Prenatal development of the intramural vascular system of the uterine tube in the European shorthair cat.

CONTEXT: Early vascular development during the prenatal period is essential for the proper formation of all organs, including the reproductive system.

AIMS: This study aimed to characterize the development of the intramural vascular system in the domestic cat's uterine tube, with emphasis on changes associated with wall layer formation.

METHODS

Uterine tubes from 38 domestic cat fetuses (36-63 days post-conception) were examined using light microscopy, vascular corrosion casts, and scanning electron microscopy.

KEY

RESULTS

In early stages, the vascular system of the rudimentary paramesonephric duct (uPD) is simple, comprising longitudinal vessels and a superficial vascular network. Initially, all vessels resemble capillaries. By Days 42-43 post-conception, vascular differentiation into arterioles and venules becomes evident, progressing to arteries and veins with distinct surface relief visible on corrosion casts by late gestation. Approximately by Day 50 post-conception, as the layers develop in the uterine tube wall, a subepithelial capillary network emerges, connecting with the superficial vascular system. At term, the uterine artery becomes tortuous and branches above the isthmus; veins accompany the arteries. The mature intramural vascular system includes circumferential arteries and veins, as well as subepithelial and subserosal capillary networks.

CONCLUSIONS

A basic vascular architecture supporting tissue growth develops prenatally, laying the foundation for postnatal expansion linked to mucosal and muscular layer maturation.

IMPLICATIONS: This first-time analysis of feline uterine tube prenatal angioarchitecture provides novel insights into reproductive system histogenesis in a species both common in human environments and important in veterinary science.