Examinando por Autor "Dalton Valentim Vassallo"

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Aluminum exposure for 60 days at an equivalent human dietary level promotes peripheral dysfunction in rats
(Elsevier, 2017-08-25) Caroline Silveira Martinez; Uranga, Jose Antonio; Franck Maciel Peçanha; Dalton Valentim Vassallo; Vera, Gema; Miguel, Marta; Giulia Alessandra Wiggers
Aluminum (Al) is a neurotoxic associated with a number of chronic human diseases. We investigated the effects of Al exposure at doses similar to human dietary levels on the peripheral nervous system over a 60 day period. Wistar male rats were divided into two major groups and received orally: 1) Low aluminum level - rats were subdivided and treated for 60 days as follows: a) Untreated - ultrapure water; b) AlCl3 at a dose of 8.3 mg/kg bw for 60 days, representing human Al exposure by diet; and 2) High aluminum level - rats were subdivided and treated for 42 days as follows: C) Untreated – ultrapure water; d) AlCl3 at 100 mg/kg bw for 42 days, representing a high level of human exposure to Al. Von Frey hair and plantar tests were used to verify the tactile and thermal sensitivities, respectively. The presence of catalepsy behavior and the spontaneous motor activity were investigated by “ring test” and using individual photocell activity chambers. Reactive oxygen species, lipid peroxidation and total antioxidant capacity in plasma, were measured. Immunohistochemistry to investigate the nerve inflammation and, the specific presence of Al in the sciatic nerve fibers were investigated. Al exposure at a representative human dietary level promotes the development of mechanical allodynia, catalepsy behavior, increased the number of activated macrophages in the sciatic nerve, systemic oxidative stress and, is able to be retained among the sciatic nerve fibers. The effects of Al in the peripheral nervous system were similar to those found in rats exposed to Al at a dose much higher (100 mg/kg). Therefore, our findings suggest that Al may be considered toxic for the peripheral nervous system, thus inducing peripheral dysfunction.
Aluminum Exposure for 60 days at Human Dietary Levels Impairs Spermatogenesis and Sperm Quality in Rats
(Elsevier, 2017-10) Caroline Silveira Martinez; Alyne Gourlart Escobar; José Antonio Uranga-Ocio; Franck Maciel Peçanha; Dalton Valentim Vassallo; Christopher Exley; Marta Miguel; Giulia Alessandra Wiggers
Concerns about environmental aluminum (Al) and reproductive health have been raised. We investigatedthe effects of Al exposure at a human relevant dietary level and a high level exposure to Al. Experiment 1(Lower level) rats were treated orally for 60 days: a) controls – ultrapure water; b) aluminum at 1.5 mg/kgbw/day and c) aluminum at 8.3 mg/kg bw/day. Experiment 2 (High level) rats were treated for 42 days:a) controls – ultrapure water; b) aluminum at 100 mg/kg bw/day. Al decreased sperm count, daily spermproduction, sperm motility, normal morphological sperm, impaired testis histology; increased oxidativestress in reproductive organs and inflammation in testis. Our study shows the specific presence of Alin the germinative cells and, that low concentrations of Al in testes (3.35 _g/g) are sufficient to impairspermatogenesis and sperm quality. Our findings provide a better understanding of the reproductivehealth risk of Al.
Ameliorative effects of egg white hydrolysate on recognition memory impairments associated with chronic exposure to low mercury concentration
(Elsevier, 2016-12) Rizzetti, Danize Aparecida; Caroline Dalla Colletta Altermann; Caroline Silveira Martinez; Franck Maciel Peçanha; Dalton Valentim Vassallo; Uranga Ocio, Jose Antonio; Miguel, Marta; Wiggers, Giulia Alessandra; Pâmela Billig Mello-Carpes
The study aimed to investigate if the EWH is able to prevent the recognition memory disorders associated with long-term Hg exposure in rats. For this, male Wistar rats were treated for 60 days with: a) Untreated: saline solution (i.m.); b) Hydrolysate: EWH (1 g/kg/day, gavage); c) Mercury: HgCl2 (1st dose 4.6 μg/kg, subsequent doses 0.07 μg/kg/day, i.m.); d) Hydrolysate-Mercury. Object recognition memory test was performed to verify Short (STM) and Long-Term Memory (LTM) and Open Field, Plus Maze and Tail Flick tests were performed as control for behavioral experiments. Reactive Oxygen Species (ROS) in hippocampus were determined by dichlorofluorescein diacetate (DCFH-DA) method, malondialdehyde (MDA) levels by TBARS, antioxidant power by FRAP assay and total Hg concentration by atomic fluorescence spectrometry. We confirm that the STM and LTM were impaired in adult rats exposed to Hg at low concentrations, which may be related to the increased metal deposition, ROS production and subsequently the oxidative damage in hippocampus. In addition, we demonstrated for the first time that EWH treatment is able to prevent memory impairment induced by Hg exposure, reducing Hg content and ROS production in hippocampus. In conclusion, EWH ameliorates memory impairments induced by chronic exposure to low doses of Hg. These findings may represent a good public health strategy since they indicate that EWH is a promising candidate as a new natural therapy for heavy metals intoxication.
