Collate literature data on toxicity of Chromium (Cr) and Nickel (Ni) in experimental animals and humans

Abstract

Literature data on Chromium show that trivalent chromium has low acute and long term toxicity whilst hexavalent chromium is acutely toxic and produces long term effects on hematological parameters and liver. Continuous exposure to high concentrations of hexavalent chromium in drinking water results in intestinal tumors in mice but not rats. However, evidence of the carcinogenic potential of chromium has been demonstrated in rats but not consistently in mice. Cr (III) organic complexes (chromium picolinate) did not show evident adverse effects after repeated oral exposure. Both in vitro and in vivo data show that trivalent chromium is not genotoxic whilst hexavalent chromium is genotoxic. Chromium has been shown to affect sperm, estrous cycle and fetal development. Human toxicity data reveals mixed results but there is some evidence that hexavalent chromium can increase the risk of cancer. Data on Nickel show that nickel soluble compounds (nickel sulphate, nickel chloride or nickel nitrate) have acute and long term toxicity and produce oxidative stress and long term effects on liver. Less soluble compounds (nickel sulfides or nickel oxides) are less toxic. Nickel shows genotoxic effects both in vitro and in vivo. Only a limited number of studies on carcinogenic effects after oral exposure to nickel compounds are available. These studies showed no neoplastic effects in rats after oral administration. Nickel has been shown to affect sperm, live litter size and post-implantation loss. Teratogenic effects are reported on Amphibian embryos. Nickel can affect neurodifferentiation, the T-cell system and suppress the activity of natural killer cells. Human data reveals that nickel is excreted in the urine following oral exposure and that this increases with increasing age. There is some evidence that nickel might promote oral cancer etiology but no clear evidence that nickel can increase the risk of respiratory cancer.

Probiotic mitigates the toxic effects of potassium dichromate in a preclinical study: a randomized controlled trial

“…decrease in final body weight and decrease in daily weight gain and food efficiency) and also by parameters that assessed hepatic and renal function and integrity, as well as serum concentrations of proteins, albumin, globulins, glucose, triglycerides, total cholesterol and fractions. Similar results have also been observed in studies using water as a vehicle for administration of Cr (VI) and even at lower doses . Cr (VI) is capable of inducing oxidative stress through the formation of metabolic intermediates and final products generated during Cr (VI) reduction, which can participate in Fenton‐like reactions to generate hydroxyl radicals in the presence of hydrogen peroxide in the duodenum of mice and the small intestine of rats; through pathological analysis, a series of intestinal lesions was observed, including cytoplasmic vacuolization of villi, atrophy and apoptosis, in addition to which, after 3 months, ulcers in the digestive tract of rats, weight loss and decreased water consumption were reported .…”

“…This heavy metal can contaminate food and water and is capable of causing debilitating health complications, especially in the oxidation state VI [chromium (VI) or Cr (VI)], because it is very unstable, toxic and carcinogenic . In addition, repeated oral administration of Cr (VI) causes reduced body weight gain, altered biochemical parameters and oxidative stress indicators, and an alteration in hepatic and renal functions in rats …”

“…Cr (VI) can easily be transported through biological membranes and cause a range of toxic effects at the cellular and/or molecular level; however, the effects of probiotic supplementation in animals intoxicated with this metal incorporated in the feed are not clear. Therefore, the present study aimed to evaluate the nutritional, physiological and biochemical effects of supplementation with probiotic bacteria ( Lactobacillus acidophilus , Enterococcus faecium , Bifidobacterium thermophilum and Bifidobacterium longum ) in the feed of rats intoxicated with chromium (VI).…”

“…2,3 In addition, repeated oral administration of Cr (VI) causes reduced body weight gain, altered biochemical parameters and oxidative stress indicators, and an alteration in hepatic and renal functions in rats. 4 Microorganisms classified as probiotics have been suggested as an alternative approach to alleviate or prevent the deleterious effects of heavy metals because they have demonstrated beneficial effects in laboratory and preclinical studies when provided in isolation or association, in appropriate quantities and frequencies, 2,3,5 as a result of their activity as antioxidants, 6 free radical scavengers 7 and mitigators of the toxic effects of contaminating metals. 8 Cr (VI) can easily be transported through biological membranes and cause a range of toxic effects at the cellular and/or molecular level; 4 however, the effects of probiotic supplementation in animals intoxicated with this metal incorporated in the feed are not clear.…”

“…4 Microorganisms classified as probiotics have been suggested as an alternative approach to alleviate or prevent the deleterious effects of heavy metals because they have demonstrated beneficial effects in laboratory and preclinical studies when provided in isolation or association, in appropriate quantities and frequencies, 2,3,5 as a result of their activity as antioxidants, 6 free radical scavengers 7 and mitigators of the toxic effects of contaminating metals. 8 Cr (VI) can easily be transported through biological membranes and cause a range of toxic effects at the cellular and/or molecular level; 4 however, the effects of probiotic supplementation in animals intoxicated with this metal incorporated in the feed are not clear. Therefore, the present study aimed to evaluate the nutritional, physiological and biochemical effects of supplementation with probiotic bacteria (Lactobacillus acidophilus, Enterococcus faecium, Bifidobacterium thermophilum and Bifidobacterium longum) in the feed of rats intoxicated with chromium (VI).…”