Organ and subcellular distribution of selenium in rats exposed to cadmium, mercury, and selenium

Hepato- and nephroprotective effects of bradykinin potentiating factor from scorpion (Buthus occitanus) venom on mercuric chloride-treated rats

Bioactive peptides such as bradykinin potentiating factor (BPF), have, anti-oxidative, anti-inflammatory, immunomodulatory and ameliorative effects in chronic diseases and play a potential role in cancer prevention. It is known that the liver and kidney accumulate inorganic mercury upon exposure, which often leads to mercury intoxication in these organs. In this study, we investigated the effect of bradykinin potentiating factor (BPF), a scorpion venom peptide, on mercuric chloride-induced hepatic and renal toxicity in rats. We used 20 adult male Albino rats divided into four equal groups: the first group was injected with saline (control); the second group was administered daily with mercuric chloride (HgCl₂) for 2 weeks; the third group was administered with BPF twice weekly for 2 successive weeks, while the fourth group was exposed to BPF followed by HgCl₂. We observed that HgCl₂ treated rats had a significant increase in serum ALT, AST, ALP, creatinine and urea levels compared to control. Furthermore, HgCl₂ treated rats showed a marked decrease in total proteins, albumin and uric acids compared to control. The previously studied parameters were not significantly changed in BPF pretreated rats compared to control. Moreover, a significant decrease in the activities of glutathione perioxidase (GSH), superoxide dismutase (SOD), and catalase (CAT), in addition to a significant increase in the level of malondialdehyde (MDA) were observed in hepatic and renal tissues of rats after HgCl₂ treatment. In contrast, the HgCl₂/BPF treated rats showed a significant elevation in the activity of GSH, SOD, and CAT accompanied with a significant regression in the level of MDA compared to the HgCl₂ exposed rats. We conclude that treatment with BPF is a promising prophylactic approach for the management of mercuric chloride-induced hepato- and nephro-toxicities.

Effect of type of muscle and Cu supplementation on trace element concentrations in cattle meat

Considering that meat is an important source of metals exposure to humans it is important to explore trace element concentrations in different types of muscles. Because of the demonstrated effect of Cu-supplementation on mineral status, the influence of Cu-supplementation was also evaluated. Samples of four different muscles (diaphragm, cardiac, semitendinous and pectoral, n=120) from beef calves receiving typical commercial diets Cu-supplemented (15 mg Cu(2)SO(4)/kg DM) and non-supplemented were taken and acid digested. The levels of non-essential (As, Cd, Hg, Pb and Sn) and essential (Co, Cr, Fe, Mn, Mo, Ni, Se and Zn) elements were analyzed by ICP-MS. The statistical analyzes included two way Anova, post hoc DHS Tukey and Spearman correlations. The most active and less fat containing muscles showed in general the highest essential and the lowest non-essential trace element accumulation. As and Hg muscular residues are indicative of animal exposure, however, in situations of an adequate mineral status, essential trace element concentrations in muscle are irrespective of the mineral status of the animal and could be possibly related to their own particular muscular metabolism. Cu-supplementation significantly reduced As but caused a significant decrease of Se, which could have significance for the animal's health.

Cadmium and Selenium Interaction in Mammals

Izloženost kadmiju neizbježna je zbog njegove sveprisutnosti u okolišu kao prirodne sastavnice Zemljine kore i kao onečišćenja. Kadmij može izazvati toksične učinke u gotovo cijelom organizmu vezanjem za biološke strukture i nakupljanjem u tkivima, poticanjem stvaranja slobodnih radikala, kao i međudjelovanjem s esencijalnim elementima, često u obliku antagonizma. S druge strane, dodatnim unosom esencijalnih elemenata može se utjecati na raspodjelu i štetne učinke kadmija. Selenij je esencijalan mikroelement i antioksidans, a zbog svojstva vezanja za kadmij (kao i živu, arsen i druge toksične elemente) te uloge u detoksifikaciji, detaljnije se počelo istraživati međudjelovanje kadmija i selenija. U radu je dan pregled dosadašnjih saznanja o toksikokinetici i toksikodinamici kadmija, biokinetici i biodinamici selenija i mehanizmima njihova međudjelovanja proizašlih uglavnom iz istraživanja na životinjama i ograničenu broju istraživanja u ljudima. Različite doze i odnos doza, način i dužina izloženosti kadmiju i seleniju u pokusima na životinjama uzrok su često vrlo oprečnih rezultata istraživanja opisanih u literaturi. Buduća istraživanja međudjelovanja kadmija i selenija treba usmjeriti na osjetljive skupine stanovništva i na istraživanje mehanizama tog međudjelovanja. Doze i izloženost u pokusima na životinjama treba prilagoditi dugotrajnim i niskim razinama izloženosti koje su najčešće u ljudi.

Distribution of exogenous heavy metals in the hepatocytes of calves: a morphometric study

The objective of this study was to evaluate the presence of heavy metals in the hepatocytes of the animals fed a cadmium-supplemented diet and also receiving zinc and/or selenium in the injection form. The experiment involved four groups of calves (6-8, both sexes) receiving the heavy metals in various combinations for 95 days. Electron micrographs of liver cells were prepared and statistically evaluated using Student's t-test. A modified morphometric apparatus was used for morphometric examination. Exogenous cadmium showed marked accumulation in the hepatocytes. If, however, the cadmium diet was combined with zinc or selenium administration the amount of the reduction product was much lower.

Effect of Cd on tissue levels of Se, Zn, Fe, Co and Rb

The interaction of Cd (as CdCl2) with organic Se-compounds and SeO2 was investigated. Instrumental neutron activation analysis was applied as the analytical method. Concentrations of Se in liver and kidneys were always significantly higher after simultaneous i.p. injections with Cd and Se-compounds in comparison with single Se-injection. Cd or Se-injections also affect the content of Zn, Fe, Co and Rb in all the investigated organs. We suggested that the formation of Cd-Se-protein complexes allow for an orderly transfer of Cd to metallothionein (MT). The results showed that Cd was a very effective inducer of MT, and the maximum formation of MT was observed in the liver.

Zinc-selenium interaction in the rat

Retention, dynamics of 75Se and 65Zn distribution, and elimination were studied in rats after separate or joint single doses of these metals. White female Wistar rats were divided into four groups (fifteen rats each). Group I received Na2(75)SeO3 (0.1 mg Se/kg i.g.), group II received Na2(75)SeO3 + ZnCl2 (5 mg Zn/kg s.c.), group III received 65ZnCl2, and group IV received 65ZnCl2 + Na2SeO3. The zinc and selenium contents in the tissues were estimated during 120 h after administration; excretion in urine and feces of animals was determined throughout the experiment. Combined administration of zinc and selenium resulted in an enhanced selenium retention in the brain, spleen, kidneys, blood, lungs, and heart. A selenium-induced increase in the concentration of zinc was noted in the bowels, blood, liver, kidneys, spleen, brain, and lungs. The effects of the zinc/selenium interaction were visible especially in the lowered level of excretion of these elements. Zinc induced a decrease in the excretion of selenium in urine, with no concomitant changes in the excretion in feces. However, a visible decrease in the excretion of zinc in the feces was observed in the presence of selenium. The present results indicate an occurrence of clear-cut interaction effects between zinc and selenium administered simultaneously in the rat.