Egg white-derived peptides prevent male reproductive dysfunction induced by mercury in rats
(Elsevier, 2016-12-30) Danize Aparecida Rizzetti; Caroline Silveira Martinez; Alyne Goulart Escobar; Taiz Martins da Silva; Uranga, Jose Antonio; Franck Maciel Peçanha; Dalton Valentim Vassallo; Marta, Castro; Giulia Alessandra Wiggers
Oxidative stress in known to contribute to the male reproductive dysfunction induced by mercury (Hg). Our study tested the hypothesis that the egg white hydrolysate (EWH), a potent antioxidant in vitro, is able to prevent the effects of prolonged Hg exposure on male reproductive system in rats. For this, rats were treated for 60 days with: a) Untreated - saline solution (i.m.); b) Hydrolysate - EWH (1 g/kg/day, gavage); c) Mercury - HgCl2 (1st dose 4.6 mg/kg, subsequent doses 0.07 mg/kg/day, i.m.); d) Hydrolysate- Mercury. At the end of the treatment, sperm motility, count and morphological studies were performed; Reactive Oxygen Species (ROS) levels, lipid peroxidation, antioxidant capacity, histological and immu- nohistochemical assays on testis and epididymis were also carried out. As results, HgCl2-treatment decreased sperm number, increased sperm transit time in epididymis and impaired sperm morphology. However, these harmful effects were prevented by EWH. HgCl2-treatment also increased ROS levels, lipid peroxidation and antioxidant capacity in testis and epididymis as well as promoted testicular inflammation and histological changes in epididymis. EWH improved histological and immunohistochemical alterations, probably due to its antioxidant property. In conclusion, the EWH could represent a powerful natural alternative to protect the male reproductive system against Hg-induced sperm toxicity.
Potential benefits of egg white hydrolysate in the prevention of Hg-induced dysfunction in adipose tissue
(2022) Danize Aparecida Rizzetti; Patricia Corrales; Uranga, Jose Antonio; Gema Medina-Gómez; Franck Maciel Peçanha; Dalton Valentim Vassallo; Miguel, Marta; Giulia Alessandra Wiggers
Aim: To investigate the effects of egg white hydrolysate (EWH) on the lipid and glycemic metabolism disruption in the white adipose tissue (WAT) dysfunction induced by mercury (Hg). Experimental: Wistar rats were treated for 60 days: control (saline, intramuscular – i.m.); hydrolysate (EWH, gavage, 1 g kg−1 day−1); mercury (HgCl2, i.m., 1st dose 4.6 μg kg−1, subsequent doses 0.07 μg kg−1 day−1) and hydrolysate-mercury (EWH-HgCl2). Hg level and histological analyses were performed in epididymal WAT (eWAT), pancreas and liver. GRP78, CHOP, PPARα, PPARγ, leptin, adiponectin, and CD11 mRNA expressions were analyzed in eWAT. The plasma lipid profile, glucose, and insulin levels were measured. Antioxidant status was also evaluated in the plasma and liver. Results: EWH intake prevented the reduced eWAT weight, adipocyte size, insulin levels, and antioxidant defenses and the increased glucose and triglyceride levels induced by Hg exposure; hepatic glutathione levels were higher in rats co-treated with EWH. The increased mRNA expression of CHOP, PPARα, and leptin induced by Hg was reduced in co-treated rats. EWH did not modify the elevated mRNA expression of GRP78, PPARγ and adiponectin in Hg-treated rats. Increased levels of Hg were found in the liver; the co-treatment did not alter this parameter. EWH prevented the morphological and metabolic disorder induced by Hg, by improving antioxidant defenses, inactivating pro-apoptotic pathways and normalizing the mRNA expression of PPARs and adipokines. Its effects enabled an increase in insulin levels and a normal balance between the fat storage and expenditure mechanisms in WAT. Conclusions: EWH may have potential benefits in the prevention and management of Hg-related metabolic disorders.