HISTOMORPHOMETRIC STUDY ON GERM-CELL DIFFERENTIATION OF UNILATERAL CRYPTORCHIDISM IN THE IMMATURE PIG

Early spermatogenesis from gonocytes to A-type spermatogonia is inhibi ted in boys with cryptorchidism. Histological lesions in the undescend ed testes (UDT) are presumably secondary to the extrascrotal position. The purpose of this study is to determine the abnormalities in number and maturation of germ cells in pigs with undescended testes and to e xamine the effect of UDT location on early germ cell differentiation. Testicular biopsies from 4-week-old pigs with natural unilateral crypt orchidism (n = 20) were divided into three groups: (1) intraabdominal testes, (2) superficial inguinal pouch testes, and (3) contralateral d escended testes (CDT). The testis weight (P < .01) and the area of cir cular cross-section of the seminiferous tubules (P < .05) in intraabdo minal testes was lower than in CDT. The number of germ cells (per tubu lar cross-section) (P < .05) and A-type spermatogonia (P < .05) in int raabdominal and inguinal testes was significantly lower than in CDT. I n contrast, the number of gonocytes in intraabdominal testes was simil ar to that in CDT. The number of Sertoli cells was similar in the thre e groups. These results demonstrate that defective transformation of g onocytes to A-type spermatogonia in pigs is similar to that observed i n boys with unilateral cryptorchidism, The different locations of UDT in the pig are correlated with the degree of impaired spermatogenesis. Copyright (C) 1996 by W.B. Saunders Company