Bansode F W, Chauhan S C, Makker A, Singh M M
Division of Endocrinology, Central Drug Research Institute, Lucknow, India.
Contraception. 1998 Jul;58(1):61-8. doi: 10.1016/s0010-7824(98)00055-9.
The period of maximal endometrial sensitivity in the rat was characterized by high alkaline phosphatase activity in uterine luminal and glandular epithelium and endometrial stroma. The activity in endometrial stroma increased following decidualization. Pinopod development on the endometrial surface was first observed during the presensitivity period. Their number increased, apparently more so on the antimesometrial rather than the mesometrial segment of the uterus, on the day of maximal sensitivity. Inhibition in endometrial sensitivity by single anti-implantation (1.25 mg/kg, po) dose of centchroman on day 1 post-coitum (p.c.), although it did not affect alkaline phosphatase activity on days 2 and 3 p.c., caused complete inhibition in its activity in uterine luminal and glandular epithelium and pinopod development on days 4 and 5-coinciding, respectively, with time of entry of preimplantation embryos into the uterus and period of maximal endometrial sensitivity in this species. Significant decrease in enzyme activity was also evident in the entire endometrial stroma and myometrium, except blood capillaries, on these days. In comparison, prevention of entry of native embryos into the uterus by placing a ligature at the utero-tubal junction had no effect on pinopod development, but caused marked decrease in enzyme activity in luminal and glandular epithelium only during the immediate postimplantation period. The uterine lumen on the day of maximal sensitivity in centchroman-treated rats appeared highly distended and was lined with tall columnar epithelium, in comparison to low cuboidal epithelium in controls. The findings demonstrate: (a) a correlation between uterine luminal epithelial alkaline phosphatase activity and endometrial sensitivity; (b) complete inhibition in enzyme activity in luminal and glandular epithelium following centchroman treatment might be related to altered permeability characteristics of epithelial cells, which together with the absence of pinopods and highly distended uterine lumen on the day of maximal sensitivity, suggest inhibition of endocytosis/pinocytosis of luminal fluid, luminal closure, apposition of blastocyst trophoblast to luminal epithelium, and secretory activity of glandular epithelium; (c) pinopod development on the endometrial surface was independent of presence of viable blastocysts in utero; and (d) complete absence of pinopods suggests lack of endometrial sensitivity, but their presence might not necessarily indicate a sensitized endometrium in the rat.
大鼠子宫内膜最大敏感性时期的特征是子宫腔和腺上皮以及子宫内膜基质中碱性磷酸酶活性较高。蜕膜化后，子宫内膜基质中的活性增加。在敏感性前期首次观察到子宫内膜表面的微绒毛突起发育。在最大敏感性当天，它们的数量增加，显然在子宫的反系膜段比系膜段增加得更多。在交配后第1天（p.c.）单次给予抗着床剂量（1.25 mg/kg，口服）的炔诺酮抑制子宫内膜敏感性，尽管在交配后第2天和第3天不影响碱性磷酸酶活性，但在第4天和第5天导致子宫腔和腺上皮中的酶活性完全抑制，这分别与着床前胚胎进入子宫的时间和该物种子宫内膜最大敏感性时期一致。在这些天，除了毛细血管外，整个子宫内膜基质和子宫肌层中的酶活性也明显降低。相比之下，通过在子宫输卵管交界处结扎来阻止天然胚胎进入子宫对微绒毛突起发育没有影响，但仅在着床后立即导致腔上皮和腺上皮中的酶活性显著降低。与对照组的低立方上皮相比，炔诺酮处理的大鼠在最大敏感性当天的子宫腔显得高度扩张，内衬高柱状上皮。研究结果表明：（a）子宫腔上皮碱性磷酸酶活性与子宫内膜敏感性之间存在相关性；（b）炔诺酮处理后腔上皮和腺上皮中的酶活性完全抑制可能与上皮细胞通透性特征改变有关，这与最大敏感性当天微绒毛突起的缺失和子宫腔高度扩张一起，提示腔液的内吞/胞饮作用、腔闭合、囊胚滋养层与腔上皮的附着以及腺上皮的分泌活性受到抑制；（c）子宫内膜表面的微绒毛突起发育与子宫内活胚泡的存在无关；（d）微绒毛突起的完全缺失表明子宫内膜缺乏敏感性，但它们的存在不一定表明大鼠子宫内膜已致敏。
