雌激素激活子宫Telocytes中T型钙通道促进子宫蠕动波收缩的作用机制研究

Uterine peristalsis plays an important role in embryo implantation. However, its origin and regulation mechanism remains unclear. Telocytes, the ‘interstitial Cajal-like cells’ out of digestive canal, are located in uterus and its membrane depolarization could spread into neighbouring smooth muscle cells through gap junctions to activate contraction. However, the mechanism of Telocytes regulating uterine contraction is still blank. Here, we put forward a hypothesis that Telocytes are sensors of estrogen level, and they could activate T-type Ca2+ channel through non-genomic signalling events, increase intracellular Ca2+ level, raise membrane potential, finally induce myometrium contraction. Thus, studies are designed to observe influence of estrogen on the current of T-type Ca2+ channel, intracellular Ca2+ concentration and membrane potential changes in uterine telocytes. In conclusion, this study aims at revealing the mechanism of uterine telocytes transforming estrogen signal into uterine contraction, providing a target in inhibiting abnormal uterine peristalsis and improveing embryo transfer outcome.

子宫蠕动波在胚胎着床中起重要作用，但其调控机制不清。一般认为，子宫中存在类似胃肠道Cajal间质细胞的起搏细胞——Telocytes，通过缝隙连接激发子宫平滑肌细胞产生收缩运动，但目前尚不明确Telocyte调控子宫收缩的机制。本课题创新性地提出子宫Telocytes作为雌激素感受器，通过非基因组途径激活T型钙通道，产生膜电位变化，进而调控子宫平滑肌收缩的假说。拟通过比较子宫Telocytes在雌激素、雌激素核受体拮抗剂、T型钙通道特异性阻断剂的作用下，Telocyte中T型Ca2+通道电流、细胞内Ca2+浓度及膜电位变化，揭示人类子宫肌层中Telocytes将雌激素信号转化为平滑肌收缩效应的机制。本研究将子宫Telocytes与子宫蠕动波相联系，对抑制异常子宫蠕动波提供干预靶点和理论依据，以期改善胚胎移植后妊娠结局。

子宫蠕动波在胚胎着床中起重要作用，但其调控机制不清。子宫蠕动与胃肠道蠕动相似，具有自发性、节律性和方向性的共同特征，子宫中存在类似胃肠道Cajal间质细胞的起搏细胞——Telocytes，通过缝隙连接激发子宫平滑肌细胞产生收缩运动，但目前尚不明确Telocyte调控子宫收缩的机制。本课题创新性地提出子宫Telocytes作为雌激素感受器，通过增强T型钙通道的激活，引起Ca2+内流产生膜电位变化，进而调控子宫平滑肌收缩的假说。本研究通过收集人子宫肌层组织用于原代细胞培养，根据Telocytes独特的形态学特征以及表达特异性标记物c-kit和CD34，证实了人类子宫肌层中存在Telocytes细胞。对Telocytes细胞特异性标记物c-kit、CD34和T型钙通道α亚单位Cav3.1(α1G)、Cav3.2(α1H)的双重免疫荧光染色证实Telocyte细胞表达T型钙通道。应用钙离子荧光指示剂Fluo-4 AM标记Telocytes细胞内钙离子，在激光共聚焦显微镜下添加高选择性T型钙通道阻滞剂NNC 55-0396可显著降低细胞内Ca2+荧光强度，但雌二醇可增强荧光强度。最后，应用全细胞膜片钳技术发现在Telocytes细胞中可以激发T型钙电流，而添加NNC 55-0396可阻断T型钙电流。将Telocytes细胞在不同浓度的雌二醇中孵育后检测T型钙电流，T型钙电流峰值随着雌激素浓度的升高而增加，呈剂量依赖性。本研究结果明确了子宫Telocytes作为雌激素感受器，将雌激素信号转化为T型钙离子内流信号，起到了信息中转站的作用，可能作为子宫蠕动波启动的起搏细胞，并最终引起下游平滑肌收缩效应的机制。本研究将子宫Telocytes与子宫蠕动波相联系，对抑制异常子宫蠕动波提供干预靶点和理论依据，以期改善胚胎移植后妊娠结局。