Basic research for fetal cardiac surgery

背景：建立安全的胎儿心脏搭桥术是实施胎儿心脏外科手术的必要条件。我们研究了与胎儿心脏搭桥相关的脐带血管的细胞凋亡。方法：选用13只妊娠母羊。将胎羊分为体外循环(CB)组(n=7)和对照组(n=6)。CB组使用离心泵维持体外循环30分钟。转流后观察胎儿60min，取脐动脉。对照组为假手术组，取脐动脉。取脐动脉组织标本进行TUNEL染色和免疫印迹法检测细胞色素c、Bax、Bcl2、Bclxl和Caspase3的表达。结果：两组脐动脉TUNEL阳性核数目相似(CB组0.57±0.29，对照组0.33±0.21，P=0.37)。两组间总caspase-3水平差异无统计学意义(CB组1.40±0.43，对照组0.99±0.09，P=0.39)。两组均未检测到裂解的caspase-3。胞浆细胞色素c水平两组间差异无统计学意义(CB组1.99±0.75，对照组2.80±1.41，P=0.60)。两组Bax/Bc1-2比值差异无统计学意义(CB组1.66±0.66，对照组1.49±0.32，P=0.83)。两组间Bclxl水平差异无统计学意义(CB组0.59±0.07，对照组0.58±0.10，p=0.93)。结论：我们已经证明，胎儿脐带没有在脐动脉中触发额外的凋亡信号，这表明胎儿心脏手术后脐血管可能是开放的。

Background : To establish the safe fetal cardiac bypass is mandatory to perform the fetal cardiac surgical interventions. We investigated apoptosis in umbilical vessels related to fetal cardiac bypass. Methods : Thirteen pregnant ewes were used in the present study. Fetal lambs were divided into the cardiac bypass (CB) group (n=7) and the control group (n=6). In the CB group, cardiac bypass was maintained for 30 minutes using a centrifugal pump. After bypass, the fetuses were observed for 60 minutes and then the umbilical artery was harvested. In the control group, sham operation was performed and the umbilical artery was harvested. Umbilical artery tissue samples were used for TUNEL study and western blotting for Cytochrome c,Bax,Bcl-2,Bcl-xL, and Caspase 3. Results : The TUNEL-positive nuclei in umbilical artery were similar in both groups (CB group 0.57±0.29,control group 0.33±0.21 positive nuclei per high-power field, p=0.37). There were no significant differences in total caspase 3 levels between the 2 groups (CB group 1.40±0.43,control group 0.99±0.09,p=0.39). Cleaved caspase 3 were not detected in both groups. There were no significant differences in cytosolic cytochrome c levels between the 2 groups (CB group 1.99±0.75, control group 2.80±1.41,p = 0.60). There were no significant differences in Bax/Bc1-2 ratio between the 2 groups (CB group 1.66±0.66,control group 1.49±0.32,p = 0.83). There were no significant differences in Bcl-xL levels between the 2 groups (CB group 0.59±0.07,control group 0.58±0.10,p=0.93). Conclusions : We have demonstrated that fetal CB have not triggered additional apoptotic signals in the umbilical artery, suggesting that umbilical vessels may be patent after fetal cardiac surgery