Airton da Cunha Martins

Arsenic speciation in Brazilian rice grains organically and traditionally cultivated: Is there any difference in arsenic content?

Inorganic arsenic contamination in rice is a global public concern due to the risks associated. In spite of being an important issue, few studies concerning differences between inorganic arsenic in rice grains under organic and conventional methods of cultivation are available in Brazil, which is an important producer and consumer. In the present work, samples of polished and husked rice (organic and conventional) and gastronomic rice (Arborio, Carnaroli and red/black rice) were analyzed and the results compared to FAO/Codex maximum limits. The total determination and speciation analysis of arsenic were carried out by ICP-MS and HPLC-ICP-MS, respectively. The results showed no significant statistical differences in total As concentration in organic rice (157.7±56.1ngg-1) vs. conventional rice (137.4±46.6ngg-1) and also in organic husked rice (227.7±95.5ngg-1) vs. conventional husked (217.7±60.9ngg-1). However, inorganic As was 45% higher in organic polished rice than in conventional polished rice and 41% higher in organic husked rice than in conventional husked rice. Gastronomic rice presented total arsenic ranging from 65.4 to 348ngg-1 for black and Arborio rice, respectively. Regarding the maximum levels adopted by Codex for i-As (200ngg-1), no violation was found.

Polymorphism of Metallothionein 2A Modifies Lead Body Burden in Workers Chronically Exposed to the Metal

Lead (Pb) is a metal that accumulates in the human body, inducing several adverse health effects. One of the proteins responsible for the distribution of metal in the body is metallothionein (MT), which is expressed by different genes, and it is supposed that genetic variation in the genes that encode MTs may affect the Pb body burden. The present study aimed to evaluate the genetic effects of the polymorphism of MT2A (single nucleotide polymorphism rs10636; C→G) on blood Pb levels (BLL) of workers from car battery factories who are chronically exposed to the metal. In total, 221 men participated in the study; genomic DNA from whole blood was extracted, and genotyping of MT2A was performed by TaqMan assays; BLL were quantified by inductively coupled plasma mass spectrometry (ICP-MS). BLL were 25 ± 14 µg/dl (range 1.9-68); BLL were positively correlated with duration of work and smoking status. Individuals who carried at least one C allele had higher BLL than those with the GG genotype (β = -0.45; p = 0.025, multivariable linear regression analyses). Taken together, our data support the hypothesis that polymorphisms in genes related to the transport of Pb, such as MTs, may modulate the concentrations of the metal in the body and, consequently, adverse health effects induced by Pb exposure.

Evaluation of distribution, redox parameters, and genotoxicity in Wistar rats co-exposed to silver and titanium dioxide nanoparticles

ABSTRACT The increasing production of silver nanoparticles (AgNPs) and titanium dioxide nanoparticles (TiO2NPs) has resulted in their elevated concentrations in the environment. This study was, therefore, aimed at determining the distribution, redox parameters, and genotoxic effects in male Wistar rats that were treated with either AgNP or TiO2NP individually, as well as under a co-exposure scenario. Animals were exposed via oral gavage to either sodium citrate buffer (vehicle), 0.5 mg/kg/day TiO2NP, 0.5 mg/kg/day AgNP or a mixture of TiO2NPs and AgNPs. Exposure lasted 45 days after which rats were sacrificed, and tissue biodistribution of Ag and Ti measured. The blood concentration of glutathione (GSH) and activities of glutathione peroxidase (GPx) and catalase (CAT) were determined while the genotoxicity was analyzed using the comet assay in peripheral blood and liver cells. The tissue concentrations of Ag followed the order; blood > liver > kidneys while for Ti the order was kidneys > liver > blood. There was no significant change in the measured redox parameters in animals that were exposed to TiO2NPs. However, there was a significant increase in GSH levels accompanied by a reduction in the GPx activity in AgNP-treated and co-exposed groups. The individual or co-exposure to TiO2NP and AgNP did not markedly induce genotoxicity in blood or liver cells. Data showed that TiO2NP did not produce significant oxidative stress or genotoxicity in rats at the dose used in this study while the same dose level of AgNPs resulted in oxidative stress, but no noticeable adverse genotoxic effects.

