scholarly journals Cyclic changes of the ovarian surface epithelium in the rat

Reproduction ◽  
2005 ◽  
Vol 129 (3) ◽  
pp. 311-321 ◽  
Author(s):  
M Gaytán ◽  
M A Sánchez ◽  
C Morales ◽  
C Bellido ◽  
Y Millán ◽  
...  

The ovarian surface epithelium (OSE) plays pivotal roles during ovulation and postovulatory wound repair. In this paper we describe the proliferative activity of the OSE through the estrous cycle in adult cycling rats, by immunohistochemical detection of DNA-incorporated bromodeoxyuridine (BrdU). Immunohistochemical detection of estrogen receptor α (ERα) and progesterone receptor was also performed. The cycle of the OSE consists of a proliferative phase (that lasts for two consecutive estrous cycles) and a quiescent phase of variable duration. Cyclic changes in the OSE were related to the underlying ovarian structure. OSE areas covering growing follicles entered into the proliferative phase during the transition from proestrus to estrus, with the appearance of fast-growing class 1 follicles, destined to ovulate at the end of the current estrous cycle. A labeling index (after pulse-labeling BrdU treatment) of about 7% was maintained throughout the estrous cycle in parallel to follicle growth. Cumulative BrdU-labeling (after daily BrdU treatment) indicated that about 1/3 of the total OSE cell proliferation was related to follicle growth. Following ovulation, OSE cells covering newly-formed corpora lutea showed a labeling index of about 50% that decreased through metestrus and diestrus (about 13% and 3%, respectively), returning to basal levels by proestrus. Cumulative BrdU-labeling indicated that about 2/3 of the total proliferative activity was related to ovulation repair/luteinization. The remaining OSE covering ovarian stroma or structurally regressing corpora lutea of previous cycles showed negligible BrdU labeling. The equivalent proliferative activity found in the OSE covering newly-formed corpora lutea in indomethacin-treated rats lacking rupture of the OSE at the apex, demonstrated that ovulation-triggered proliferation was not dependent on the loss of integrity of the OSE at the ovulation site. OSE cells expressed ERα throughout the cycle, but no differential expression was found between proliferating and quiescent OSE areas. On the contrary, OSE cells did not express PR at any time of the cycle. These data indicate the existence of a cycle of the OSE, related to the cyclic changes in the underlying ovarian structure and strongly suggest that the proliferative activity of the OSE is regulated by local microenvironmental rather than by systemic factors.

2006 ◽  
Vol 188 (2) ◽  
pp. 179-192 ◽  
Author(s):  
Karin A Slot ◽  
Marsha Voorendt ◽  
Mieke de Boer-Brouwer ◽  
Harmke H van Vugt ◽  
Katja J Teerds

In the present investigation, the localization of proteins involved in ovarian apoptosis were studied throughout the estrous cycle in the presence of fluctuating hormone levels. Fas, Fas ligand, Bcl-2, Bax and caspase-3 mRNA expression and proteins were detected in all ovarian tissue extracts, though the amount of protein varied with the phase of the estrous cycle. Fas, Bax and caspase-3 protein levels were highest at diestrus and decreased thereafter towards metestrus. In contrast, Fas ligand and Bcl-2 protein levels were lowest at diestrus and increased toward metestrus. Immunohistochemistry revealed that the staining of the anti-apoptotic protein Bcl-2 was more pronounced in healthy preantral follicles than in atretic follicles. In contrast, the pro-apoptotic proteins Fas, Fas ligand, Bax and active caspase-3 were more predominantly present in atretic follicles. In the ovarian surface epithelium (OSE), Fas, procaspase-3 and Bcl-2 immunostaining appeared independent of the phase of the estrous cycle. Fas ligand and Bax staining was detected particularly during proestrus in OSE cells surrounding the ovulatory follicles, while active caspase-3 was observed only in OSE cells at the postovulatory site during estrus. The proportion of luteal cells that stained positively for Fas, Bax and caspase-3 increased with the age of the corpus luteum, while Fas ligand and Bcl-2 immunostaining was strongest in newly formed corpora lutea and decreased thereafter. In conclusion, the components of the Fas signalling pathway were differentially expressed throughout the estrous cycle in a variety of ovarian cell types, which may correspond to hormone dependent survival mechanisms.


