Classification of Bovine Follicles Based on the Concentrations of Steroids, Glucose and Lactate in Follicular Fluid and the Status of Accompanying Follicles

Abstract

Abstract.A simple and clear means to identify the physiological status of follicles is essential for study of follicular biology. In the present study, we verified a novel classification procedure based on analysis of the follicular population and glucose concentration in follicular fluid (FF) as an alternative method to classify bovine follicles. Paired ovaries were collected from heifers, and the number of follicles and stage of the CL were recorded. Follicles were initially divided into the following 3 groups according to diameter and the ratio of E2 and P4 (E/P): E2 active (E-A: E/P≥1), E2 inactive (E-I: E/P<1, ≥8.5 mm) and small follicles (E/P<1, <8.5 mm). E-A follicles were easily identified as E2-rich dominant follicles and were further classified according to diameter and stage of the CL as early dominant (EDF: <8.5 mm), dominant (DF: ≥8.5 mm, stages I-III) or preovulatory follicles (POF: ≥8.5 mm, stage IV). E-I follicles were classified as follows based on the status of the accompanying follicles: early atretic (EAF: without an E-A follicle), mid-atretic (MAF: with an EDF or DF) and late atretic follicles (LAF: with an EAF or POF). The follicular P4 concentrations of the MAF and LAF were significantly higher compared with that of the EAF, while follicular glucose concentration of the LAF was lower compared with those of EAF and MAF, indicating that this classification can be used to distinguish early atretic follicles from more advanced atretic follicles. Small follicles were classified as growing (GF: without E-A follicles) and suppressed small follicles (SSF: with E-A follicles). The SSF was easily identifiable by this procedure, but some GF populations likely contained SSF. To identify true GF, the ratio of E2 in the GF and accompanying EAF may be used. In conclusion, analysis of the follicular population in conjunction with biochemical indices such as steroid and glucose concentrations in FF provides a simple and accurate means of classifying bovine follicles. battoir-derived ovaries have been used extensively as sources of oocytes for embryo production in vitro. Ovaries also provide useful materials for investigating the physiological functions of follicles. Although recent development of ultrasonography enables researchers to monitor development of follicles in real time, follicular samples derived from abattoir-harvested ovaries continue to be cheap and valuable materials for investigating the biochemical natures of follicular fluid (FF) and ovarian functions such as gene/ protein expression. For this reason, a simple and accurate method to determine the physiological status of follicles is necessary. To date, some follicular classification methods have been advocated. These methods are based on morphological, histological and biochemical criteria, but none of them are without faults.Histological examination employs the incidence of pycnosis in granulosa cell nuclei and the degree of granulosa/thecal integrity as the criteria [1]. Although this method is sensitive enough to detect a slight sign o...

Corpus luteum development and its morphology after aspiration of a preovulatory follicle is related to size and steroid content of the follicle in dairy cows

“…We showed in the current study for the first time that assessing the rate of CL development after the taking of follicle fluid samples from a pre-ovulatory follicle, allows discrimination between follicles with different qualities, which might be taken as the same group if they were judged commonly on the basis of oestradiol and progesterone concentrations (Lohrke et al 2005, Nishimoto et al 2009 or morphology (Acosta 2007). Both groups of pre-ovulatory follicles (with or without subsequent development of a corpus luteum) showed expected, or even higher, progesterone concentrations in their FF (Lohrke et al 2005;Nimz et al 2009).…”

“…Concentrations of progesterone and oestradiol as well as their ratio in the FF as well as follicle size are commonly used to define the developmental stage of a follicle (Nishimoto et al 2009). We showed in the current study for the first time that assessing the rate of CL development after the taking of follicle fluid samples from a pre-ovulatory follicle, allows discrimination between follicles with different qualities, which might be taken as the same group if they were judged commonly on the basis of oestradiol and progesterone concentrations (Lohrke et al 2005, Nishimoto et al 2009 or morphology (Acosta 2007).…”

“…However, most of these studies were performed in heifers or with material of unknown origin, collected at the slaughter house. As usual, the developmental stage of follicles recovered at slaughter houses are defined retrospectively by their hormone content in the follicular fluids (Nishimoto et al 2009), but of course their real further development cannot be ascertained. By using the ultrasound technique we have the opportunity to observe the follicle and CL development without any influence on their physiology (Roelofs et al 2004).…”

Estradiol supports in vitro development of bovine early antral follicles

“…We measured the concentration of E 2 in bovine FF previously and found the highest E 2 concentration to be about 0.1-0.2 mg/ml. In addition, the E 2 concentration in bovine antral follicles reportedly ranges from 0 to 0.3 mg/ml (Ouellette et al 2005, Monniaux et al 2008, Nishimoto et al 2009, Green et al 2011. Furthermore, Bridges et al (2005) reported that when bovine follicle cells were cultured in vitro, the concentration of E 2 secreted was 0.2 mg/ml.…”

Study the Effects of Follicular Size on some Biochemical Follicular Fluid Composition in She Camel (Camelus Dromedarius)

“…It produces from local substances produce locally, and part of this fluid is filtrated from blood serum that related with the metabolic activities of follicular cell (Gerard et al, 2002). Therefore, the compositions of follicular fluid are alike but not identical to blood plasma (Nishimoto et al, 2009). The ovary cells produce soluble substance like steroids hormone, growth factors (Fortune et al, 2004) inhibition factors (Aruna kumari et al, 2007), ionic and fat substances (Nandi et al, 2008), as well as some of minerals and salts (Sharma and Vasta, 1998).…”