Effects of Lead Exposure and Genetic Polymorphisms on ALAD and GPx Activities in Brazilian Battery Workers

Lead (Pb) is a toxic metal that is widely used by metallurgical industries such as car battery recycling. Exposure to the metal may modify the redox status of the cells and consequently result in changes in activities of important enzymes such as delta-aminolevulinic acid dehydratase (ALAD) and glutathione peroxidase (GPx). Similarly, genetic polymorphisms may modulate the activities of enzymes related to detoxification processes of the metal and may modify Pb body burden. Therefore, the aims of the present study were (i) to evaluate the correlation between blood lead levels (BLL) and activities of the enzymes ALAD and GPx, and (ii) to determine whether activities of these enzymes may be influenced by polymorphisms in ALAD and GPx genes in Brazilian automotive battery workers chronically exposed to Pb, as well as the effects of these polymorphisms on BLL. Our study included 257 participants; BLL were determined by inductively couple plasma–mass spectrometry (ICP-MS), and the activities of the enzymes ALAD and GPx were quantified spectrophotometrically; and genotyping of ALAD (rs1800435) and GPx-1 (rs1800668) polymorphisms was performed by TaqMan assays (real-time polymerase chain reaction, RT-PCR). Significant negative correlations were found between BLL and ALAD activity. Subjects who carried at least one polymorphic allele for ALAD gene displayed markedly lower ALAD activities, while no significant effect was observed regarding GPx-1 polymorphism and activity of the same enzyme. Further, ALAD and GPx-1 polymorphisms exerted no marked influence on BLL. Taken together, our results showed that BLL affected ALAD but not GPx activities, and these were not modulated by polymorphisms in ALAD and GPx gene. Further, the rs1800435 SNP showed a tendency to modulate ALAD activity, while the rs1800668 SNP did not modulate GPx activity in Brazilian automotive battery workers exposed to Pb.

A perspective of mitochondrial dysfunction in rats treated with silver and titanium nanoparticles (AgNPs and TiNPs)

Nanotechnology is a growing branch of science that deals with the development of structural features bearing at least one dimension in the nano range. More specifically, nanomaterials are defined as objects with dimensions that range from 1 to 100 nm, which give rise to interesting properties. In particular, silver and titanium nanoparticles (AgNPs and TiNPs, respectively) are known for their biological and biomedical properties and are often used in consumer products such as cosmetics, food additives, kitchen utensils, and toys. This situation has increased environmental and occupational exposure to AgNPs and TiNPs, which has placed demand for the risk assessment of NPs. Indeed, the same properties that make nanomaterials so attractive could also prove deleterious to biological systems. Of particular concern is the effect of NPs on mitochondria because these organelles play an essential role in cellular homeostasis. In this scenario, this work aimed to study how AgNPs and TiNPs interact with the mitochondrial respiration chain and to analyze how this interaction interferes in the bioenergetics and oxidative state of the organelles after sub-chronic exposure. Mitochondria were exposed to the NPs by gavage treatment for 21 days to check whether co-exposure of the organelles to the two types of NPs elicited any mitochondrion-NP interaction. More specifically, male Wistar rats were randomly assigned to four groups. Groups I, II, III, and IV received mineral oil, TiNPs (100 μg/kg/day), AgNPs (100 μg/kg/day), and TiNPs + AgNPs (100 μg/kg/day), respectively, by gavage. The liver was immediately removed, and the mitochondria were isolated and used within 3 h. Exposure of mitochondria to TiNPs + AgNPs lowered the respiratory control ratio, causing an uncoupling effect in the oxidative phosphorylation system. Moreover, both types of NPs induced mitochondrial swelling. Extended exposure of mitochondria to the NPs maintained increased ROS levels and depleted the endogenous antioxidant system. The AgNPs and TiNPs acted synergistically-the intensity of the toxic effect on the mitochondrial redox state was more significant in the presence of both types of NPs. These findings imply that the action of the NPs on mitochondria underlie NP toxicity, so future application of NPs requires special attention.

