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Epidemiological evidence has associated chronic exposure to inorganic arsenic with an increased occurrence of glucose intolerance and diabetes mellitus. Furthermore, inorganic arsenic induces oxidative stress in organs such as the liver. Betaine, as a methyl donor, plays a pivotal role in homocysteine metabolism. Betaine has antioxidant and anti-inflammatory properties. Therefore, the aim of this study was to evaluate the effects of betaine against sodium arsenite-induced diabetes and hepatotoxicity in mice. Forty-eight male mice were divided into 6 groups of 8. Group 1, received distilled water every day for 4 weeks by gavage. Group 2 received 500 mg/kg betaine every day for 4 weeks by gavage. Group 3 was given 10 mg/kg NaAsO 2 every day for 4 weeks by gavage. Groups 4, 5, and 6 were co-treated with 125, 250, and 500 mg/kg betaine half an hour before NaAsO 2 (10 mg/kg), respectively, daily for up to 4 weeks by gavage. After 28 days of the study, the mice were fasted overnight and on day 29, fasting blood glucose was measured and glucose tolerance test was performed. On day 30, the mice were anesthetized and a blood sample was taken from the heart. Serum factors (alanine aminotransferase, aspartate transaminase, and alkaline phosphatase activities), oxidative stress factors (malondialdehyde and glutathione levels, and the activity of superoxide dismutase, glutathione peroxidase, and catalase enzymes) and hepatic inflammatory factors (nitric oxide and tumor necrosis factor α) were measured. Histopathological studies were also performed on the liver and pancreas. In this study, it was shown that arsenic causes glucose intolerance, and oxidative/inflammatory hepatic damage. Co-administration of betaine prevents hepatotoxicity and glucose intolerance induced by arsenic in mice. Co-treatment of betaine with arsenic improved glucose intolerance and protected the liver against arsenic induced-oxidative damage and inflammation. Betaine at the dose of 500 mg/kg showed better results than the other doses. Accordingly, betaine can be suggested as a therapeutic agent against diabetogenic and hepatotoxic effects of arsenic., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Environmental pollutants and lifestyle both contribute to the rapidly increasing prevalence of type 2 diabetes mellitus (T2DM) worldwide. Evidence suggests that exposure to environmental contaminants such as arsenic is associated with impaired glucose metabolism and insulin signaling. In the present study, isolated rat liver mitochondria (1 mg/ml) were co-exposed to low concentration of arsenic trioxide (ATO) ( IC 25  = 40 µM) and hyperglycemic condition (20, 40, 80, 160 mM glucose or 20, 40, 80, 160 mM pyruvate (PYR)). Mitochondrial dehydrogenase activity (complex II), glutathione content (GSH), reactive oxygen species (ROS), lipid peroxidation, mitochondrial membrane potential (ΔΨ), and mitochondrial swelling were then evaluated in the presence of ATO 40 µM and PYR 40 mM. Unexpectedly, glucose alone (20, 40, 80, 160 mM) had no toxic effect on mitochondria, even at very high concentrations and even when combined with ATO. Interestingly, PYR at low concentrations (≤ 10 mM) has a protective effect on mitochondria, but at higher concentrations (≥ 40 mM) with ATO, it decreased the complex II activity and increased mitochondrial ROS production, lipid peroxidation, GSH depletion, mitochondrial membrane damage, and swelling (p < 0.05). In conclusion, PYR but not glucose increased ATO mitochondrial toxicity even at low concentrations. These results suggest that pre-diabetics with non-clinical hyperglycemia, who are inevitably exposed to low concentrations of arsenic through food and water, may develop mitochondrial dysfunction that accelerates their progression to diabetes over time., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Arsenic is found in soil, food, water and earth crust. Arsenic exposure is associated with chronic diseases such as cancer, cardiovascular disease as well as diabetes. One of complex effects of arsenic is on weight gain or loss. Involvement of arsenic in both weight loss and gain signaling pathways has previously been reported; however, too little attention has been paid to its weight reducing effect. Animal studies exhibited a role of arsenic in weight loss. In this regard, arsenic interference with endocrine system, leptin and adiponectin hormones as well as thermogenesis is more evidence. Apparently, arsenic-induced weight lossis generally meditated by its interaction with thermogenesis. In this review we have discussed the irregularities in metabolic pathways induced by arsenic that can lead to weight loss., (Copyright © 2021 Elsevier GmbH. All rights reserved.)

