Morphological Signs of a Direct Effect of Experimental Cryptorchidism on the Sertoli Cells in Rats Irradiated as Fetuses

The present study investigated the morphological effects of experimental cryptorchidism on testes lacking germinal cells. For this purpose male fetuses were irradiated in utero with a dose of 150 rad. This procedure damages the gonocytes and results in testes almost devoid of germinal cells. At birth, distal unilateral gubernaculotomy was performed to induce unilateral cryptorchidism. The testes of 20-day-old rats (just after testicular descent) and 30-day-old rats were fixed by arterial perfusion, and testicular morphology was investigated by light and electron microscopy. Differences between abdominal and scrotal testes were quantified using morphometric methods. At 20 days of age an accumulation of lipid droplets was noticed in the Sertoli cells in abdominal testes. Apart from this no morphological differences were noticed between abdominal and scrotal testes. At 30 days of age the total Sertoli cell mass per testis and the average Sertoli cell size were reduced in abdominal testes, but the total number of Sertoli cells per testis was unaffected. A lumen was noticed in 72% of the tubular cross sections in abdominal testes and in 32% of the scrotal ones. The cytoplasm of Sertoli cells in abdominal testes contained considerably more empty looking vacuoles and lipid droplets than did Sertoli cells in scrotal testes. Leydig cell morphology was also similar in scrotal and abdominal testes at this age. The results indicate that there is a direct and early effect of experimental cryptorchidism on Sertoli cell structure.