Endocrinology ◽  
2006 ◽  
Vol 147 (5) ◽  
pp. 2338-2345 ◽  
Author(s):  
Joanna E. Burdette ◽  
Sarah J. Kurley ◽  
Signe M. Kilen ◽  
Kelly E. Mayo ◽  
Teresa K. Woodruff

The ovarian surface epithelium (OSE) is a monolayer of cells that surround the ovary and accommodate repeated tear and repair in response to ovulation. OSE cells are thought to be the progenitors of 90% of ovarian cancers. Currently, the total amount of proliferation of the OSE has not been reported in response to one ovulatory event. In this study, proliferation of the OSE was quantified in response to superovulation induced by ip injection of pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) in immature 27-d-old CD1 mice using bromodeoxyuridine (BrdU). BrdU incorporation into the OSE cells was measured from the time of hCG injection for a total cumulative label of 12 h. BrdU incorporation was also measured from the time of PMSG injection for a total label of 60 h to correlate proliferation with specific gonadotropin stimulation. The OSE proliferation was significantly higher in superovulated animals compared with control mice at all time points. Proliferation was also analyzed in discrete anatomical sections and indicated that OSE covering antral follicles and corpora lutea proliferated more rapidly than OSE distal to follicular growth. Finally, apoptosis was assessed in response to ovulation, and virtually no cell death within the OSE was detected. These data demonstrate that the OSE, especially near antral follicles and corpora lutea, proliferates significantly in response to the gonadotropins PMSG and hCG. Therefore, ovarian surface cell division in response to ovulation could contribute to ovarian cancer by proliferation-induced DNA mutations and transformed cell progression.


Zygote ◽  
2006 ◽  
Vol 14 (2) ◽  
pp. 107-117 ◽  
Author(s):  
José R.V. Silva ◽  
Robert van den Hurk ◽  
José R. Figueiredo

SummaryTo examine the possibility that epidermal growth factor (EGF) and its receptor (EGF-R) are expressed throughout folliculogenesis, we studied the presence and distribution of EGF and EGF-R in goat ovaries. Ovaries of goats were collected and either fixed in paraformaldehyde for immunohistochemical localization of proteins, or used for the isolation of follicles, luteal cells and ovarian surface epithelium to study mRNA expression for EGF and EGF-R, using the reverse transcriptase polymerase chain reaction. EGF protein and mRNA were found in primordial, primary and secondary follicles as well as in small and large antral follicles and in surface epithelium, but in corpora lutea only the protein could be detected. Antral follicles expressed EGF mRNA in oocyte, cumulus, mural granulosa and theca cells. For EGF-R, both protein and mRNA were present at all stages of follicular development and in all antral follicular compartments. EGF-R protein and mRNA were also found in corpora lutea and surface epithelium. It is concluded that EGF and its receptor are expressed in goat ovarian follicles at all stages of follicle development, in corpora lutea, and in ovarian surface epithelium.


