Possible mechanisms for epididymal sparing during testicular ischemia

Objectives. Although extensive research has been conducted on the normal an atomy and physiology of the epididymis, the effects of ischemia on the orga n have not been primarily investigated. The aim of the present study war to investigate the macroscopic and microscopic effects of prolonged ischemia on the epididymis and the factors that may contribute to its resistance to ischemia, Methods. Six groups of male Sprague-Dawley rats (6 rats/group) were studied . Groups 1, 2, and 3 underwent a sham operation of 4, 8, and 12 hours, resp ectively, and groups 4, 5, and 6 underwent 4, 8, and 12 hours of ischemia, respectively. The ipsilateral testes and epididymides were monitored throug hout the experiment. At the conclusion of the experiment, bilateral orchiec tomy was performed, and structures were histologically evaluated. Results. There were no abnormal macroscopic findings of the bilateral epidi dymides of groups 1, 2, and 3 or of the contralateral, control epididymides of groups 4, 5, and 6. Macroscopically, there was a direct correlation bet ween the length of ischemia and the degree of hemorrhagic discoloration of the proximal caput. The degree of hemorrhagic infiltration noted microscopi cally was consistent with the macroscopic observations. The epithelia of th e ischemic epididymides remained intact with numerous microvilli. Conclusions. The results of this study suggest that the epithelium of the e pididymis is relatively resistant to ischemic damage compared with the gona d during testicular ischemia. (C) 1999, Elsevier Science Inc. All rights re served.