Comparative histological studies on liver of mice exposed to Cr(VI) and Cr(V) compounds

Abstract

<jats:p> Chromium toxicity is strongly dependent on its oxidation state. Cr(VI) is carcinogenic and mutagenic, although its in vivo and in vitro toxic effects are related to its intracellular fate. Inside the cells, Cr(VI) is rapidly reduced to stable Cr(III). As Cr(V) and Cr(IV) species have been reported to be formed in the Cr(VI) reduction pathways, Cr(VI)induced damage is thought, at least in part, to arise from these hypervalent species. The study of Cr(VI) reduction mechanisms and the characterization of the effects of each reactive intermediate constitute important steps towards a better understanding of chromium toxicity. The purpose of this work is to enlarge the scope of Cr(VI)induced alterations in mouse to other chromium species. Our studies have led to the in situ preparation of a new Cr(V) complex, [Cr<jats:sup>V</jats:sup>–BT]<jats:sup>2–</jats:sup>, a stable compound at neutral pH, which mimics Cr(VI) reduction intermediates. The effect of Cr(V) on the histology of mice liver is assessed and compared with similar Cr(VI) assays. Liver toxicity was examined after single administrations of Cr(VI) or [Cr<jats:sup>V</jats:sup>–BT]<jats:sup>2–</jats:sup> to mice. Both compounds produced reversible hepatic damage in a time-dependent manner. However, Cr(V) toxic effects have proved to be more rapid than with Cr(VI), permitting the role of Cr(VI) intermediates formed during intracellular chromium reduction to be highlighted. </jats:p>

Melatonin protects against chromium (VI) induced hepatic oxidative stress and toxicity: Duration dependent study with realistic dosage

“…These changes are very prominently manifested in 60-day liver sections indicating increasing cytotoxicity due to Cr (VI) exposure. In support of these observations are some reports based on both in vitro and in vivo studies indicating hepatic histological lesions, DNA damage and apoptosis with short-term exposure to Cr (da Neves et al, 2002 ; Da Silva et al, 2006 ; Wang et al, 2006 ). The acute single dose study of da Neves et al .…”

“…The acute single dose study of da Neves et al . ( 2002 ) documented vacuolation and hypertrophy of hepatocytes with disorganization of hepatic parenchyma. The study of da Silva et al ( 2006 ), using a dosage of Cr similar to that of the present study given through drinking water for a protracted period of 120 days, reported varying degrees of parenchymal cell vacuolization with many hepatocytes depicting ballooned appearance with karyolysis.…”

The Protective and Antidotal Effects of Taurine on Hexavalent Chromium-Induced Oxidative Stress in Mice Liver Tissue

“…Hojo et al [40] reported that the Cr(V) and Cr(IV) compounds enhanced lipid peroxidation in liver and kidney homogenates more strongly than the Cr(VI) compound. In another report, both Cr(VI) and Cr(V) were shown to induce reversible hepatic damage; however, the toxicity of Cr(V) was observed more rapidly than that of Cr(VI) [41]. Therefore, involvement of transient chromium intermediate states and their related free radicals formation might be a possible mechanism in Cr(VI)-induced toxicity.…”

Effect of Cr(V) on reproductive organ morphology and sperm parameters: An experimental study in mice

“…Recent works concern, for example, kidney and liver [10,14], pancreas [15], lungs [6,16-18], brain [19], male reproductive organs [20], skin [21], or even blood [22]. These studies have comprised both particulate chromium compounds, mainly related with lung pathology [16], together with soluble compounds containing chromium in all the available oxidation states, more adequate or available to reach other target organs.…”

“…In previous works we have undertaken studies on Cr(VI) and Cr(V) induced alterations on mouse liver [14], and spleen histology [23]. Also, the functional properties of Sertoli cells from mice exposed to Cr(V) were investigated [24].…”