Effects of external inguinoscrotal compression on descent of the testis in rats

Intrauterine compression of the developing genitalia by the feet in early fetal development may be a cause of delayed descent of the testes. The purpose of our experiments on neonatal rats was to determine whether compression on the inguinoscrotum would impair testicular descent, which normally occurs during the 1st postnatal month. Two methods of compressing the inguinoscrotal region on one side were used: firstly, a ribcage graft from an inbred littermate was inserted subcutaneously in one series, and secondly, skin tightening was created by excising a wide area superficial to the gubernaculum and stitching the skin edges together longitudinally. Descent of the testis was retarded on the compressed side compared with both the non-compressed side and the sham-operated animals. The testes that had retardation of descent were smaller than those of the opposite side and of the sham-operated rats. It was concluded that experimental compression in rats may be akin to focal intrauterine compression in the human, causing delayed descent and changes in dimensions of the testes.This work was supported by grants from the National Health and Medical Research Council (Australia) and the Royal Children's Hospital Research FoundationOffprint requests to: F. D. Stephens