The Nephroprotective Effects of Graded Concentrations of Calcium and Magnesium on Nephrotoxicities Induced by a Constant Toxic Concentration of Cadmium and Lead in Rats

Abstract

Aims: To concurrently administer constant toxic concentrations of Cd and Pb with graded concentrations of Ca and Mg using a rat model to determine their nephroprotective effects against Cd and Pb nephrotixicities. Study Design: Wistar rats were divided into five groups of four rats per group in metabolic cages. Group one was placed on tap water only, while group two to five were placed on a constant concentration of 0.327 mg/L lead and 0.079 mg/L cadmium concurrently with graded magnesium and calcium. Place and Duration of Study: The animal House of Pharmacology Department, Anatomy and Biochemistry laboratories, University of Jos, Nigeria, were used for treatments, histochemical and biochemical analyses respectively, between December 2013 and April 2014. Methodology: Their feed was mashed with the same water meant for each group. All the groups fed and freely drank from the water for a period of fourteen (14) days. Twenty-four hour (24h) urine samples were collected from the rats at their respective groups in the urine collector of the metabolic cages for fourteen days. The urine samples were kept frozen until needed for clinical analysis. At the termination of the experiments, the rats were humanely sacrificed, the kidneys identified and fixed in 10% formal saline for histopathological studies. Results: Kidney biomarkers in urine decreased, while urinary excretion of urea and creatinine increased as the concentrations of calcium and magnesium were elevated. The histopathological analyses show that there was no significant difference (P<0.05) between control and groups 4 and 5, but there was significant difference (P>0.05) between control and groups 2 and 3. Conclusion: Results suggest that calcium and magnesium could mitigate the nephrotoxicities induced by cadmium and lead. Therefore, good proportion of calcium and magnesium in the diet and water would enhance good health especially for those living in environments contaminated with heavy metals.