カドミウムによる精巣障害に対するセレニウムの防御

抄録

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 1.4mg/kg (12.4μmol/kg) or a second administration of Cd 1.4mg/kg 24hr after the administration of Cd 1.0mg/kg (8.9μmol/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 1.4mg/kg (17.7μmol/kg) was given at the same time as Cd 1.0mg/kg, the disorder was completely prevented and their serum Cd and Se concentrations were 1165±268ng/ml and 534±128ng/ml, respectively. However, when Se was given, separately from the Cd administration, either 24hr or 72hr before Cd administration, no effect to prevent testis disorder was found. On the other hand, when Se 1.4mg/kg and Cd 1.0mg/kg were given simultaneously and then Cd 1.4mg/kg was administered 24hr and 72hr 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±0.078μg/g and 0.77±0.03μg/g) was about twice as much as the concentration inthe case of no administration of Se (0.30±0.04μg/g). The tes-ticular dysfunction could not be explained by the increased Cd concentration in the testis. The groups with high Cd concent-ration in the testis were accompanied by an increase in metallothionein (92.8±18.6μg/g and 92.5±7.3μg/g), but these did notexceed the level of the control group (94.5±8.4μg/g) which hadneither 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) andiron (Fe) was observed. These results suggest that Se concent-ration must be maintained to prevent the testicular disorder caused by Cd.