1917 ◽  
Vol 25 (2) ◽  
pp. 305-321 ◽  
Author(s):  
Leo Loeb ◽  
Cora Hesselberg

1. In the pregnant guinea pig proliferation of the mammary gland becomes regular only at a later stage of pregnancy; namely, during the period following the 24th day of pregnancy. Previous to this period proliferation was absent in the majority of cases. Proliferation of the mammary gland during pregnancy becomes regular only at a period of time which exceeds the duration of the normal sexual cycle unaccompanied by pregnancy. It is probable that pregnancy as well as the presence of living deciduornata and corpora lutea increases the proliferative activity of the mammary gland as compared with the ordinary cycle in non-pregnant animals or in animals lacking corpora lutea and deciduornata. 2. After the completion of pregnancy and in the beginning of secretion some mitotic proliferation may still be present, but it soon ceases, probably as the result of those processes that lead to secretion. While during the period of secretion, notwithstanding the presence of a new pregnancy, mitotic proliferation soon ceases, some proliferative stimulus seems still to be active, which, however, under existing conditions apparently leads only to a mitotic multiplication of nuclei. The latter conclusion is only suggested at the present time and needs confirmation through further studies. 3. In cases in which abortion took place in the first half of pregnancy secretion in the gland was not established; secretion occurred in two animals aborting toward the latter part of pregnancy. In one of these cases, mitotic proliferation of some gland cells was associated with the microscopic appearances of secretion. 4. In guinea pigs castrated during an early period of pregnancy in which pregnancy continued for some time, proliferative changes were absent in the mammary gland. In conjunction with a partial similar effect observed after extirpation of the corpora lutea during pregnancy, we may perhaps attribute the lack of proliferation in some of these cases to the absence of the ovaries. 5. Extirpation of the corpora lutea during pregnancy induces a new ovulation and with it the primary proliferation in the mammary gland; abortion does not necessarily prevent these proliferative changes. Extirpation of the corpora lutea during pregnancy perhaps prevents the secondary proliferative changes in the mammary gland. 6. Five injections of cow's lutein given in relatively large quantities intraperitoneally do not produce proliferation of the mammary gland in the guinea pig.


2012 ◽  
Vol 32 (7) ◽  
pp. 420
Author(s):  
Henrique Boll de Araujo Bastos ◽  
Gabriel de Oliveira Santos ◽  
Murilo Farias Rodrigues ◽  
Angélica Pires Neves ◽  
Luis Augusto Cruz ◽  
...  

2009 ◽  
Vol 296 (3) ◽  
pp. E520-E531 ◽  
Author(s):  
F. Gaytán ◽  
M. Gaytán ◽  
J. M. Castellano ◽  
M. Romero ◽  
J. Roa ◽  
...  

Kisspeptins, the products of the KiSS-1 gene acting via G protein-coupled receptor 54 (GPR54), have recently emerged as pivotal signals in the hypothalamic network triggering the preovulatory surge of gonadotropins and, hence, ovulation. Additional actions of kisspeptins at other levels of the hypothalamic-pituitary-ovarian axis have been suggested but remain to date scarcely studied. We report herein the pattern of expression of KiSS-1 and GPR54 in the human and nonhuman primate ovary and evaluate changes in ovarian KiSS-1 expression in a rat model of ovulatory dysfunction. KiSS-1 and GPR54 mRNAs were detected in human ovarian tissue and cultured granulosa-lutein cells. In good agreement, kisspeptin immunoreactivity was observed in cyclic human and marmoset ovaries, with prominent signals in the theca layer of growing follicles, corpora lutea, interstitial gland, and ovarian surface epithelium. GPR54 immunoreactivity was also found in human theca and luteal cells. Administration of indomethacin to cyclic female rats disturbed ovulation and resulted in a dramatic drop in ovarian KiSS-1, but not GPR54, cyclooxygenase-2 (COX-2), or progesterone receptor, mRNA levels at the time of ovulation; an effect mimicked by the selective COX-2 inhibitor NS398 and rescued by coadministration of PGE2. Likewise, the stimulatory effect of human choriogonadotropin on ovarian KiSS-1 expression was partially blunted by indomethacin. In contrast, KiSS-1 mRNA levels remained unaltered in another model of ovulatory failure, i.e., the RU486-treated rat. In summary, we document for the first time the expression of KiSS-1/kisspeptin and GPR54 in the human and nonhuman primate ovary. In addition, we provide evidence for the ability of inhibitors of COX-2, known to disturb follicular rupture and ovulation, to selectively alter the expression of KiSS-1 gene in rat ovary. Altogether, our results are suggestive of a conserved role of local KiSS-1 in the direct control of ovarian functions in mammals.