Background: Arsenic, an environmental pollutant, is a carcinogenic metalloid and also an anticancer agent., Objective: To evaluate the toxicity of arsenic nanoparticles in rat hepatocytes., Methods: Freshly isolated rat hepatocytes were exposed to 0, 20, 40, and 100 μM of arsenic nanoparticles and its bulk counterpart. Their viability, reactive oxygen species level, glutathione depletion, mitochondrial and lysosomal damage, and apoptosis were evaluated., Results: By all concentrations, lysosomal damage and apoptosis were clearly evident in hepatocytes exposed to arsenic nanoparticles. Evaluation of mitochondria and lysosomes revealed that lysosomes were highly damaged., Conclusion: Exposure to arsenic nanoparticles causes apoptosis and organelle impairment. The nanoparticles have potentially higher toxicity than the bulk arsenic. Lysosomes are highly affected. It seems that, instead of mitochondria, lysosomes are the first target organelles involved in the toxicity induced by arsenic nanoparticles.

Exposure to arsenic has been linked to the development of type 2 diabetes though its mechanism of toxicity remains unresolved. In this study berberine (BBR) effects on arsenic-induced sirtuin 3 (Sirt3) modifications in isolated mitochondria from rat pancreas were evaluated and compared with metformin (MET). With arsenic, mitochondrial reactive oxygen species (ROS), oxidative stress, and insulin resistance were obtained higher than control. From our results and in the presence of arsenic trioxide, insulin resistance and Sirt3 levels were found to be predominantly elevated that could be the result of compensating mechanisms. Apparently, BBR and MET recruit both direct (as an antioxidant) and indirect mechanisms (Sirt3 content) to deal with arsenic trioxide toxicity. Metformin compared with BBR exhibited a less significant effect on ROS levels and since its direct antioxidant property is minor, depressed the ROS level mainly through the Sirt3 modification., (© 2019 Wiley Periodicals, Inc.)

Background: A large body of evidence indicates that accumulation of oxidative stress originated from impaired mitochondrial respiratory chain is the main cause for the development of numerous diseases including diabetes and cancer. Arsenic exposure is a potential risk factor for type 2 diabetes development which, by disrupting mitochondrial respiration and SirT3 enzyme activity, enhances reactive oxygen species (ROS) level and evokes oxidative stress. In this study the impact of arsenic exposure on the mitochondrial function and SirT3 from rat's liver were examined in the presence or absence of metformin and berberine., Methods: Serum glucose and insulin levels were assessed in rats exposed to the diabetogenic concentration of arsenic. Isolated hepatocytes and mitochondria were then further evaluated to determine any deleterious consequences., Results: Diabetogenesis triggered by arsenic contributed to the mitochondrial ROS overproduction, impaired complex II activity, glucose homeostasis, glucose tolerance and insulin sensitivity. An increased SirT3 level indicated the compensatory mechanism to deal with this condition. Protective effect of metformin and berberine against these toxic insults were found to be associated with the mitochondrial SirT3 pathway. This pathway through the regulation of mitochondria-associated ROS production and glucose homeostasis in the liver may play a crucial role against the diabetogenic effect of arsenic., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Objectives: Health problems due to heavy metals have become a worldwide concern. Along with its carcinogenicity, arsenic exposure results in impairment of glucose metabolism and insulin secretion as well as altered gene expression and signal transduction. However, the exact mechanism behind the behaviour of arsenic on glucose homeostasis and insulin secretion has not yet been fully understood., Methods: Fasting blood sugar and glucose tolerance tests were evaluated., Results: In this study, we demonstrated that arsenic, when acutely administered, induced glucose intolerance in rats, although its chronic oral exposure did not provoke any glucose intolerance or hyperglycemia in rats. The protective activity of N-acetylcysteine, carvedilol and propranolol in male rats exposed to arsenic were also assessed, and N-acetylcysteine, particularly at 40 and 80 mg/kg, prevented the glucose intolerance induced in rats by arsenic., Conclusions: The present study showed that acute, but not chronic, contact with arsenic generates significant changes in the normal glucose tolerance pattern that may be due fundamentally to overproduction of reactive oxygen species and oxidative stress and is preventable by using N-acetylcysteine, a thiol-containing antioxidant., (Copyright © 2017 Diabetes Canada. Published by Elsevier Inc. All rights reserved.)

