Histological and Histomorphometric Changes of the Rabbit Testis During Postnatal Development

摘要

The aim of the current study was to follow up the histological and histomorphometrical changes of descending rabbit testis during different postnatal-developmental stages (1-day and 1-4-, 8-, 12-, 16-, 20- and 24-weeks). The testes were found at the sublumbar region just after birth, moved into the inguinal canal after 4 weeks, located near the scrotum after 8 weeks and were completely within the scrotum after 12-16 weeks. Paraffin and semi-thin sections were taken from the testis and examined with light microscopy. The testis was surrounded by a fibrous capsule with no smooth muscle fibers until 12 weeks, but smooth muscle fibers were seen after 16 weeks. Testicular parenchyma was made up of solid seminiferous cords with no lumina and the cords had only 2 types of cells; gonocytes and Sertoli cells until 8 weeks. Lumination of the testicular cords started after 12 weeks forming seminiferous tubules. Seminiferous tubules were lined by spermatogonia, spermatocytes and round spermatids, in addition to Sertoli cells. After 16-24 weeks, spermatogenesis was very active and sperms were seen. Leydig cells were small and less active at 1-day postnatal but became large and more active after 16-24 weeks. Many growth parameters of seminiferous cords or tubules including their diameter and the numbers of germ cells and Sertoli cells were recorded. The current study widely covered different points of rabbit?s testicular maturity including the anatomical location and the histological and histomorphometrical changes of descending rabbit testis.