Mechanisms of Zinc, Cysteine and Selenium Protection Against Cadmium-Induced Vascular Injury to Mouse Testis

Abstract

It is known that the selective injurious effect of cadmium on the testis can be prevented by zinc, cysteine or selenium. Studies, conducted in CD-1 mice, were initiated to determine whether any of these treatments offered protection by preventing cadmium from reaching the testis in doses sufficient to cause injury. Using cadmium chloride, labelled with 109Cd, it was shown that none of these protective agents decreased the amount of cadmium reaching the testis. Zinc acetate evoked no significant changes, cysteine brought about a slight enhancement of cadmium level but selenium dioxide produced a marked and prolonged elevation of cadmium uptake by the testis. Comparable studies in which selenium, rather than cadmium, was labelled (75Se) demonstrated that, in the presence of cadmium, selenium levels were augmented. Possible mechanisms are discussed to explain the diverse means of protection offered by zinc, cysteine and selenium. Since the site of cadmium-induced testicular injury has been pinpointed at its vasculature, it is suggested that these protective agents exert their action at the vascular level.

Early Actions of Cadmium in the Rat and Domestic Fowl Testis

“…The uptake pattern, following s.c. injection, in the domestic fowl testis, muscle and liver is very similar to that found in the rat in this study and to that previously reported in the rat by Johnson & Miller (1970). The relative distribution in these tissues in general is in harmony with previous work for later sampling times in the rat (Decker, Byerrum & Hoppert, 1957;Friberg & Odeblad, 1957), mouse (Cotzias, Borg & Selleck, 1961a;Berlin & Ullberg, 1963;Gunn, Gould & Anderson, 1968), dog (Walsh & Burch, 1959), goat (Miller, Blackmon & Martin, 1968) and calf (Powell, Miller, Morton & Clifton, 1964 (Gunn et al, 1968), while Zn decreased Cd uptake by testes. At first (Text- fig.…”

Environmental Impact of Cadmium: A Review by the Panel on Hazardous Trace Substances

“…Studies by Parizek (169) first established the extraordinary protective effect of zinc treatment against the acute atrophy of the testis resulting from cadmium injections. This has also been studied by Gunn and his coworkers (170). Cysteine and selenium also will protect against the cadmium testicular atrophy.…”

“…The subjects were reported to have ingested an average of 170 jug Cd/day from the diet and to have excreted about 42 pg/day in the feces and 94 jug/day in the urine. Friberg et al (30) point out that these results indicated an absorption of 75%o of the intake, much higher than reported by others.…”

Isolation and Characterization of Cadmium-Binding Protein From Rat Testes

“…Gunn, Gould & Anderson (1968) have suggested that the specific site where cadmium produces acute testicular injury is the vascular endothelium. Webb (1972) studied the biochemical effects of cadmium injury on mouse and rat testis with regard to the competitive antagonism between Cd2+ and Zn2+ and has shown that the antagonism occurs in the epididymis.…”