Evaluation of cadmium toxicity and its association with iron on the gonads of female rats

Abstract

Cadmium has been identified as one of the endocrine-disrupting chemicals. Several studies on heavy metals focus on individual metals neglecting the fact that they occur in association with other metals in the environment, a situation that can affect the toxic capacity of each metal. The current study was therefore designed to examine the possible influence of iron (Fe) on cadmium (Cd) toxicity in the gonad of female rats. Twenty adult female albino rats used in this study were divided into four groups. The groups were designated as group A-control (rats administered Cd-free water), group B rats were exposed to Cd-tainted water, group C rats were exposed to Fe-tainted water and group D rats were exposed to combined Cd+Fe tainted water. The treatments were done daily for four weeks. At the end of 4 weeks of exposure, there was significant increase in ovary CAT activity of rats exposed to Cd+Fe when compared to the control. The malondialdehyde (MDA) level in ovary of rats exposed to Fe only was significantly increased (p≤0.05) relative to the control. Similarly, there was a significant increase in serum cholesterol level of rats exposed to Cd+Fe simultaneously when compared to the Cd only and Fe only treated groups. The levels of Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH) were significantly increased (p≤0.05) in sera of rats exposed to Cd only, Fe only and Cd+Fe when compared to the control. The levels of estradiol were significantly decreased in all the treated groups relative to control. The level of testosterone was significantly increased (p≤0.05) in Cd+Fe group relative to the control. Histological study revealed atretic and disintegrating follicles in ovary of rats exposed to Cd only and combined Cd+Fe. The results from this study suggest that cadmium only as well as combined cadmium and iron are responsible for the biochemical changes induced in the ovary. The presence of Cd caused oxidative stress in the ovary and an imbalance in serum levels of the reproductive hormones analyzed. Since Cd only was able to cause the changes observed and similar changes was also observed in presence of iron, it can therefore be suggested that Cd is responsible for the changes since iron was unable to ameliorate its effect. Findings from histological examination of the ovaries that there was profound disintegration with follicular damage appear to corroborate the biochemical observation made in this study. In conclusion, it appears that cadmium in the presence of iron can still exhibit its gonadal toxicity without antagonism or synergism with iron as shown in the rats exposed via water.