The nuclear and developmental competence of cumulus–oocyte complexes is enhanced by three‐dimensional coculture with conspecific denuded oocytes during in vitro maturation in the domestic cat model

Abstract

Contents The objective of the study was to assess the efficacy of coculture with conspecific cumulus‐denuded oocytes (CDOs) during in vitro maturation in a three‐dimensional system of barium alginate microcapsules on the in vitro embryo development of domestic cat cumulus–oocyte complexes (COCs). In Experiment I, COCs were cocultured with conspecific CDOs or cultured separately in a 3D system for 24 hr of in vitro maturation, before assessing the meiotic progression. In Experiment II, the in vitro fertilization of COCs and CDOs was carried out with chilled epididymal spermatozoa and the presumptive zygotes were cultured in vitro separately for 7 days in 3D microcapsules before assesment of embryonic development. The results showed that the viability was maintained and that meiosis was resumed in the 3D culture system. The presence of CDOs during in vitro maturation improved the meiotic competence of the COCs, since the proportions of telophase I/metaphase II were higher than that in the groups cultured separately. The enrichment of the maturation system by companion oocytes also enhanced the ability of COCs to develop into embryos, and increased the percentages of morula and blastoycst stages. The COCs cocultured with CDOs developed at higher rates than the COCs cultured separately and the CDOs themselves. The beneficial effects of coculture with conspecific CDOs were presumably due to the paracrine action of some secreted factors that enhanced many molecular patterns related to the complex of cumulus oophorous cells. Further investigations to understand how the 3D microenvironment can influence the features of oocytes and embryos are required.

Nuclear competence and genetic expression of growth differentiation factor‐9 (GDF‐9) of canine oocytes in 3D culture

“…These encouraging results suggest a positive role of alginate microcapsules in providing better environmental conditions for a prolonged culture of oocytes in vitro. As already reported in other species, biocompatible structures can enhance the maintenance of the physiological architecture of female gametes and their molecular, metabolic and developmental competence (Desai et al, 2010;Morselli, Luvoni, & Comizzoli, 2017;Pangas et al, 2003). In comparison with the traditional 2D culture (microdrops of medium in Petri dishes or multiwell), the 3D systems sustain the survival and the growth of cultured cells, promoting the cytoplasmic and nuclear maturation of oocytes and the subsequent embryo development.…”

A new three‐dimensional glass scaffold increases the in vitro maturation efficiency of buffalo (Bubalus bubalis) oocyte via remodelling the extracellular matrix and cell connection of cumulus cells

“…Previous studies showed that the 3D barium alginate microcapsules were used to culture feline oocytes (Morselli, Canziani, Canziani, Vigo, & Luvoni, 2017) and domestic cat oocytes (Morselli, Luvoni, Luvoni, & Comizzoli, 2017) to improve the cumulus-denuded oocyte full competence. Meanwhile, the 3D culture systems were also used in buffalo preantral follicles with collagen gel (Sharma, Dubey, & Meur, 2009) and the denuded oocytes with ovarian tissue (Feng, Shi, Yang, & Wang, 2013).…”

The never‐ending search of an ideal culture system for domestic cat oocytes and embryos

“…Our work on 3D barium alginate microcapsules for the in vitro culture of feline oocytes gave encouraging results in terms of oocyte full nuclear maturation (Morselli, Canziani, Vigo, & Luvoni, 2017) and embryo development (Morselli, Luvoni, & Comizzoli, 2017), together with a significant positive effect of co-culturing fresh COCs with companion denuded ad hoc oocytes.…”

“…With the aim of recreating a physical contact between gametes or embryos and somatic cells, different co‐culture systems (granulosa and oviductal cells: Chigioni, Perego, & Luvoni, ; Roth, Donoghue, Byers, Wildt, & Munson, ; Swanson, Roth, & Godke, ) were tested. In addition, co‐culture of cat COCs with cumulus denuded oocytes as companion cells gave promising results in terms of meiosis resumption and embryo development rates (Godard, Pukazhenthi, Wildt, & Comizzoli, ; Morselli, Luvoni, & Comizzoli, ). Same beneficial effects of the co‐culture have been obtained with embryos cultured in groups rather than alone (Spindler & Wildt, ).…”