcontraction amplitude were all significantly reduced in ground squirrel heart in comparation with rat heart. These results indicate that the heart from ground squirrel exhibits a stronger resistence to ischemia reperfusion injury than that from rat, presenting a striking contrast between hibernator and nonhibernator.