Effects of chronic mercury exposure on the rat kidney cortex a studied morphometrically by light and electron microscopy

Amelioration of mercuric chloride-induced physiologic and histopathologic alterations in rats using vitamin E and zinc chloride supplement

The drastic effects of mercuric chloride and the protective efficiency of vitamin E and zinc chloride co-supplementation were clearly investigated in this study. Male rats were divided into four groups. The first was the control. The second received vitamin E (100 mg/kg) and zinc chloride (30 mg/kg) daily. In comparison, the third received mercuric chloride (1 mg/kg) daily, and the fourth received the same mercuric chloride dose supplemented with the same vitamin E and zinc chloride doses. Mercury promotes a significant decline in body weight. It causes a considerable reduction in total red blood cells (RBCs) count and hemoglobin concentration; however, white blood cells (WBCs) increased significantly. Significant mercury-induced elevations in hepatic and renal functions were observed. Mercury induced substantial reductions in catalase (CAT) and superoxide dismutase (SOD). Mercury caused apoptotic DNA fragmentation. It induced degeneration and necrosis in the liver and kidney. It induced necrosis, leukocyte infiltration and blood vessel congestion in the cerebral cortex. Shrinkage and deterioration of Purkinje cells of the cerebellum were observed in response to mercuric chloride toxicity. Mercuric chloride enhanced shrinking in seminiferous tubules and Leydig cells. It reduced sperm count, sperm motility, and testosterone concentration; however, it promoted abnormal sperm morphology. Administration of vitamin E and zinc chloride showed marked improvement in different parameters under investigation, however, further research is needed to determine fate of mercury.

Uriniferous tubule: structural and functional organization

The uriniferous tubule is divided into the proximal tubule, the intermediate (thin) tubule, the distal tubule and the collecting duct. The present chapter is based on the chapters by Maunsbach and Christensen on the proximal tubule, and by Kaissling and Kriz on the distal tubule and collecting duct in the 1992 edition of the Handbook of Physiology, Renal Physiology. It describes the fine structure (light and electron microscopy) of the entire mammalian uriniferous tubule, mainly in rats, mice, and rabbits. The structural data are complemented by recent data on the location of the major transport- and transport-regulating proteins, revealed by morphological means(immunohistochemistry, immunofluorescence, and/or mRNA in situ hybridization). The structural differences along the uriniferous tubule strictly coincide with the distribution of the major luminal and basolateral transport proteins and receptors and both together provide the basis for the subdivision of the uriniferous tubule into functional subunits. Data on structural adaptation to defined functional changes in vivo and to genetical alterations of specified proteins involved in transepithelial transport importantly deepen our comprehension of the correlation of structure and function in the kidney, of the role of each segment or cell type in the overall renal function,and our understanding of renal pathophysiology.

Mercury chloride increases hepatic alanine aminotransferase and glucose 6-phosphatase activities in newborn rats in vivo

This work investigated the in vivo and in vitro effects of HgCl2 and ZnCl2 on metabolic enzymes from tissues of young rats to verify whether the physiological and biochemical alterations induced by mercury and prevented by zinc are related to hepatic and renal glucose metabolism. Wistar rats received (subcutaneous) saline or ZnCl2 (27 mg/kg/day) from 3 to 7 days old and saline or HgCl2 (5.0 mg/kg/day) from 8 to 12 days old. Mercury exposure increased the hepatic alanine aminotransferase (∼6-fold) and glucose 6-phosphatase (75%) activity; zinc pre-exposure prevented totally and partially these mercury alterations respectively. In vitro, HgCl2 inhibited the serum (22%, 10 μM) and liver (54%, 100 μM) alanine aminotransferase, serum (53%) and liver (64%) lactate dehydrogenase (10 μM), and liver (53%) and kidney (41%) glucose 6-phosphatase (100 μM) from 10- to 13-day-old rats. The results show that mercury induces distinct alterations in these enzymes when tested in vivo or in vitro as well as when different sources were used. The increase of both hepatic alanine aminotransferase and glucose 6-phosphatase activity suggests that the mercury-exposed rats have increased gluconeogenic activity in the liver. Zinc prevents the in vivo effects on metabolic changes induced by mercury.

Serum selenium and glutathione-peroxidase activities and their interaction with toxic metals in dialysis and renal transplantation patients

Selenium, aluminum, cadmium, and magnesium concentrations and glutathione-peroxidase activities in sera of 35 healthy individuals, 30 renal transplants, and 30 hemodialysis patients were measured. Serum selenium, aluminum, and cadmium concentrations in both groups of patients were higher than the controls (p less than 0.001), whereas the serum glutathione-peroxidase levels were lower (p less than 0.001). According to our results, it can be concluded that the patients receiving hemodialysis are subjected to more toxic elements than the transplantation patients. These findings imply that dietary selenium supplement may be suggested in renal failure for the detoxification of elements, such as cadmium and mercury. The essential trace element selenium takes part not only in the direct protection of endothelial cells against the accumulation of aggressive oxygen species, but also in the prevention of the toxic effects of cadmium or in the modulation of the active calcium transport.

Influence of a standard laboratory diet containing nutritionally adequate levels of selenium on renal pathology from mercury released by experimental amalgam tattoos

Twenty-four guinea pigs were subcutaneously implanted with 2 X 25 mg of powdered dental amalgam for between 1 and 24 months. Four animals served as controls. All animals were fed a standard diet containing 0.2 microgram/g selenium (Se). Mercury (Hg) was released from the implants at an average rate of 21.7 micrograms/d and 4.35-16.94 micrograms of Se were consumed daily in the diet. The renal Hg rose to a maximum of 263 micrograms/g at 11 months in implanted animals and 6.65 mg Hg was excreted over 2 yr. The renal proximal tubular cells of implanted animals contained visible Hg deposits in secondary lysosomes and within nuclei containing both Hg and Se. No other signs of obvious renal pathology were seen in implanted animals as compared with controls. It would seem likely that the low Se levels present within this standard laboratory diet were sufficient to protect against Hg toxicity.

Early effects of gentamicin, tobramycin, and amikacin on the human kidney

The early alterations at the level of the proximal tubule of the human kidney caused by the three most currently used aminoglycosides, gentamicin, tobramycin, and amikacin, were studied. A prospective, randomized, and comparative approach using multidisciplinary methods was used. The patients received either no treatment or one of the three aminoglycosides at a therapeutic dose for 4 days preceding nephrectomy for neoplasia partly involving one kidney. The three aminoglycosides studied induce an early lysosomal phospholipidosis. Gentamicin and tobramycin cannot be distinguished on the basis of drug tissue accumulation, lysosomal overloading, or effect on lysosomal phospholipase A1. Amikacin induces significantly lower lysosomal overloading and no loss of phospholipase A1 activity.