Abundance of insulin-like growth factors 1 and 2, and type 1 insulin-like growth factor receptor in placentas of dogs

HERNÁNDEZ, ROCÍO; RODRÍGUEZ, FERNANDA M.; GAREIS, NATALIA C.; REY, FLORENCIA; BARBEITO, CLAUDIO G.; DIESSLER, MÓNICA E.

ANIMAL REPRODUCTION SCIENCE

ELSEVIER SCIENCE BV

Año: 2020 vol. 221

0378-4320

Insulin-like growth factors (IGFs) are among the primary compounds regulating placental development. In bitches, relative abundance of IGF1, IGF2 and IGFR1 mRNA transcripts have beenstudied in the pre-implantation uterus and early endotheliochorial placentas. The IGF2 andIGFR1 distribution has also been previously described in the uterus before embryo implantation.The aim of this study was to detect, characterize, and localize the presence of IGF1, IGF2, andIGFR1 in early-developing and mature placentas of dogs. Placentas of 15 bitches were analyzedusing immunohistochemistry. The IGFs were located in endometrial epithelium and glands, withthe staining pattern and intensity being less in mature placentas. Cytotrophoblast cells (CTB) andsyncytiotrophoblast (STB) cells contained both IGFs; the labeling was greater in CTB of the earlydeveloping than mature placentas. The maternal endothelium was positively stained for bothIGFs, while the vascular endothelium of the chorioallantoic membrane were only stained forIGF2. The IGFR1 was detected in all cell populations evaluated. Results regarding trophoblasticIGF are quite consistent with those reported in human placentas. Spatiotemporal IGFs/IGFR1pattern might reflect the occurrence of autocrine and paracrine signaling during placentation inbitches, and the involvement in early placental developmental processes. Furthermore, it is hypothesized that, besides hemotrophic actions of plasma IGFs, endometrial secreted IGFs maypromote early placental development through histotrophic signaling.