Light and electron microscopic study of seminiferous tubule in the unilateral undescended testis

Park, Do Young; Kim, Chul Sung

Abstract

The present study was performed to determine the optimal time for orchiopexy and seek further understanding of the pathophysiology of infertility as a complication of unilateral cryptorchidism. Testicular tissues for light and electron microscopic examination were biopsied from not only cryptorchid but also contralateral scrotal testes of 28 patients with unilateral cryptorchidism, aged 1 to 24 years. The most considerable findings were as follows; 1. Mean tubular diameter of cryptorchid and contralateral scrotal testes was markedly increased from the age of 13 years. The mean tubular diameter of cryptorchid testes was shorter than that of contralateral scrotal testes. 2. Average cell population in tubule of cryptorchid testes remained at low level compared to contralateral scrotal testes, especially a marked decrease after the age of 13 years. Mean spermatogonia count per tubule of cryptorchid testes was lower than that of contralateral scrotal testes. During the puberty, mean spermatogonia count per tubule of scrotal testes was higher than that of cryptorchid testes and this difference was statistically significant (p<0.05). 3. Basement membrane of both cryptorchid and contralateral scrotal testes became markedly thickened from the age of 13 years and basement membrane of cryptorchid testes was thicker than that of scrotal testes. 4. As the pattern of spermatogenesis, the cryptorchid testes showed germ cell hypoplasia and scrotal testes showed incomplete spermatogenic arrest from the age of 13 years. 5. Leydig cell in interstitium was observed in both cryptorchid and contralateral scrotal testes from the age of 13 years and the number of Leydig cell in the cryptorchid testes was lower than that in the scrotal testes. 6. In ultrastructural study, the decrease in number of mitochondria and ribosomes of rough endoplasmic reliculum of the germ cell and Sertoli cell of cryptorchid testes became evident primarily after 5 years of life compared to those of contralateral scrotal testes. In conclusion, the implications of above finding was to urge surgical correction of unilateral cryptorchid testes before 5 years of life.