Subchronic Low-Dose Methylmercury Exposure Accelerated Cerebral Telomere Shortening in Relevant with Declined Urinary aMT6s Level in Rats

Exposure to four typical heavy metals induced telomere shortening of peripheral blood mononuclear cells in relevant with declined urinary aMT6s in rats

Environmental heavy metals pollution have seriously threatened the health of human beings. An increasing number of researches have demonstrated that environmental heavy metals can influence the telomere length of Peripheral Blood Mononuclear Cells (PBMCs), which implicate biological aging as well as predicts diseases. Our previous study has shown that methylmercury (MeHg)-induced telomere shortening in rat brain tissue was associated with urinary melatonin metabolite 6-sulfatoxymelatonin (aMT6s) levels. Here, we aimed to further elucidate the impact of 4 typical heavy metals (As, Hg, Cd and Pb) on telomere length of PBMCs and their association with urinary aMT6s in rats. In this study, eighty-eight male Sprague-Dawley rats were randomized grouped into eleven groups. Among them, forty 3-month-old (young) and forty 12-month-old (middle-aged) rats were divided into young or middle-aged control groups as well as typical heavy metals exposed groups, respectively. Eight 24-month-old rats (old) was divided into aging control group. The results showed that MeHg exposure in young rats while sodium arsenite (iAs), MeHg, cadmium chloride (CdCl2), lead acetate (PbAc) exposure in middle-aged rats for 3 months significantly reduced the levels of and urinary aMT6s, as well as telomere length of PBMCs. In addition, they also induced abnormalities in serum oxidative stress (SOD, MDA and GPx) and inflammatory (IL-1β, IL-6 and TNF-α) indicators. Notably, there was a significant positive correlation between declined level of urinary aMT6s and the shortening of telomere length in PBMCs in rats exposed to 4 typical heavy metals. These results suggested that 4 typical heavy metals exposure could accelerate the reduction of telomere length of PBMCs partially by inducing oxidative stress and inflammatory in rats, while ageing may be an important synergistic factor. Urinary aMT6s detection may be a alternative method to reflect telomere toxic effects induced by heavy metal exposure.

Environmental Toxicology and Human Health

Humans and animals may be exposed on a continuous daily basis to a mixture of environmental contaminants that may act on several organ systems through differing mechanisms [...].

Synchrotron X-ray methods in the study of mercury neurotoxicology

In situ methods are valuable in all fields of research. In toxicology, the importance of dose is well known, elevating the need for in situ techniques to measure levels of toxicants and their byproducts in precise anatomically identifiable locations. More recently, additional emphasis has been placed on the value of techniques which can detect chemical form or speciation, which is equally important in the toxicology of a chemical compound. Many important but conventional methods risk losing valuable information due to extractions, digestions, or the general reliance on mobile phases. Few analytical tools possess the power and diversity of X-ray methods as in-situ methods. Here we present an overview, intended for toxicologists and pathologists, of a variety of synchrotron X-ray methods for determining in situ chemical form and distribution of heavier elements. The versatility and range of these synchrotron techniques, which are both established and emerging, is demonstrated in the context of the study of neurotoxicology of mercury, a global pollutant with the ability to harm both human health and the environment.