雌二醇对幼兔未成熟心肌缺血-再灌注损伤的保护作用

目的　探讨雌二醇对幼兔心肌缺血一再灌注损伤的保护作用。方法　采用离体心脏Langendorff灌注模型。根据停搏液的不同 ,将 32只 3～ 4周龄雌性日本大耳白兔随机分为 4组 (n =8) :①对照组 (C组 ) ,单用StThomasII停搏液 ;②雌二醇组 (E2 组 ) ,StThomasII停搏液中加入 10 -6mol/L 17 β雌二醇 ;③雌二醇受体阻断剂组 (B组 ) ,StThomasII停搏液中加入 10 -6mol/L 17 β 雌二醇受体阻断剂 4 Hydroxy Tamoxifen ;④EB组 ,StThomasII停搏液中加入 10 -6mol/L 17 β 雌二醇和 4 Hydroxy Tamoxifen。心脏停跳 6 0min ,复灌后的不同时间点观察每组心功能各项指标的恢复率、心肌酶等生化指标及心肌超微结构的改变。结果　E2 组冠脉流出量的恢复率从复灌后 6 0min起、左室发展压和左室压最大变化速率的恢复率从复灌后 4 0min起均高于其他 3组 (P <0 .0 1或 0 .0 5 ) ,心肌超微结构改变则较其他 3组轻 ,心肌含水量、MDA含量及冠脉流出液心肌酶含量均低于其他 3组(P <0 .0 5 ) ,E2 组心肌组织ATP含量高于C组和B组 (P <0 .0 5 )。结论　雌二醇对幼兔缺血一再灌注损伤心肌有较好的保护作用 ,其保护作用为心肌细胞雌二醇受体介导。

Protective Effect of Estradiol on Immature Myocardium of Rabbits with Ischemia-Reperfusion Injury

Objective To study the protective effect of estradiol on immature myocardium of rabbits with ischemia reperfusion injury. Methods The isolated perfused heart model was developed in thirty two 3 to 4 week old female Japanese rabbits. The rabbits were randomly assigned into four groups according to the perfusion solutions for cardiac arrest (n=8): the control group, estradiol group, blocker group and estradiol+blocker group. In the control group, only St Thomasll solution was used; 10 -6 mol/L of 17 β estradiol was added in the St ThomasII solution in the estradiol group; the blocker group was perfused the St Thomasll solution containing 10 -6 mol/L of 4 Hydroxy Tamoxifen (the blocker of estradiol); and the last group, both 10 -6 mol/L of estradiol and 4 Hydroxy Tamoxifen were added in St Thomas II solution. Sixty minutes after cardiac arrested, reperfusion began. The coronary flow (CF), left ventricular developed pressure (LVDP), ±dp/dt max , mycocardial water content, adenosine triphosphate (ATP) and malondialdehyde (MDA) contents of myocardium, creatine phosphokinase (CK) and lactic dehydrogenase (LDH) and glutamic oxalacetic transaminase (GOT) leakage of coronary effluent and the pathologic changes of ultrastructure of myocardium in the four groups were measured at 10, 20, 40, 60 and 90 min after reperfusion. Results The recovery rate of CF and the recovery rate of LVDP and ±dp/dt max in the estradiol group from 60 min and 40 min respectively after reperfusion were higher than those of the other three groups (P< 0.01 or 0.05 ). The contents of water, MDA, and CK, LDH, GOT leakage of coronary effluent in myocardium of the estradiol group were lower compared with those of the other three groups. The ATP content of myocardium in the estradiol group was higher than that of the control group and blocker group. The ultrastructural pathologic changes of myocardium in the estradiol group were slightest in the four groups. Conclusions Estradiol has the protective effect on the immature myocardium of rabbits and the mediator is the estrogen receptor.