Early development and putative primordial germ cells characterization in dogs

Area of Science:

• Reproductive Biology
• Developmental Biology
• Comparative Embryology

Background:

• Primordial germ cells (PGCs) are crucial for reproduction.
• Distinct PGC populations (gonocytes, intermediate cells, pre-spermatogonia) have been identified in human fetal testes.
• These PGC populations have not been previously studied in canine embryos.

Purpose of the Study:

• To identify and characterize PGC populations in canine embryos.
• To compare canine PGCs with those found in human fetal testes.
• To evaluate the utility of anti-human OCT-4 antibody for canine PGC identification.

Main Methods:

• Development of a canine embryo isolation protocol.
• Isolation of 15 canine embryos (21-25 days gestation) via ovary hysterectomy.
• Histological analysis and immunostaining with anti-human OCT-4 antibody.

Main Results:

• Two distinct PGC populations were identified in canine embryos between 21-25 days gestation.
• Population 1 exhibited gonocyte morphology; Population 2 showed typical PGC features.
• Both populations stained positively for OCT-4, with differential expression observed by day 25.

Conclusions:

• Canine embryos harbor two PGC populations morphologically similar to human gonocytes and intermediate cells.
• Anti-human OCT-4 antibody is a viable marker for identifying canine PGCs.
• Pre-spermatogonia are anticipated in later stages of canine fetal development.