[Preventive effect of selenium against the testicular injury by cadmium]

An experimental study was performed on orchiopathy (testis disorder) by using cadmium (Cd) and on the prevention of orchiopathy by the administration of selenium (Se). By a single administration of Cd 1.4 mg/kg (12.4 mumol/kg) or a second administration of Cd 1.4 mg/kg 24 hr after the administration of Cd 1.0 mg/kg (8.9 mumol/kg), the testis of a mouse showed ex-tensive necrosis, and an extreme decrease of glutathione (GSH) concentration accompanied by an increase of thiobarbituric acid reactive substances (TBARS). When Se 1.4 mg/kg (17.7 mumol/kg) was given at the same time as Cd 1.0 mg/kg, the disorder was completely prevented and their serum Cd and Se concentrations were 1165 +/- 268 ng/ml and 534 +/- 128 ng/ml, respectively. However, when Se was given, separately from the Cd administration, either 24 hr or 72 hr before Cd administration, no effect to prevent testis disorder was found. On the other hand, when Se 1.4 mg/kg and Cd 1.0 mg/kg were given simultaneously and then Cd 1.4 mg/kg was administered 24 hr and 72 hr after the simultaneous injection, respectively, there was no sign of disorder caused by the second administration of Cd. When Cd was given after administration of Cd and Se, Cd concentration in the testis (0.88 +/- 0.078 microgram/g and 0.77 +/- 0.03 microgram/g) was about twice as much as the concentration in the case of no administration of Se (0.30 +/- 0.04 microgram/g). The testicular dysfunction could not be explained by the increased Cd concentration in the testis. The groups with high Cd concentration in the testis were accompanied by an increase in metallothionein (92.8 +/- 18.6 micrograms/g and 92.5 +/- 7.3 micrograms/g), but these did not exceed the level of the control group (94.5 +/- 8.4 micrograms/g) which had neither Cd nor Se injections. In the groups with testicular necrosis, concentrations of zinc (Zn) and magnesium (Mg) were decreased while an increase in concentrations of calcium (Ca) and iron (Fe) was observed. These results suggest that Se concentration must be maintained to prevent the testicular disorder caused by Cd.