Gorodeski G I
Department of Reproductive Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA.
Am J Physiol. 1998 Sep;275(3):C888-99. doi: 10.1152/ajpcell.1998.275.3.C888.
Estrogens increase secretion of cervical mucus in females. The objective of this research was to study the mechanisms of estrogen action. The experimental models were human CaSki (endocervical) and hECE (ectocervical) epithelial cells cultured on filters. Incubation in steroid-free medium increased transepithelial electrical resistance (RTE) and decreased epithelial permeability to the cell-impermeant acid pyranine. Estrogen treatment reversed the effects, indicating estrogen decreases epithelial paracellular resistance. The estrogen effect was time and dose related (EC50 approximately 1 nM) and specific (estradiol = diethylstilbestrol > estrone, estriol; no effect by progesterone, testosterone, or cortisol) and was blocked by progesterone, tamoxifen, and ICI-182780 (an estrogen receptor antagonist). Estrogen treatment did not modulate dilution potential or changes in RTE in response to diC8 or to low extracellular Ca2+ (modulators of tight junctional resistance). In contrast, estrogen augmented decreases in RTE in response to hydrostatic and hypertonic gradients [modulators of resistance of lateral intercellular space (RLIS)], suggesting estrogen decreases RLIS. Estrogen decreased cervical cell size, shortened response time relative to changes in cell size after hypertonic challenge, and augmented the decrease in cell size in response to hypertonic and hydrostatic gradients. Lowering luminal NaCl had no significant effect on RTE, and the Cl- channel blocker diphenylamine-2-carboxylate attenuated the hypertonicity-induced decrease in cell size to the same degree in control and estrogen-treated cells, suggesting estrogen effects on permeability and cell size are not mediated by modulating Na+ or Cl- transport. In contrast, estrogen increased cellular G-actin levels, suggesting estrogens shift actin steady-state toward G-actin and the cervical cell cytoskeleton toward a more flexible structure. We suggest that the mechanism by which estrogens decrease RLIS and increase permeability is by fragmenting the cytoskeleton and facilitating deformability and decreases in cervical cell size.
雌激素可增加女性宫颈黏液的分泌。本研究的目的是探究雌激素的作用机制。实验模型为培养在滤膜上的人CaSki（宫颈内膜）和hECE（宫颈外膜）上皮细胞。在无类固醇培养基中孵育可增加跨上皮电阻（RTE），并降低上皮对细胞不可渗透的酸性吡喃染料的通透性。雌激素处理可逆转这些效应，表明雌激素会降低上皮细胞旁电阻。雌激素的作用具有时间和剂量依赖性（半数有效浓度约为1 nM）且具有特异性（雌二醇=己烯雌酚>雌酮、雌三醇；孕酮、睾酮或皮质醇无作用），并被孕酮、他莫昔芬和ICI-182780（一种雌激素受体拮抗剂）阻断。雌激素处理并未调节对二辛酯或低细胞外Ca2+（紧密连接电阻调节剂）的稀释电位或RTE变化。相反，雌激素增强了对静水压力和高渗梯度[细胞间侧向间隙电阻（RLIS）调节剂]的RTE降低，表明雌激素会降低RLIS。雌激素可减小宫颈细胞大小，相对于高渗刺激后细胞大小的变化缩短反应时间，并增强对高渗和静水压力梯度的细胞大小减小。降低管腔NaCl对RTE无显著影响，且Cl-通道阻滞剂二苯胺-2-羧酸盐在对照细胞和雌激素处理细胞中同等程度地减弱了高渗诱导的细胞大小减小，表明雌激素对通透性和细胞大小的影响不是通过调节Na+或Cl-转运介导的。相反，雌激素增加了细胞G-肌动蛋白水平，表明雌激素使肌动蛋白稳态向G-肌动蛋白转变，并使宫颈细胞骨架向更灵活的结构转变。我们认为，雌激素降低RLIS并增加通透性的机制是通过破坏细胞骨架并促进变形能力以及减小宫颈细胞大小。
