Effects of dietary cadmium exposure on osmoregulation and urine concentration mechanisms of the semi-desert rodent Meriones shawi

Abstract

Contamination by cadmium in the environment is of great concern because of its toxicity and threats to human and animal health. The current study was conducted to investigate the effects of a cadmium contaminated diet on the osmoregulation and urine concentration mechanisms of the semi-desert rodent Meriones shawi and eventual accumulation of this metal in vital organs such as the kidneys, which are directly implicated in water regulation. Originally, we used Differential Pulse Anodic Stripping Voltammetry (DPASV) to avoid the matrix interference due to the highly organic content in the biological samples. Our results show that Meriones shawi successfully maintained a homeostasis state and presented a special adaptation to regulate urine volume during cadmium exposure by decreasing diuresis and increasing urinary osmolality. The plasma osmolality and hematocrit remained constant throughout the experiment. The stripping signals of cadmium are linear up to 0.3-100 μg L(-1) range, with a detection limit of 0.28 μg L(-1). The DPASV technique was useful for easy, fast, selective and sensitive determination of Cd, which permits working at cellular concentration. This gives us more information about the chemical form in which Cd is introduced into the organ, as well as the intracellular Cd quantities. This study has potential importance if this valuable novel animal model, imitating human and animal environmental chronic exposure to Cd, could serve as an appropriate terrestrial biomonitor for Cd contaminated sites. These results are encouraging in the context of developing a low-cost and fast technology for the detection of pollutants and for studying the impairment caused by their effects.

Effect of Cadmium Contaminated Diet in Controlling Water Behavior by Meriones shawi

“…Although changes in body mass in Cd-exposed animals are assumed to be due to reduction of daily consumption of food, this decrease of food uptake became larger in animals both deprived water and treated with Cd. This is in agreement with the findings of Pettersen et al [41] who demonstrated that rats exposed to Cd become anorexic. An important finding in this study, described by other authors Woltowski et al [42] and Leffel et al [43] was the early occurrence of Cd induced hepatic damage manifested by lower liver weight, which was explained by the high level of Cd found in livers of exposed animals.…”

Peculiarities of water-electrolytic metabolism of rats with “slow” type of acetylation after a combined effect of cadmium chloride and sodium nitrate

“…We observed 24.2 % increase of sodium ions concentration in the urine, and 1.2 times increase -blood/urine ratio concentrations without clearance changes of this electrolyte. Contrary to the conclusions suggested by the authors [14], increased urine concentration should not be considered as the reaction to maintain waterelectrolytic state. Under conditions of cadmium effect kidneys are the most susceptible organ.…”

“…It should be noted that in other experimental studies of osmoregulation mechanisms under conditions of cadmium-containing diet without consideration of acetylation type plasma osmolality did not change, although urine osmolality increased and diuresis decreased [14]. We observed 24.2 % increase of sodium ions concentration in the urine, and 1.2 times increase -blood/urine ratio concentrations without clearance changes of this electrolyte.…”

Protective Effects of Selenium on Hepatotoxicity Caused by Subacute Experimental Combined Exposure to Cadmium and Lead in Rats

“…It has been demonstrated that cadmium chloride in solutions is aversive to rats and the decrease in drinking water intake occurs rapidly, so the physiological impairment could be excluded as a cause [14]. Another study concluded that Meriones shawi rodents maintained a homeostasis state and presented an adaptation to regulate volume during cadmium exposure by decreasing diuresis and increasing urine osmolality [35]. It is generally known that fluid intake decreases with the increase in the osmolarity of the drinking water, so another less plausible cause for the difference in water consumption among groups in this study could be the increase in the osmolarity of the drinking water.…”