Tolerance of rat testis to graded periods of total circulatory isolation.

Infertility because of testicular damage is a distressing problem for survivors of cancer chemotherapy. We have previously described a cytoprotective effect of temporary testicular circulatory isolation (TCI) during doxorubicin administration in the rat. In this report we define the relationship between duration of TCI and testicular ischemic injury, using paired groups of animals with normothermic TCI and hypothermic TCI. Sixty rats were used and received TCI for varying lengths of time up to 180 minutes, with or without hypothermia. On day 56 +/- 4, all rats were killed and necropsied. Testicular injury was evaluated qualitatively by histology and quantitatively by testicular weight, sperm head count, repopulation index, and epididymal index. Warm TCI for up to 60 minutes induced modest damage to germ cells, while injury was greater with cold TCI. Leydig cells and vascular tissues were essentially unaffected by TCI, although Sertoli cell abnormalities were noted in rats receiving a long duration of TCI.