Pattern of Lactate Production and Steroidogenesis during Growth and Maturation of Mouse Ovarian Follicles in Vitro1

Abstract

A model culture system for the study of follicular metabolism has been developed from existing methods of whole-follicle culture. The modified system mimics the in vivo growth and maturation of mouse ovarian follicles from primary to preovulatory stages and the modulating influences of the LH and FSH. This is the first study to demonstrate ovulation in vitro from individual ovarian follicles. The pattern of follicular lactate production relative to steroidogenesis was studied throughout in vitro follicular development over a period of 6 days. Twenty-four-hour samples of medium from individual follicles were analyzed for lactate and pyruvate by an automated analytical technique, and for estradiol and progesterone by an immunoenzymatic method. Follicles produced remarkably large quantities of lactate and estradiol during FSH-stimulated development in vitro. LH further stimulated lactate production but resulted in a significant decrease in estradiol secretion and an ovulation rate of 30%. Progesterone production was not detectable throughout the culture period, and follicles showed no evidence of pyruvate uptake. These findings demonstrate the validity of using this model culture system for the study of follicular metabolism and provide new information on the pattern of carbohydrate metabolism relative to steroidogenesis during follicular growth and maturation.

Quality and functionality of human ovarian tissue after cryopreservation using an original slow freezing procedure

“…Indeed, aromatase activity, which is required for the synthesis of E2, is present only from secondary follicular stages onwards [17]. Our data are in agreement with previous findings showing a correlation between E2 secretions and follicular growth in cultures of frozen/thawed tissues [2,21,24]. PCNA is a nuclear protein that plays an essential role in cell cycle regulation [50].…”

In vitro follicle growth under non-attachment conditions and decreased FSH levels reduces Lhcgr expression in cumulus cells and promotes oocyte developmental competence

“…By day 9, the last day of culture, follicles can be morphologically differentiated in two types: 1) follicles having reached the large antral stage (diameter >350 μm) with a multilayered compact COC, as assessed under the stereo-microscope; 2) follicles in which an antral cavity was not visible and having a smaller size (ranging from 220 to 350 μm). The antral cavity formation on in vitro follicles reaching approximately 300 μm has also been reported by other researchers using spherical culture systems [22,28]. Therefore, it was decided to divide cultured follicles in two groups (based on their size and presence of antral cavities) for a preliminary analysis of nuclear chromatin configuration.…”

“…Different spherical follicle culture systems have used strategies to prevent the attachment of follicles to the culture wells, with the aim to provide a more natural environment to the growing oocyte [15,18,20,22,24,25,28,[38][39][40][41]. The present study evaluates the impact of culturing follicles in a non-attachment system by comparing gene expression levels in oocytes and their surrounding cumulus cells to those found in a previously characterized attachment follicle culture system and to in-vivo conditions.…”

Methodology and characterization of an in vitro perfusion model for the mouse ovary

“…3b) (Bruning et al, 1981) with a t1/2 of about 2.5 h (Brännström et al, 1987 (Fig. 4) (Neal and Baker, 1973;Boland et al, 1995) and it is possible that some of these ruptured follicles were caused by mechanical trauma during preparation or incubation (Neal and Baker, 1973;Boland et al, 1993 (Brännström et al, 1989). The observation that the ovulation rate can be increased in rat ovaries perfused in vitro by addition of several blood factors such as leukocytes (Hellberg et al, 1991) and bradykinin (Brännström and Hellberg, 1989) …”