Arsenic, cadmium, and mercury-induced hypertension: mechanisms and epidemiological findings

ABSTRACT Arsenic (As), cadmium (Cd), and mercury (Hg) are toxic elements widely distributed in the environment. Exposure to these elements was attributed to produce several acute and chronic illnesses including hypertension. The aim of this review is to provide a summary of the most frequently proposed mechanisms underlying hypertension associated with As, Cd, and Hg exposure including: oxidative stress, impaired nitric oxide (NO) signaling, modified vascular response to neurotransmitters and disturbed vascular muscle Ca2+ signaling, renal damage, and interference with the renin–angiotensin system. Due to the complexity of the vascular system, a combination rather than a singular mechanism needs to be considered. In addition, epidemiological findings showing the relationship between various biomarkers of metal exposure and hypertension are described. Given the complex etiology of hypertension, further epidemiological studies evaluating the roles of confounding factors such as age, gender, and life style are still necessary.

Ascorbic acid supplementation ameliorates testicular hormonal signaling, sperm production and oxidative stress in male rats exposed to rosuvastatin during pre-puberty: Statin and vitamin C on male rat reproduction

Dyslipidemias are occurring earlier in the population due to the augmentation of obesity. Rosuvastatin reduces cholesterol and triglycerides; however, previous studies have shown that it may affect male reproduction. Ascorbic acid (AA), an antioxidant compound, plays a protective role in the male reproductive system. This study aimed to evaluate whether pre‐pubertal exposure to rosuvastatin may impair testicular structure and antioxidant status in male rats and if supplementation with AA may alleviate these damages. Male rats were randomly divided into six experimental groups (n = 10) on postnatal day (PND) 23 and received the different treatments by gavage from PND 23 to 53. The experimental groups received vehicle (saline solution 0.9%), 3 or 10 mg/kg/day of rosuvastatin diluted in saline solution 0.9%, supplementation with 150 mg/day of AA, 3 mg/kg/day of rosuvastatin in association with 150 mg/day of AA or 10 mg/kg/day of rosuvastatin associated with 150 mg/day of AA. Testicular parameters were assessed on PND 53 and 110. There were diminished androgen receptors staining in the Sertoli cells and increased germ cell death in rosuvastatin‐exposed groups, in both periods. Spermatids showed lower estrogen alpha‐receptors staining in the group exposed to 10 mg of statin at adulthood. There were androgen depletion and increased lipid peroxidation and catalase activity in statin‐exposed groups. Rosuvastatin exposure during pre‐puberty impaired testicular structure, steroid receptor distribution and increased oxidative stress; however, AA was able to ameliorate the impairment provoked by statin exposure.

Chrysin Administration Protects against Oxidative Damage in Varicocele-Induced Adult Rats

Oxidative stress is known as the leading factor responsible for varicocele-related infertility and for that reason, many antioxidant therapies have been proposed. Considering that, we evaluated the reproductive outcomes and fertility of varicocelized rats and the impact of chrysin within these parameters. The animals were allocated into three groups: sham (control), varicocele treated via gavage with 50 mg/kg/day of chrysin (V1), or vehicle (V2) for 56 days. Chrysin treatment prevented oxidative damage resulting from varicocele by decreasing testicular concentrations of malondialdehyde and sperm DNA fragmentation. It also improved histological aspect of the testis and maintained morphometric parameters similar to the sham group. Furthermore, there were no differences in body and reproductive organ weights, histopathological analysis of epididymis, sperm counts and morphology, testosterone levels, sexual behavior, and fertility parameters among experimental groups. Our results reinforce the idea that injuries provoked by experimental varicocele are related, at least in part, to oxidative stress. Moreover, varicocele showed bilateral deleterious effects without interfering with fertility. Chrysin administration significantly ameliorated sperm parameters, protecting the reproductive system against varicocele damages. For that reason, chrysin might be an alternative adjuvant therapy to improve sperm quality in men presenting this condition.