Changes in the Testis Interstitium of Rabbits from Birth to Sexual Maturity

Tae, Hyun Jin; Kim, In Shik

Abstract

Changes in the testis interstitium from birth to adulthood were studied in New Zealand white rabbits of 1, 7, 21, 35, 49, 70, 105, 147, 196, and 252 days (n=8 per group) of age. Testes of rabbits were fixed by whole body perfusion using a fixative containing 2.5% glutaraldehyde in cacodylate buffer, processed and embedded in Epon-araldite. Using 1 microm sections stained with methylene blueazure II, qualitative and quantitative (stereological) morphological studies were performed. Sperm production was measured by routine technique. The volume density of the interstitium represents 66.3% of the testicular parenchyma at day 1. Adult Leydig cells initially detected at day 7 (0.001%), increased progressively to reach a volume density of 2.6% by day 252. The absolute volume of mesenchymal cells, endothelial cells, pericytes, and myoid cells increased from birth to 252 days. The number of endothelial cells, pericytes, and myoid cells per testis increased gradually with age. The absolute numbers of adult Leydig cells and mesenchymal cells per testis increased linearly from birth to 252 days. The rate of production of adult Leydig cells was greater than that of mesenchymal cells in the postnatal rabbit testis through 252 days. The average volume of a mesenchymal cell increased from day 1 to day 70 and declined thereafter; the highest value was at day 70. Total sperm production and daily sperm production per testis increased significantly from 105 to 252 days of age. These results clarified the pattern of changes in the testis interstitium in rabbits from birth to adulthood and correlation these events with spermatogenesis.