Scanning electron microscopic and morphometric analysis of the guinea pig uterine luminal surface: Cyclic and ovarian steroid-induced modifications

Abstract

A morphometric and scanning electron microscopic analysis of endometrial, luminal topographical changes of cyclic and ovariectomized, ovarian steroid-treated guinea pigs was undertaken to determine the effects of cyclic endocrine influences on the uterine surface features recognized to be involved in the process of interstitial blastocyst implantation. Estrogenic stimulation of the uterine epithelial layer induced microvillus growth and closed the endometrial gland openings on the luminal surface. Progestins antagonized these parameters, as indicated by short, sparse microvillus formation over a flat luminal uterine surface on which gland openings were both numerous and prominent. The combined effects of estrogen and progesterone therapies induced luminal epithelial changes resembling those characterizing the cyclic uterine surface at the time of blastocyst implantation. These data indicate that the cyclic alterations in the uterine luminal surface are directly regulated by ovarian steroid hormones, and that these changes in surface structure are synchronized and directly involved in the preparation for blastocyst-uterine interaction during the nidatory process in this species. Anat. Rec. 252:205-214, 1998. 1998 Key words: uterus; scanning electron microscopy; guinea pig; estrogens; progestins Scanning electron microscopy (SEM) has been used to study the luminal surface morphology of the oviduct (Dirksen and Satir 1972;Ferenczy et al., 1972;Kanagawa et al., 1972;Ludwig et al., 1972; Patek et al., 1972a,b;Dirksen, 1974;Rumery and Eddy, 1974), uterus (Psychoyos and Mandon,1971;Hafez, 1972Hafez, , 1973 Johnnisson and Nilsson, 1972;Anderson et al., 1975;Jones and Hamer, 1975;Ferenczy, 1974Ferenczy, ,1976Motta and Andrews, 1976;Garris, 1984d), and vagina (Kanagawa et al., 1972;Parakkal, 1974) in a number of species, including human (Ludwig et al., 1972, at various stages of the reproductive cycle. Cyclic changes in the rat uterine surface structure are recognized to be under ovarian steroid hormone control (Anderson et al., 1975). While estrogens potentiate microvillus formation by increasing both the number and length of each cell process, progesterone is recognized to induce a diminution in the density and length of uterine epithelial microvilli. As a result, the apical cell surface and intercellular borders of the epithelial cells are more pronounced under the influence of progestins than estrogens. However, the short cycle length and the lack of a functional corpus luteum following ovulation in the rat does not allow for the evaluation of the uterine luminal surface changes which occur as a result of estrogen and progesterone interaction during the prolonged luteal phase of the reproductive cycle.

Low-Dose Aspirin and Uterine Natural Killer Cells in Mice at Day Seven of Pregnancy

“…Prostaglandins affect the endometrium, resulting in the destruction of the CL and as a result, a decrease in blood progestrone levels (2,3). Prostaglandin inhibitor drugs such as aspirin extend the duration of CL activity in pregnant mice due to the pause of luteolysis (4). The results of this study indicated that the administration of low-dose aspirin increased the level of estrogen compared to the control group, resulting in a significant statistical difference (P < 0.05); also, evaluating the results of progesterone determination showed a significant difference between the control and experimental groups (P < 0.05).…”

“…Aspirin is one of the major drugs that inhibits the activity of prostaglandins. Prostaglandin inhibitor drugs inhibit the luteolysis process that leads to the prolongation of the CL activity in pregnant mice (1)(2)(3)(4)(5)(6). Natural killer (NK) cells are one of the most important cell populations of the innate immune system with diverse effector functions.…”

“…Steroidal hormones cause major alterations in the endometrium and directly affect the uterus receptivity for accepting the blastocyst (4,12). The differentiation of uterine NK (uNK) cells is regulated indirectly through estrogen and progesterone (7,13).…”

Arsenic-induced toxicity in the endometrium of adult albino rat and the possible role of human chorionic gonadotropin hormone

“…However, in the present work, the surface epithelial cells became flattened with less dense microvilli in the arsenic-treated group. Estrogen proved to be responsible for the convex appearance of the epithelial surface and stimulated the growth and density of apical microvilli [25].…”

Scanning Electron Microscopic Changes of the Canine Uterine Luminal Surface during Oestrus and Late Metoestrus

“…Scanning electron microscopy (SEM) has been used to study the luminal surface morphology of the uterus at various stages of the oestrous cycle in a number of species, including human (Hafez 1973; Wu et al 1976; Lescoat et al 1984; Ferreira‐Dias et al 1994; Garris 1998; Spornitz et al 1999). However, the present authors are not aware of any such studies having been performed in the dog.…”