Recombinant activin A enhances the growth and survival of isolated preantral follicles cultured three-dimensionally in extracellular basement matrix protein (matrigel) under serum-free conditions

Abstract

Development of in vitro technologies that will allow the culture of early stage follicles before antral stage is an essential part of research in reproductive biology in order to understand the ovarian folliculogenesis better. Current evidence suggests that oocyte and somatic cells-derived growth factors interacting with each other and extracellular matrix proteins at paracrine level are involved in this early, gonadotrophin-independent phase of follicle growth. Basement membrane matrix protein (Matrigel™) is a soluble gel rich in extracellular matrix proteins and growth factors. Activin A promotes preantral follicle growth in vivo by inducing the proliferation of granulosa cells and by upregulating the expression of FSH receptor and aromatase enzyme. We hypothesized that activin A and matrigel may provide a better in vitro environment for early stage preantral follicles. Preantral follicles isolated from 14-21 day old BALB/c mice were cultured in matrigel ± activin A for four days. The growth (119.4% versus 45.4%, p < 0.05; respectively) and survival rates (76.3% versus 43.7%, p < 0.05; respectively) of the follicles treated with activin A were significantly higher compared to those without activin A. These results suggest that Activin A and matrigel provide a better in vitro milieu for the growth of isolated ovarian follicles.

Activin effects on follicular growth in <i>in vitro</i> preantral follicle culture

“…The autocrine/paracrine actions of activin on granulosa cells were reported as follows ; induction of FSH-R (9, 10) and LH receptor (31), enhancement of FSH induced aromatase activity (32), suppression of follicle atresia and premature luteinization (32). Our analysis of follicular diameter in in vitro preantral follicle cultures has clearly demonstrated that activin stimulates follicular growth almost 4 days earlier than the other groups, which is fundamentally in accordance with previous reports (13,16,18). Four days later, follicles in the non-activin groups started growing at the same rate as the activin group, and progressed to plateau at the same diameter by day 10 in culture.…”

Phase-related differences in egg production of the migratory locust regulated by differential oosorption through microRNA-34 targeting activinβ

“…In Drosophila, gbb and dpp are essential for GSC maintenance in the ovary [40] and dpp also functions in the formation of eggshell structure [41]. In mammals, activin A fosters granulosa cell proliferation, preantral follicle growth and antral formation, as well as increase in the survival of preantral follicles by decreasing the proportion of atretic follicles [42,43]. Another ligand, Nodal, was found to promote granulosa cell apoptosis and follicular atresia [44].…”

A Simplified Method for Three-Dimensional (3-D) Ovarian Tissue Culture Yielding Oocytes Competent to Produce Full-Term Offspring in Mice

“…Interestingly, our results showed that addition of activin A to our membrane culture system without Matrigel (our “A condition”) did not enhance oocyte quality, suggesting that exogenous activin A functions only when the ovarian microenvironment is properly organized and maintained. Previous studies have demonstrated that a combination of Matrigel and activin A synergistically enhances in vitro follicle growth compared to conditions utilizing individual ECM proteins plus activin A [ 8 ], or Matrigel alone [ 45 ]. The ECM proteins act as a reservoir for growth factors, communicate with the intracellular cytoskeleton, and transmit growth factor signals [ 9 , 12 ].…”