Endocrine and paracrine controls of canine follicular development and function

Songsasen, Nucharin; Nagashima, Jennifer; Thongkittidilok, Chommanart

doi:10.1111/rda.12858

Cited by 9 publications

(5 citation statements)

References 54 publications

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“…A mature (tertiary) follicle, or Graaf follicle, consists of a connective membrane (theca) and a multilayered epithelium (granular layer). Inside the Graafian follicle is a large cavity filled with follicular fluid and an egg-bearing tubercle located on the inner lateral wall of the follicle (Berezovs'kyj & Harenko, 2017;Songsasen et al, 2017).…”

Section: Resultsmentioning

confidence: 99%

Advantages and difficulties of ultrasound analysis to determine the fertile period in bitches

Holubiev,

Skliarov,

Pérez-Marín

et al. 2023

TAVM

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Definition the fertile period is one of the most important factors contributing to fertilization. Therefore, this analysis is important to solve the problem of infertility. The methods that available today do not provide the expected result, because the vast majority of unsuccessful mating result are related to the incorrect determination of the ovulation period. Therefore, it is important to assess the condition of the ovaries, and the prospect is ultrasound examination, which is an effective method of monitoring the reproductive organs. Ultrasound analysis is a non-invasive and effective method to establish the fertile period in bitches which makes it possible to track changes in the ovaries, detect follicles, their number, and determine the true (morphological) signs of ovulation. Clinicalvisual and hormonal studies which are based on the indirect determination of the optimal period of female insemination have the advantages in compare with vaginal cytology. Particularly, the use of ultrasound in real time allows to visualize the morphological changes of the ovaries and uterus -the irregular shape of the ovaries with large (0.6-1.2 cm) anechoic structures of a rounded or oval shape with a thin capsule, thickening of the endometrium (up to 0.5-0.8 cm) with a hypoechoic structure of the uterine horns. However, in our research we encountered certain difficulties, which turned out to be the same as other authors. Echography of the ovaries can seem a bit complicated, because the follicles that persist in them have a picture similar to that before and after ovulation. Some ovulated follicles do not always completely collapse (fall) during ovulation and are gradually replaced by luteal tissue while maintaining an echogenic picture on the days of the next ovulation. Non-ovulated follicles can complicate sonography interpretation. To diagnose ovulation, an ultrasound analysis should be performed twice a day, which is inconvenient for the owners. But if the ultrasound test is carried out less often than aforementioned number, there is a risk to miss the moment of ovulation, because the follicles before and after ovulation are very similar. An even more significant problem is the location of the ovaries in bitches -costovertebral angle surrounded by fat and an ovarian sac, which can create technical difficulties. In addition, this diagnostic approach may be more difficult in fat or very large dogs, as well as in dogs with thick skin (Shar Pei, Newfoundland).

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Section: Resultsmentioning

confidence: 99%

Advantages and difficulties of ultrasound analysis to determine the fertile period in bitches

Holubiev,

Skliarov,

Pérez-Marín

et al. 2023

TAVM

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“…However, when we examined mRNA expression of VEGF receptors ( Flt‐1 and KDR ) ) in ovarian cortices, we detected mostly comparable levels of mRNA transcripts between the age groups. There was a modest increase in KDR mRNA in tissue from peri‐pubertal compared to pre‐pubertal donors (Songsasen et al, ;. in press).…”

Section: Discussionmentioning

confidence: 99%

Responsiveness of intraovarian dog follicles in vitro to epidermal growth factor and vascular endothelial growth factor depends on ovarian donor age

