Insulin Like Growth Factor 1 and Estrogen from Cumulus cell culture increase the success of in vitro fertilization in cattle

Background: The 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 Foetal 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 levels of IGF-1, estrogen, and progesterone were quantified using the IRMA and RIA techniques. To lower progesterone concentrations within the culture, a binding technique utilizing antiprogesterone (antiP4) 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 anti-apoptotic properties of IGF-1 and estrogen by measuring the reduction of apoptosis in the embryos. Findings revealed that incubating for six days resulted in the greatest cell monolayer confluency. Results: The antiP4 effectively reduced progesterone levels in the culture of cumulus cells. Cleavage rates for embryos with and without progesterone absorption were recorded at 27.48% and 53.61%, respectively, while the rates of morula embryos increased from 5.73% to 27.59%. Additionally, the supplementation led to a decrease in 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.