探讨围生期脑缺血再灌注损伤后，不同发育期胎鼠胚脑Wnt信号通路关键分子糖原合成酶激酶(GSK)-3β及β-连环蛋白(catenin) mRNA表达水平变化。

采用完全随机设计，将40只成功受孕的雌性SD大鼠分为实验组及对照组，每组各20只。两组分别于孕14，16，18及20 d(分别计为E14，16，18及20)时，各取5只孕鼠予相关处理：实验组钳夹双侧子宫动脉30 min，建立围生期脑缺血再灌注模型，并于再灌注24 h后留取胎鼠胚脑标本；对照组则不钳夹子宫动脉，仅在与实验组对应时间点留取胎鼠胚脑标本。采用实时定量(RT)-PCR检测胎鼠胚脑Wnt信号通路关键分子GSK-3β和β-catenin mRNA表达水平；采用尼氏染色和TUNEL标记法，检测两组胎鼠胚脑神经细胞凋亡情况。统计学比较两组胎鼠在相同发育期及同组胎鼠在不同发育期胚脑GSK-3β及β-catenin mRNA相对表达量，以及胚脑神经细胞凋亡率差异。

①两组胎鼠在相同发育期(E14，16，18或20)胚脑GSK-3β及β-catenin mRNA相对表达量比较，以及同组胎鼠胚脑GSK-3β或β-catenin mRNA相对表达量在不同发育期(E14，16，18及20)比较，差异均无统计学意义(P>0.05)。②实验组胎鼠胚脑神经细胞凋亡率，在相同发育期均较对照组高，且差异有统计学意义[(0.254±0.001) vs (0.027±0.004)，t＝46.547；(0.256±0.022) vs (0.029±0.003)，t＝45.917；(0.263±0.011) vs (0.029±0.002)，t＝34.355；(0.265±0.031) vs (0.030±0.003)，t＝91.108；均为P<0.001]。不同发育期(E14，16，18及20)同组胎鼠胚脑神经细胞凋亡率比较，差异均无统计学意义(P>0.05)。③胎鼠胚脑尼氏染色结果显示，实验组神经细胞的细胞质嗜碱性增强，细胞核固缩浓染。

Wnt信号通路和发育期宫内缺血缺氧性脑损伤的关系尚待进一步研究。

To study the expression level changes of glycogen synthase kinase(GSK)-3β and β-catenin mRNA of Wnt signaling pathway in embryo brain at different developmental stages after intrauterine hypoxia-ischemia brain damage and reperfusion.

A total of 40 cases of pregnant SD rats were divided into experimental group and control group through completely random design, and each group contains 20 cases. In different gestational stages, such as 14 days(E14), 16 days(E16), 18 days(E18) and 20 days(E20), 5 cases of pregnant SD rats were taken out and deal with follows: for experimental group, the gestational rat's bilateral uterine arteries were occluded for 30 min to establish transient intrauterine ischemia model, then followed by reperfusion, and embryo brain samples were collected at 24 h after reperfusion.For control group, pregnant SD rats were subjected to same surgical procedures without occlusion, and collected embryo brain samples at same time point with experimental group.Real-time polymerase chain reaction(RT-PCR) was used to detect the expression levels of GSK-3β and β-Catenin mRNA of Wnt signaling pathway in embryo brain. The apoptosis of fetal brain cells in two groups of rats were detected by methods of TUNEL and Nissle staining.Differences of the expression levels of GSK-3β, β-Catenin mRNA and the apoptosis rates in embryo brain were compared statistically between two groups of fetal rats during the same developmental stage and in the same group of fetal rats during different developmental stages.

① There were no significant differences between two groups of fetal rats which at same development stages(E14 , 16 , 18 or 20) and among fetal rats at same group but in different development stages(E14, 16, 18 and 20) in expression levels of GSK-3β and β-catenin mRNA in embryo brain(P>0.05). ②The apoptosis rates of embryonic brain nerve cells in experimental group were higher than those of control group at the same developmental stages, (0.254±0.001) vs (0.027±0.004), t=46.547; (0.256±0.022) vs (0.029±0.003), t=45.917; (0.263±0.011) vs (0.029±0.002), t=34.355; (0.265±0.031) vs (0.030±0.003), t=91.108; P<0.001, respectively. There were no significant differences of apoptosis rates of embryonic brain nerve cells in different developmental stages(E14, 16, 18 and 20) in the same groups (P>0.05). ③The results of Nissle staining of embryo brain showed that the cytoplasm of neurons in the experimental group was basophilic increased, and nuclear condensation.

The relationship between Wnt signaling pathway and intrauterine hypoxia-ischemia brain damage in the development stages need further study.