Thongkittidilok

Wildt

Songsasen

2016

Reprod Domestic Animals

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ContentsWe investigated the influence of epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) on in vitro follicle development within ovarian cortices recovered from pre-pubertal (≤6 months) versus peri-pubertal dogs (≥10 months).Ovarian cortices were cultured for 3 or 7 days in EGF (0 or 10 ng/ml) and VEGF (0, 0.1 or 1 ng/ml) and subjected to histological and apoptosis analyses. Fresh cortices from the same dogs served as "non-cultured controls" (NCC) and were evaluated similarly.The response of ovarian follicles to growth factors differed between pre-pubertal versus peri-pubertal tissues. For pre-pubertal dogs, percentage of structurally normal follicles in cortices cultured for 3 days in low VEGF (0.1 ng/ml) and EGF alone was comparable to that of the NCC. Follicle density declined in all cultured groups even after 3 days. Primary follicle diameter in all cortices cultured for 7 days, except in low VEGF, was smaller than that of the NCC, and percentage apoptotic follicles sharply increased in all treatment groups compared to the NCC. For peri-pubertal donors, percentages of structurally normal follicles decreased in all culture treatments at 3 and 7 days of incubation compared to the NCC. However, more normal follicles were found in cortices cultured in low VEGF and the two VEGF and EGF combinations than in the absence of growth factors or with EGF alone. Culture reduced the density of developing follicles, but follicle diameter was similar to that of the NCC. TUNEL analysis revealed that high-VEGF (1 ng/ml) treatment protected follicles against apoptosis, with the proportion of apoptotic follicles at Day 7 being comparable to that of the NCC. The findings demonstrate that the response of ovarian cortices to growth factor supplementation varied between pre-pubertal versus peri-pubertal donors.

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“…Os oócitos primários apresentam acentuada quantidade de mitocôndria, ocasionando aumento da atividade metabólica; aumento gradativo dos grânulos lipídicos com função ainda desconhecida, podendo ser uma fonte de reserva nutricional durante o desenvolvimento embrionário (SONGSASEN;WILDT, 2007).…”

Section: Fisiologia Da Ovulaçãounclassified

“…Os fatores que desencadeiam o início do crescimento folicular não são bem compreendidos. No entanto, uma vez que se inicia o processo de foliculogênese com predomínio hormonal, o folículo só pode ovular ou sofrer atresia, caracterizada por morte folicular (SONGSASEN et al, 2017). Estabelecida a onda de crescimento folicular, diminui a reserva de folículos primordias quiescentes, sendo um estádio irreversível para a vida reprodutiva do animal (MONNIAUX, 2016).…”

Section: Fisiologia Da Ovulaçãounclassified

Morfofisiologia Ovariana Das Cadelas

Zoppei¹,

Neto²,

Oliveira³

et al. 2019

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RESUMO As cadelas são monoestrais, poliovulatórias e não sazonais, cujo ciclo estral é regulado por mecanismos de feedback entre neurônios e células secretoras do eixo reprodutivo (Hipotálamo-Hipófise-Ovários). Seus ovários são formandos pela migração das células germinativas até a crista gonadal, povoando os cordões sexuais, que contribuem como células foliculares (Células da Granulosa), que envolvem o oócito, diferenciando-se em Células do Cumulus. Adicionalmente, há as Células da Teca que se desenvolvem em camadas internas e externas. Os folículos permanecem na camada cortical, enquanto que na medular há tecido conjuntivo, nervos e vasos sanguíneos. No pico de Hormônio Luteinizante ocorre a liberação do oócito (ovulação), enquanto que a folículogenese é estimulada pelo Hormônio Folículo Estimulante. Diferentemente de outros mamíferos, a oogênese das cadelas ocorre até dois meses após seu nascimento, pois há células em proliferação na região cortical do ovário, observando um aumento importante dos grânulos lipídicos, resultando em uma aparência escura ao oócito, e apresenta ainda folículos polioocitários, que diminuem durante a senilidade. O aumento das concentrações séricas de Estradiol folicular culmina em alterações de comportamento das cadelas no estro, cujas fases do ciclo estral poderiam ser detectadas pela citologia vaginal. Concluí-se que o conhecimento da anátomo fisiologia dos órgãos reprodutivos das cadelas, bem como a interação endócrina para o controle do ciclo estral, é importante para o manejo reprodutivo eficiente, para o controle da superpopulação canina, para o uso correto de biotécnicas e/ou controle de enfermidades reprodutivas. PALAVRAS-CHAVE: Ciclo estral; Ovário; Reprodução canina.

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Endocrine and paracrine controls of canine follicular development and function

Cited by 9 publications

References 54 publications

Advantages and difficulties of ultrasound analysis to determine the fertile period in bitches

Advantages and difficulties of ultrasound analysis to determine the fertile period in bitches

Responsiveness of intraovarian dog follicles in vitro to epidermal growth factor and vascular endothelial growth factor depends on ovarian donor age

Morfofisiologia Ovariana Das Cadelas

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