Anim Rep od. 2025; 22(3)
THEMATIC SECTION: 41ST ANNUAL SCIENTIFIC MEETING OF THE ASSOCIATION OF EMBRYO TECHNOLOGY IN EUROPE (AETE)
EMBRYOLOGY AND DEVELOPMENTAL BIOLOGY
Bo ine emb yonic disc cha ac e isa ion in in i o-
p oduced (IVP) emb yos a ea ly de elopmen al s ages
Sa a Núñez To isco1, T udee Fai 1, Pa Lone gan1
1Uni e si y College Dublin, I eland
E-mail: [email p o ec ed]
P egnancy loss in ca le du ing he i s imes e is p ima ily associa ed wi h impai men s in blas ocys
de elopmen and concep us elonga ion and a achmen . Addi ionally, e idence sugges s ha he me hod used
o p oduce he emb yo can al e endome ial esponses by modi ying bo h he endome ial ansc ip ome
and emb yonic gene exp ession. Howe e , li le is known abou he pheno ypic al e a ions ha may a ise
om he o igin o he emb yo. The e o e, his s udy aims o pheno ypically cha ac e ize bo ine in i o
p oduced (IVP) emb yos a ea ly de elopmen al s ages, ocusing on emb yonic disc p og ession du ing he
p ocess o blas ocys expansion and ha ching. Bo ine blas ocys s we e p oduced om aba oi -de i ed
o a ies om mul iple collec ion days using comme cial media o in i o ma u a ion, e ilisa ion and cul u e
(S oebech Media, ARTSMedia Denma k ApS). Mean blas ocys a e om s a ing cumulus-oocy e-complexes
a ied om 35 o 45%.The exp ession o SOX2 and SOX17, es ablished bioma ke s o inne cell mass (ICM)/
epiblas and hypoblas cells, espec i ely, was e alua ed in IVP blas ocys s a days 7 (D7, blas ocys s, n=7), 8
(D8, ha ched blas ocys s, n=4), and 9 (D9, ha ched blas ocys s, n=6), using wholemoun immuno luo escen
labelling. Iso ype-ma ched IgG nega i e con ols we e included o each bioma ke . Z-s acks we e acqui ed
using an LSM800 Ai yscan con ocal mic oscope and analysed wi h Fiji (Schindelin, e al., Na u e Me hods,
9(7), 676–682, 2012). S a is ical analyses (one-way ANOVA ollowed by Tukey’s HSD es ) we e pe o med in
R. Signi icance was de ined a P<0.05. The numbe o SOX2+ cells dec eased signi ican ly ac oss ime. F om
D7 (52.4%, 33/63) o D8 (28.3%, 56/198), he e was a 24.1% educ ion, ollowed by a u he 16.8% dec ease
om D8 o D9 (11.5%, 24/209), esul ing in a o al educ ion o 40.9% om D7 o D9. This educ ion coincides
wi h he de elopmen al ansi ion om he blas ocys s age o blas ocys expansion and ha ching om
he zona pellucida, du ing which he ICM begins o di e en ia e in o epiblas and hypoblas lineages, wi h
SOX2 becoming speci ic o epiblas cells. SOX17 exp ession was de ec ed in D8 blas ocys s and appea ed
o co-localise wi h SOX2. Addi ionally, by D9, 66.7% p esen ed SOX17 labelling in cells di ec ly unde nea h
SOX2+ cells and in cells mig a ing owa ds he blas ocoel, po en ially indica ing he ini ia ion o hypoblas
mig a ion. Con inued in es iga ion is ongoing o ully cha ac e ize hese de elopmen al changes as he
emb yo p og esses h ough o oid, ubula and ilamen ous s ages and o de e mine whe he , and how, he
o igin o he emb yo (in i o de i ed s. IVP) con ibu es o pheno ypic a ia ion du ing ea ly de elopmen
ha may unde lie emb yonic loss.
Acknowledgmen s: This esea ch was unded by AFRODITA ha has ecei ed unding om he Eu opean
Union’s Ho izon Eu ope p og amme unde he MSCA Doc o al Ne wo k g an ag eemen No 101120126.
Keywo ds: bo ine, emb yonic disc, IVP.
