Revealing the cytokine-mediated embryo-maternal crosstalk during extended in vitro culture in the Arabian camel (Camelus dromedarius).

Abstract

This study reports, for the first time, the establishment of endometrial organoids (EOs) from the Arabian camel (Camelus dromedarius) and evaluates their suitability as an in vitro model for embryo-maternal interactions during implantation. Endometrial tissues were collected from non-pregnant she-camels and cultured in Matrigel with a defined growth medium. By Day 7, organoids displayed a spherical morphology (200-250 µm), remained viable for up to 20 days, and expanded to approximately 1 mm. They exhibited epithelial characteristics and high proliferative activity, confirmed by expression of mucin-1, pan-cytokeratin, vimentin, and Ki67. Day 7 in vitro-produced embryos co-cultured with EOs showed significant improvements in development and trophoblast outgrowth. This was accompanied by upregulation of key developmental genes (OCT4, c-MYC, KLF4, CDX2). Cytokine profiling revealed enhanced bidirectional signaling: embryos increased secretion of CCL2, CCL4, IGF-1, IFNG, IL1α, IL12b, IL-8, LIF, IL-10, and NTF3, while EOs upregulated VEGFA, IL-8, CCL2, and TIMP1. Co-culture uniquely induced additional cytokines and amplified signaling intensity. Metabolomic analysis of embryo-conditioned medium identified 108 metabolites, including steroids associated with immunomodulation. Notably, embryos cultured in EO-conditioned medium developed up to Day 21 post-cleavage, reaching a mean diameter of 2.4 mm. Overall, camel EOs provide a physiologically relevant platform that supports embryo development and enables detailed investigation of cytokine-mediated embryo-maternal communication and implantation processes in the dromedary camel.