2008 ◽  
Vol 63 (5) ◽  
pp. 307-308
Author(s):  
Jay W. Wright ◽  
Tanja Pejovic ◽  
John Fanton ◽  
Richard L. Stouffer

1950 ◽  
Vol 40 (1-2) ◽  
pp. 150-156 ◽  
Author(s):  
F. L. M. Dawson

The genitalia of a control series of nineteen animals, slaughtered for other reasons than reproductive failure, were studied. Of these six were in various stages of pregnancy, one was in a ‘proliferative phase’, being slaughtered probably just before the first oestrus after calving, and twelve represented different phases of the oestrous cycle, more than half exemplifying the last 4 days before heat. Stages were judged from the appearance of the ovaries, and checked in five instances by repeated rectal examinations, and observation of behaviour during life. Of the nineteen uteri eight yielded bacteria on culture, sometimes in moderately high density; from two of them, pure cultures were recovered respectively of Pseudomonas and Neisseria catarrhalis; and in another, probably Proteus was found. No previous records of these three genera at such a site have been found. Only aerobic blood agar plate cultures, and those for tuberculosis organisms were made. Dissection results unequivocally supported the view of Tagliavini in opposition to that taken by Hammond, that the sanguineous elements in post-oestral discharge originated from endometrial extravasation. The cow slaughtered 4 days after heat indicated that congestion disappears from the caruncles before leaving the areas between them. Microscopically, no mast cells, as observed by the Italian workers, could be seen; it appeared that a ‘proliferative phase’ occurs in every cycle during the three pre-oestral days, when gland tissue proliferates from its nadir of development, surface epithelium grows in height, and vascularization progresses. The rate and interrelations of these changes seemed variable. Arterioles appeared to be withdrawn from the superficial mucosa during the secretory phase. Tagliavini's claim to have observed sloughing of epithelium about the 17th day, strictly equivalent to the process of menstruation in the Primates, must on the evidence be regarded with considerable reserve.


Reproduction ◽  
2014 ◽  
Vol 147 (2) ◽  
pp. 189-197 ◽  
Author(s):  
Noriyuki Takahashi ◽  
Wataru Tarumi ◽  
Bunpei Ishizuka

Most of the previous studies on ovarian hyaluronan (HA) have focused on mature antral follicles or corpora lutea, but scarcely on small preantral follicles. Moreover, the origin of follicular HA is unknown. To clarify the localization of HA and its synthases in small growing follicles, involvement of HA in follicle growth, and gonadotropin regulation of HA synthase (Has) gene expression, in this study, perinatal, immature, and adult ovaries of Wistar-Imamichi rats were examined histologically and biochemically and byin vitrofollicle culture. HA was detected in the extracellular matrix of granulosa and theca cell layers of primary follicles and more advanced follicles. Ovarian HA accumulation ontogenetically started in the sex cords of perinatal rats, and its primary site shifted to the intrafollicular region of primary follicles within 5 days of birth. TheHas1–3mRNAs were expressed in the ovaries of perinatal, prepubertal, and adult rats, and the expression levels ofHas1andHas2genes were modulated during the estrous cycle in adult rats and following administration of exogenous gonadotropins in immature acyclic rats. TheHas1andHas2mRNAs were predominantly localized in the theca and granulosa cell layers of growing follicles respectively. Treatments with chemicals known to reduce ovarian HA synthesis induced follicular atresia. More directly, the addition ofStreptomyceshyaluronidase, which specifically degrades HA, induced the arrest of follicle growth in anin vitroculture system. These results indicate that gonadotropin-regulated HA synthesis is involved in normal follicle growth.


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