Relationships of changes in B-mode echotexture and colour-Doppler signals in the wall of the preovulatory follicle to changes in systemic oestradiol concentrations and the effects of human chorionic gonadotrophin in mares

Abstract

A duplex grey-scale and colour-Doppler ultrasound instrument was used to study the changes in the wall of the preovulatory follicle in mares. When the follicle reached $35 mm (hour 0), mares were randomized into control (n 5 16) and human chorionic gonadotropin (hCG)-treated (n 5 16) groups. The hCG treatment was given at hour 0. Scanning was done every 12 h until hour 36, every hour between hours 36 and 48, and every 12 h thereafter until ovulation. Blood was sampled every 12 h for oestradiol assay. During the period 0-24 h post-treatment, oestradiol concentrations decreased in the hCG group and increased in the controls (significant interaction). During the period 0-36 h post-treatment, thickness and echogenicity of the granulosa increased in the hCG group but not in the controls. During the period 36 to 12 h before ovulation, granulosa and colour-Doppler end-points increased in the control and hCG groups (hour effects), while oestradiol was decreasing in both groups. The prominence and percentage of follicle circumference with an anechoic band peripheral to the granulosa and colour-Doppler signals in the follicle wall, indicating arterial blood flow, decreased during the period 4 to 1 h before ovulation (hour effects). Results indicated that the ultrasonographic changes of the wall of the preovulatory follicle were not associated temporally with changes in oestradiol concentrations and prominence of an anechoic band, and colour-Doppler signals decreased during the few hours before ovulation. The hypothesis that the latter portion of the ovulatory LH surge has a negative effect on systemic oestradiol was supported by the immediate decrease in oestradiol concentrations when hCG was injected.

Follicular blood flow, antrum growth and angiogenic mediators in mares from ovulation to deviation

“…Follicle selection and deviation in mares (Gastal et al, 1997(Gastal et al, , 1999b(Gastal et al, , 2006Donadeu and Ginther, 2004), and cattle (Ginther et al, 1996;Fortune et al, 2001), depended on comparing diameter of recruited follicles but other morphological dimensions of the follicle such as follicle area, volume and follicle antrum growth had not received much interest in such species. Follicular antrum growth was studied in primate (Wulff et al, 2002) and recently several hypotheses were tested for explaining the development of follicular fluid within the antrum (Rodgers and Irving-Rodgers, 2010).…”

Aplicação da ultrassonografia colorida doppler em programas de transferência de embriões equinos

“…Considerando que o folículo de éguas induzidas com hCG apresentam um aumento na perfusão sanguínea nas primeiras 24 horas e ovulam em média entre 36 e 42 horas pós-tratamento (GASTAL et al, 2006b), a US Doppler permite a avaliação precoce da eficácia de tratamentos indutores de ovulação.…”

“…GINTHER et al (2006a) descreveram que folículos que evacuam lentamente, com presença de septos e compartimentos, apresentam proeminente vascularização ao longo de toda sua circunferência, inclusive na região do ápice folicular. Já durante uma evacuação normal, a perfusão sanguínea diminui poucas horas antes da OV e concentra-se na base do folículo (GASTAL et al, 2006b) Ciência Rural, v.41, n.6, jun, 2011.…”

Novel prospects for evaluation of follicle wall blood flow using color-Doppler ultrasonography

“…In reproduction, vascular events in the preovulatory follicle (POF) and subsequent corpus luteum (CL) formation are crucial for proper functioning of reproductive events (Bollwein et al, 2002;Acosta et al, 2003;Acosta and Miyamoto, 2004;de Tarso et al, 2015). Follicle blood flow has been shown to be predictive of the following: subsequent CL blood flow and plasma progesterone concentrations (de Tarso et al, 2015), developmental and ovulatory status of follicles (Brannstorm et al, 1998;Acosta and Miyamoto, 2004;Gastal et al, 2006;Acosta, 2007;Siddiqui et al, 2010;Gastal and Gastal, 2011), establishment of pregnancy and/or fertility (Dickey, 1997;Silva et al, 2006;Siddiqui et al, 2009a), and maturity of oocytes and success of in vitro fertilization and embryo development (Bhal et al, 1999;Coulam et al, 1999;Huey et al, 1999;Ginther et al, 2007b;Siddiqui et al, 2009b) in several species such as cattle, horses, and women.…”

“…This method of evaluation has been used as a gold standard test to compare results with subjective methods (Ginther and Utt, 2004;Ginther et al, 2007a). The second methodology involves the subjective evaluation (percentage or score system) of the vascular perfusion of a structure, based on the estimated proportion of the structure with color signals, according to the sonographer's judgment (Bhal et al, 1999;Gastal et al, 2006;Ginther, 2007).…”