Cooling prevents ischaemic testicular damage after spermatic cord clamping in rats

A controlled trial was conducted on four groups of seven rats to evaluate any beneficial effect of cooling to 15 degrees C on testicular ischaemia induced by clamping of the spermatic cord for 2, 4, 6 or 8 h. At operation the microscopic appearance of the testes on unclamping was a poor guide to ultimate viability, whereas by the third day macroscopic and microscopic appearances concurred. When killed on the third day, testicular histology demonstrated that increasing periods of clamping led to gross ischaemia and infarction when testes were maintained at 37 degrees C, and this was reduced greatly by testicular cooling. For each period of clamping, maintenance of spermatogenesis, expressed in terms of Johnsen's histological scores, was significant (P less than 0.01), being 2 (37 degrees C) vs 5.3 (15 degrees C) for 8-h clamping. It is proposed that testicular cooling should be used during autotransplantation of testes in humans.