Insulin-like growth factor 1 and estrogen from cumulus cell culture increases the success of in vitro fertilization in cattle.

BACKGROUND

Ovaries have the ability to produce insulin-like growth factor-1 (IGF-1) and estrogen, but both of these factors can also be produced through monolayer cell cultures of cumulus oophorus tissue with the addition of precursor materials such as fetal calf serum (FCS) or bovine serum albumin (BSA).

AIM: This study aimed to determine the bioactivity of IGF-1 and estrogen obtained from bovine cumulus cells in the context of in vitro fertilization (IVF).

METHODS

Cumulus cells were harvested from ovarian follicles measuring 2-6 mm and cultured in TCM 199 supplemented with 10% FCS and 10% BSA. The IGF-1, estrogen, and progesterone levels were quantified using the immunoradiometric assay and radioimmunoassay techniques. To lower progesterone concentrations within the culture, a binding technique using antiprogesterone (anti-P4) coated tubes was applied. The culture media served as both a supplement for IVF and an environment for embryo culture. The study assessed the mitogenic and antiapoptotic properties of IGF-1 and estrogen by measuring the reduction of apoptosis in embryos. Findings revealed that incubating for 6 days resulted in the greatest cell monolayer confluency.

RESULTS

The anti-P4 effectively reduced progesterone levels in the culture of cumulus cells. The cleavage rates for embryos with and without progesterone absorption were 27.48% and 53.61%, respectively, whereas the rates of morula embryos increased from 5.73% to 27.59%. Additionally, supplementation decreased apoptosis rates from 70.58% to 31.01%.

CONCLUSION

In summary, the monolayer culture of bovine cumulus cells generated IGF-1 and estrogen, which functioned as mitogenic agents, positively influencing IVF outcomes and embryo development while significantly decreasing apoptosis in the embryos.