Follicular development and morphological changes in the vaginal epithelium during the estrous cycle ofGalea spixii

Abstract

The current study aimed to determine if characteristics observed in vaginal cytology during the estrous cycle of female SYT cavies corresponded with proliferation of the vaginal epithelium, characterized by proliferating cell nuclear antigen (PCNA) immunolocalization, and with follicular development at different phases of the estrous cycle. After determining estrous cycle phases by vaginal cytology, females were euthanized at metestrus, diestrus, proestrus, and estrus. Histological study of the vaginal epithelium and ovary were then performed. Immunohistochemistry for PCNA in vaginal tissue at each cycle phase was also performed. Superficial cornified cells and early post-ovulatory follicles were found at estrus. Few nuclei below the enucleate superficial cells were immunoreactive to PCNA. At metestrus, the vaginal epithelium underwent desquamation and lost the superficial cornified cells; basal and intermediate cells appeared, and the post-ovulatory follicle formed an early corpus luteum. No PCNA immunoreactivity was observed. At diestrus, the corpus luteum was developed, and the vaginal epithelium contained basal and intermediate cells. There was PCNA immunoreactivity in the cellular nucleus in the germinative stratum of the epithelium. Because of the growth and maturation of ovarian follicles, the vaginal epithelium suffered intense proliferation at proestrus. Vaginal cytology revealed large intermediate cells and nucleated and enucleated superficial cornified cells. In the ovary, mature follicles were present. More apparent immunoreactivity of PCNA in the germinative layer was found. In summary, we inferred that vaginal exfoliative findings matched the proliferation process of the vaginal epithelium. PCNA immunolocalization occurred as well as corresponding follicular development in the ovaries.

Morphology of the genital organs of the female red‐rumped agouti (Dasyprocta leporina, Linnaeus, 1758) during estrous cycle phases and in advanced pregnancy

“…The females were submitted to daily colpocytological examination between 7 and 8 a.m. to identify the current phase of the estrous cycle (proestrus n = 5, estrus n = 5, metestrus n = 5, and diestrus n = 5) of each individual. Test slides were stained using fast panoptic techniques (LaborClin®, São José do Rio Preto, SP, Brazil; Santos et al, ). Proestrus was identified by the predominance of large intermediate cells; estrus was identified by the predominance of superficial cells; metestrus was identified by the prevalence of parabasal cells and large numbers of neutrophils; and diestrus was identified by mostly small and large intermediate cells, with the presence of neutrophils and parabasal cells (Santos et al, ).…”

“…Slices of 5–7 μm thickness were cut, mounted on slides, and stained with hematoxylin and eosin, Gomori's trichrome, Alcian‐Mallory, or periodic acid‐Schiff (PAS) and examined using a light microscope. Microscopic examination of the ovaries was important to confirm the estrous cycle phase, follicular development, and presence of corpora lutea (CL) (Maia et al, ; Moura et al, ; Santos et al, ). The thickness of the muscular layer of the uterine tube (infundibulum, isthmus, and ampulla) and the diameter and height of the epithelium of the uterus and vagina were measured using ImageJ1® software (Schneider, Rasband, & Eliceiri, ).…”

Immunolocalization of steroidogenic enzymes in the vaginal mucous of Galea spixii during the estrous cycle

“…The predominant cells in each smear were classified as superficial, large and small intermediate, parabasal and neutrophils throughout the cycle. Then the estrous cycles phases were characterized according the different cell types present in each phase [4, 7, 12, 13]. …”

“…Spix cavy has also been employed as experimental models in research on placental function [2, 6]. Based on vaginal exfoliative cytology, the estrous cycle lasts 14–19 days and the vaginal epithelium undergoes variations related to each estrous cycle phases [4] in concert with ovarian follicular development and ovulation [7]. …”

Conservation of germplasm derived from spix’s yellow-toothed cavies (Galea spixii WAGLER, 1831)

“…The female reaches sexual maturity at 55-90 days on average (Larcher, 1981), presenting a continuous poliestric cycle with a mean duration of 15.8 ± 1.4 days (Santos et al, 2015). The estrus can lasts from 6 to 11 days, and the predominance of cornified superficial epithelial cells can be highlighted through the vaginal cytological examination (Santos et al, 2015), associated to the presence of preovulatory follicles in the ovaries (Santos et al, 2017). Their gestation period lasts 68 days on average, culminating in the birth two to four pups per litter (Larcher, 1981).…”