Activin promotes growth and antral cavity expansion in the dog ovarian follicle

Abstract

Understanding regulators of folliculogenesis remains limited in the domestic dog (Canis familiaris), which challenges our ability to develop in vitro follicle culture systems for canid genome rescue efforts. Here, we investigated the influence of activin on dog follicle development and survival, oocyte quality, and FSH receptor expression in culture. Preantral (150-≤230 µm diameter), early antral (231-≤330 µm), and antral (>330-550 µm) stage follicles were encapsulated in a fibrin-alginate hydrogel with 0, 100, or 200 ng/ml rhActivin plus 0, 0.1, 1, or 10 µg/ml FSH for 12 or 21 d of in vitro culture. All follicle groups increased in diameter (P < 0.05) with activin acting synergistically with FSH to improve (P < 0.05) growth and antral cavity expansion (to >630 µm) in early antral and antral cohorts. This complementary effect was not linked to changes in FSHR mRNA expression (P > 0.05). Although not influencing (P > 0.05) follicle survival or transzonal projection (TZP) density in shorter term 12 d culture, activin in the presence of 1 ng/ml FSH maintained TZP density from the 12 to 21 d interval. Activin also increased oocyte diameter and improved nuclear integrity compared to un-supplemented controls. These results indicate that activin acts synergistically with FSH to promote growth and antral cavity expansion of the dog follicle in vitro, information useful to formulating an effective culture microenvironment for this species.

Improvement Effect of Metformin on Female and Male Reproduction in Endocrine Pathologies and Its Mechanisms

“…The FSH-dependent pathways are also regulated by the members of the transforming growth factor β (TGF-β) family, including activins, inhibins, and anti-Müllerian hormone (AMH). Activins increase the FSH receptor expression and enhance the stimulatory effects of FSH on ovarian steroidogenesis [ 262 , 263 ]. In contrast, AMH and inhibins suppress the stimulatory effects of FSH on folliculogenesis [ 249 , 262 , 264 , 265 ].…”

Intraovarian regulation of folliculogenesis in the dog: A review

“…Mouse pre-antral follicles secrete activin A which, in turn, stimulates granulosa cell proliferation and follicle growth (Bloise et al, 2019). Activin We recently demonstrated that activin A acts synergistically with FSH to support in vitro growth of dog antral follicles during 21-day in vitro culture (Nagashima, Wildt, Travis, & Songsasen, 2019). Furthermore, activin and FSH promote antral cavity expansion in vitro in early and antral follicles but do not support the transition of the pre-antral to antral stage (Nagashima et al, 2019).…”

“…Activin We recently demonstrated that activin A acts synergistically with FSH to support in vitro growth of dog antral follicles during 21-day in vitro culture (Nagashima, Wildt, Travis, & Songsasen, 2019). Furthermore, activin and FSH promote antral cavity expansion in vitro in early and antral follicles but do not support the transition of the pre-antral to antral stage (Nagashima et al, 2019). Finally, activin supports in vitro growth and viability of dog oocytes by sustaining bidirectional communication between the gamete and somatic cells during the 21-day culture (Nagashima et al, 2019).…”

“…Activin A also enhances aromatase activity and proliferation of granulosa cells, maintains granulosa cell–oocyte communication and promotes in vitro pre‐antral follicle growth in the cow (McLaughlin, Bromfield, Albertini, & Telfer, 2010; Telfer, McLaughlin, Ding, & Joo Thong, 2008). We recently demonstrated that activin A acts synergistically with FSH to support in vitro growth of dog antral follicles during 21‐day in vitro culture (Nagashima, Wildt, Travis, & Songsasen, 2019). Furthermore, activin and FSH promote antral cavity expansion in vitro in early and antral follicles but do not support the transition of the pre‐antral to antral stage (Nagashima et al, 2019).…”

“…Furthermore, activin and FSH promote antral cavity expansion in vitro in early and antral follicles but do not support the transition of the pre‐antral to antral stage (Nagashima et al, 2019). Finally, activin supports in vitro growth and viability of dog oocytes by sustaining bidirectional communication between the gamete and somatic cells during the 21‐day culture (Nagashima et al, 2019).…”