Kilarski W M, Fu X, Bäckström T, Roomans G M, Ulmsten U
Department of Cytology and Histology, Jagiellonian University, Kraków, Poland.
Acta Physiol Scand. 1996 Aug;157(4):461-9. doi: 10.1046/j.1365-201X.1996.500247000.x.
Previous studies by electron microscopy and laser confocal microscopy of immunohistochemically stained sections have shown that during pregnancy the extent of gap junction formation in human myometrium is low, but that an increase occurs in the active stages of labour despite a high concentration of progesterone in maternal blood. The present investigation focused on the effect of in vitro exposure of isolated myometrial tissue to progesterone, oestradiol and oxytocin, on the number of gap junction plaques in human myometrium at term. Myometrial biopsies were obtained at term from 13 pregnant women who had an elective caesarean section in the 37th or 40th week of pregnancy. The biopsies were immersed immediately in Hepes buffer and buffer containing 0.5, 5.0 micrograms mL-1 of progesterone, and 0.1 micrograms mL-1 of oestradiol. The muscle biopsies were trimmed under a stereo microscope into strips along the bundles of smooth muscle cells and mounted in tissue baths, superfused with Hepes buffer supplemented with glucose (0.01 mM); subsequently the strips were exposed to buffer containing different concentrations of progesterone, oestradiol and oxytocin. Incubation of the muscle strips for 180 min resulted in a significant decrease of the number of gap junctions (P < 0.01). Neither oestradiol or oxytocin, alone or in combination, had a significant effect on the maintenance of the number of gap junctions. The progesterone concentration of 5.0 micrograms mL-1, combined with oxytocin, and with or without oestradiol has a significantly positive effect on the number of gap junction plaques in strips of human myometrium at term (P < 0.05 vs. buffer alone). The high concentration of progesterone in the superfusion medium during in vitro experiments may be responsible for the maintenance of high numbers of gap junction complexes in term human myometrium. This finding is of interest in the light of findings of persisting high progesterone levels in maternal blood during labour.
先前通过电子显微镜以及对免疫组织化学染色切片进行激光共聚焦显微镜观察的研究表明，在孕期，人子宫肌层中缝隙连接形成的程度较低，但尽管母体血液中孕酮浓度较高，在分娩活跃期缝隙连接的数量仍会增加。本研究聚焦于离体子宫肌层组织在体外暴露于孕酮、雌二醇和催产素后，对足月时人子宫肌层中缝隙连接斑数量的影响。足月时，从13名在妊娠第37周或第40周进行择期剖宫产的孕妇获取子宫肌层活检组织。将活检组织立即浸入赫氏缓冲液以及含有0.5、5.0微克/毫升孕酮和0.1微克/毫升雌二醇的缓冲液中。在体视显微镜下将肌肉活检组织沿平滑肌细胞束修剪成条带，安装在组织浴槽中，用添加了葡萄糖（0.01毫摩尔）的赫氏缓冲液进行灌流；随后将条带暴露于含有不同浓度孕酮、雌二醇和催产素的缓冲液中。肌肉条带孵育180分钟后，缝隙连接数量显著减少（P < 0.01）。单独或联合使用雌二醇或催产素，对缝隙连接数量的维持均无显著影响。5.0微克/毫升的孕酮浓度与催产素联合使用，无论有无雌二醇，对足月时人子宫肌层条带中的缝隙连接斑数量均有显著的正向影响（与单独使用缓冲液相比，P < 0.05）。体外实验期间灌流培养基中高浓度的孕酮可能是足月人子宫肌层中大量缝隙连接复合物得以维持的原因。鉴于分娩期间母体血液中孕酮水平持续较高这一发现，该结果很有意思。
