AbstractThe role of free radicals as mediators of ischemic injury to the testicle has been the subject of much investigation. We studied whether the testicular damage induced in the rat by cadmium chloride (CdCl 2 ) can be prevented by administration of free-radical scavengers.Sprague-Dawley rats (n = 45) were divided into 9 groups as follows: a negative control group; two positive control groups, one of which received injection of 1 mg/kg body weight of CdCl 2 and the other 4 mg/kg body weight; and six cotreatment groups, each of which underwent one of these three procedures but was concurrently treated with heparin, oxypurinol, or superoxide dismutase (SOD). The damage was assessed by measurement of testicular weight, lactate dehydrogenase-X (LDH-X) activity, and histology.Testicular weight decreased significantly in the positive control groups (P <0.05) compared to the negative control group, whereas testicular weight in oxypurinol or SOD cotreatment groups did not decrease significantly with the exception of those rats given the higher dose of CdCl 2 . The results were similar with regard to testicular LDH-X activity and histology.These findings suggest that CdCl 2 induces impairment of testicular function and causes a marked reduction in testicular LDH-X activity; that LDH-X activity is a biological marker of testicular damage; and that, except at high doses of CdCl 2 , this damage can be prevented by oxypurinol or SOD.