Assessment of genotoxicity of inorganic mercury in rats in vivo using both chromosomal aberration and comet assays

Abstract

The major objective of the present investigation was to assess the genotoxic effects of mercuric chloride (HgCl2), an inorganic mercury (Hg), in rats (Rattus norvegicus) using two different genetic endpoints, namely, chromosomal aberration (CA) and comet assays following both short-term (acute) and long-term (chronic) exposures. The study showed that the acute exposures to HgCl2 at 2 and 5 mg/kg body weight (b.w.) induced nonsignificant effects. HgCl2 at 10 and 12 mg/kg b.w. was significantly toxic and is exhibited by the induction of different types of CAs like chromatid breaks, chromosomal breaks, clumps and damaged cells and types of comets. HgCl2 at 15 mg/kg b.w. was found to be highly toxic, as mitostatic condition of cells were observed in CA assay. Chronic exposure to the lowest dose (2 mg/kg b.w.) of HgCl2 for 15 consecutive days produced a significant genotoxicity. Although Hg was found to induce both DNA strand breakage and chromosomal breaks in a dose-dependent manner, the results of the present investigation showed that the combination of comet and CA assays provided a better choice for assessing the genotoxicity of inorganicHg.

Advances in Understanding How Heavy Metal Pollution Triggers Gastric Cancer

“…Mercuric dichloride induced a significant increase in DNA migration in human salivary gland tissue cells and lymphocytes in carcinogenesis, as determined by the comet assay. Mercuric dichloride at 10 and 12 mg/kg body weight (BW) significantly induced several kinds of chromosomal aberrations, including chromatid and chromosomal breaks, clumps and damaged cells, and comets in rats [ 55 ]. Hg may also induce immune system dysfunction by inducing apoptosis in immune cells [ 36 ].…”

Intracellular accumulation and DNA damage caused by methylmercury in glial cells

“…[12,33] The presence of this biomarker of damage has been associated with the process of chromosomal elimination involved in aneuploidy, which may be related to the affinity of Hg with the sulfhydryl groups of tubulins, impairing spindle function. [7,14] In addition, micronuclei can represent fragments or entire chromosomes that failed to remain in the nucleus of daughter cells. [34] In this case, the ability to cause DNA double-strand breaks should be considered.…”

“…[ 12,13 ] Mercury genotoxicity has been associated with its affinity with the sulfhydryl groups of tubulins, impairing spindle function and leading to chromosomal aberrations, and also to its ability to produce free radicals, which can cause DNA damage. [ 7,14 ] In this regard, genotoxicity tests can be used to demonstrate both aneugenic effects, such as loss or gain of chromosomes, and DNA damage, such as single and double‐strand breaks. [ 15 ]…”

“…[12,13] Mercury genotoxicity has been associated with its affinity with the sulfhydryl groups of tubulins, impairing spindle function and leading to chromosomal aberrations, and also to its ability to produce free radicals, which can cause DNA damage. [7,14] In this regard, genotoxicity tests can be used to demonstrate both aneugenic effects, such as loss or gain of chromosomes, and DNA damage, such as single and double-strand breaks. [15] Therefore, considering the MeHg tropism for the nervous system, in which we have the interaction of two different types of cells, and that neoplastic cell lines are commonly used in toxicological studies and in vitro models aiming to assess the toxicity of mercury compounds, especially in the nervous system, [16][17][18][19] the present investigation attempted to evaluate comparatively the action of MeHg in an acute in vitro exposure in two cell lines representing neurons and glia cells, to contribute to a better understanding of the steps involved in the injuries and cell death processes caused by mercury exposure.…”

Relationship between genotoxicity and oxidative stress induced by mercury on common carp (Cyprinus carpio) tissues

“…MNi are formed during mitosis regardless of the type of damage that may have occurred during the cell cycle, and therefore DNA lesions are expressed in these structures only after one cell cycle and depend on the percentage of dividing cells and duration of the process (Fenech, 1997). On the other hand, the comet assay has been applied in species already used in biomonitoring and has proved to be a sensitive system for screening the potential genotoxicity of chemicals and complex mixtures (Bhowmik and Patra, 2012). This assay detects single-strand DNA breaks, alkalilabile sites and crosslinking (Tice et al, 2000).…”