Obesity is a main reason of type 2 diabetes and also chronic exposure to arsenic (As) can produce diabetic symptoms. In previous studies, the association between high-fat diet and arsenic in the incidence of diabetes was found, but the role of beta cells activity, liver mitochondrial oxidative stress, and hepatic enzymes (leptin, adiponectin and beta amylase) was unclear. Thus, present study was conducted to evaluate the diabetogenic mechanism of arsenic followed by concomitant administration of high-fat diet (HFD) in male mice. In this experimental study, the mice consumed with HFD or low-fat diet (LFD) while exposed to As 25 or 50 ppm in drinking water for 20 weeks. At the end of experiments, hyperglycemia, insulin resistance variables, lipid profile, hepatic enzymes, liver mitochondrial oxidative stress, islet insulin secretion, liver, and pancreas histopathology were evaluated in all mice by their own methods. Control HFD fed mice showed a significant increase in FBG, OGTT, HOMA-IR, ITT, lipid profile, leptin, β-amylase, liver mitochondrial oxidative stress, hepatic enzymes and decreased FPI, HOMA-β, adiponectin, and islet insulin secretion or content. However, exposure to HFD concomitant with Arsenic revealed an impressive reduction in FBG, FPI, HOMA-IR, HOMA-β, ITT, lipid profile, and islet insulin secretion or content. This exposure enhanced OGTT, leptin, adiponectin, liver mitochondrial oxidative stress, and hepatic enzymes. In conclusion, HFD and arsenic concomitant administration induced impairment of OGTT and islet insulin secretion or content through the mitochondrial oxidative stress. [ABSTRACT FROM AUTHOR]

Aim: The aim of the present study was to evaluate the different doses of Butyric acid (BA) and Arsenic (As) in liver mitochondria oxidative stress and pancreatic islet insulin secretion of male mouse. Background: BA is found in many foods and As as a toxic metal is present in drinking water. They can induce oxidative stress in tissues. Methods: In this experimental study, Liver mitochondria were isolated by administration of the different centrifugation method and pancreatic islets were isolated by collagenase method. Mitochondria were incubated by BA (35, 75, 150, 300 µM) and As (20, 50, 100, 200 µM) as the islets were incubated by BA (250, 500, 1000, 1500 µM) and As (50, 100, 200 µM) for 1 hour. At the end of the experiment, mitochondrial viability and membrane potential, ROS, MDA, GSH and islets insulin secretion were measured by their specific methods. Results: BA and As administration increased mitochondrial levels of ROS, MDA and decreased GSH and pancreatic islet insulin secretion in a dose dependent manner (p<0.05). The doses of BA 75µM and As 100µM have been revealed the most mitochondria toxic concentrations. Also, the doses of 1000µM for BA and 100µM for As were considered as reducing concentrations for islets insulin secretion. Additionally, co administration of them intensified more these effects Conclusion: Alone or in combination administration of BA and As induced oxidative stress in liver mitochondria and decreased insulin secretion of pancreatic islets. [ABSTRACT FROM AUTHOR]