An increase of oxidative stress markers and the alteration of the antioxidant enzymatic system are associated with spleen damage caused by methimazole-induced hypothyroidism

Predicting Drugs Suspected of Causing Adverse Drug Reactions Using Graph Features and Attention Mechanisms

BACKGROUND

Adverse drug reactions (ADRs) refer to an unintended harmful reaction that occurs after the administration of a medication for therapeutic purposes, which is unrelated to the intended pharmacological action of the drug. In the United States, ADRs account for 6% of all hospital admissions annually. The cost of ADR-related illnesses in 2016 was estimated at USD 528.4 billion. Increasing the awareness of ADRs is an effective measure to prevent them. Assessing suspected drugs in adverse events helps to enhance the awareness of ADRs.

METHODS

In this study, a suspect drug assisted judgment model (SDAJM) is designed to identify suspected drugs in adverse events. This framework utilizes the graph isomorphism network (GIN) and an attention mechanism to extract features based on patients' demographic information, drug information, and ADR information.

RESULTS

By comparing it with other models, the results of various tests show that this model performs well in predicting the suspected drugs in adverse reaction events. ADR signal detection was conducted on a group of cardiovascular system drugs, and case analyses were performed on two classic drugs, Mexiletine and Captopril, as well as on two classic antithyroid drugs. The results indicate that the model can accomplish the task of predicting drug ADRs. Validation using benchmark datasets from ten drug discovery domains shows that the model is applicable to classification tasks on the Tox21 and SIDER datasets.

CONCLUSIONS

This study applies deep learning methods to construct the SDAJM model for three purposes: (1) identifying drugs suspected to cause adverse drug events (ADEs), (2) predicting the ADRs of drugs, and (3) other drug discovery tasks. The results indicate that this method can offer new directions for research in the field of ADRs.

Toxicological analysis of synthetic dye orange red on expression of NFκB-mediated inflammatory markers in Wistar rats

Orange red is a food and cosmetic coloring agent made by the amalgamation of two azo dyes carmoisine and sunset yellow.The current study demonstrates the effect of different concentrations of orange red on antioxidant status, inflammatory biomarkers (TNFα, IFNγ, IL1β, IL6, COX-2, iNOS, and NFκB/p65), biochemical enzymes, and liver histology. In totality, 25 male Wistar rats were procured and arbitrarily alienated into 5 different groups each with 5 animals. Group I was taken as the control. Groups II-V were designated as treatment groups. Groups II and III were administered with (5 and 25 mg/kg b.wt.) and groups IV and V with (150 and 300 mg/kg b.wt.) of orange red via oral gavage for 30 days. It was observed that both low and high concentrations of orange red (25, 150, and 300 mg/kg) remarkably augmented the levels of serum inflammatory cytokines (TNFα, IFNγ, IL1β, and IL6) and the protein and gene expression of COX-2, iNOS, and NFκB/p65. A significant decrease in glutathione reductase, glutathione peroxidase, glutathione-S-transferase, superoxidase dismutase, and catalase activity was observed with increasing concentration of orange red. Furthermore, an increase in the level of several vital biochemical parameters and damage severity to hepatic tissue was also found dose dependent.

Phycocyanobilin is the molecule responsible for the nephroprotective action of phycocyanin in acute kidney injury caused by mercury

C-Phycocyanin (CPC) exerts therapeutic, antioxidant, anti-inflammatory and immunomodulatory actions. It prevents oxidative stress and acute kidney damage caused by HgCl₂. However, the exact mechanism of the pharmacological action of C-phycocyanin is as yet unclear. Some proposals express that CPC metabolism releases the active compound phycocyanobilin (PCB) that is able to induce CPC's therapeutical effects as an antioxidant, anti-inflammatory and nephroprotective. This study is aimed to demonstrate that PCB is the molecule responsible for C-phycocyanin's nephroprotective action in the acute kidney injury model caused by HgCl₂. PCB was purified from C-phycocyanin and characterized by spectroscopy and mass spectrometry methods. Thirty-six male mice were administrated with 0.75, 1.5, or 3 mg per kg per d of PCB 30 min before the 5 mg kg^-1 HgCl₂ administration. PCB was administered during the following five days, after which the mice were euthanized. Kidneys were dissected to determine oxidative stress and redox environment markers, first-line antioxidant enzymes, effector caspase activities, and kidney damage markers.The quality of purified PCB was evaluated by spectroscopy and mass spectrometry. All PCB doses prevented alterations in oxidative stress markers, antioxidant enzymes, and caspase 9 activities. However, only the dose of 3 mg per kg per d PCB avoided the redox environment disturbance produced by mercury. All doses of PCB partially prevented the down-expression of nephrin and podocin with a consequent reduction in the damage score in a dose-effect manner. In conclusion, it was proven that phycocyanobilin is the molecule responsible for C-phycocyanin's nephroprotective action on acute kidney injury caused by mercury.

Protective Effect of Epigallocatechin-3-Gallate in Hydrogen Peroxide-Induced Oxidative Damage in Chicken Lymphocytes

Epigallocatechin-3-gallate (EGCG) is one of the fundamental compounds in green tea. The present study was to evaluate the protective effect of EGCG in oxidative damage and apoptosis induced by hydrogen peroxide (H₂O₂) in chicken lymphocytes. Results showed that preincubation of lymphocytes with EGCG significantly decreased H₂O₂-reduced cell viability and apoptotic cells with DNA damage, restored the H₂O₂-dependent reduction in total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-PX), superoxide dismutase (SOD), glutathione (GSH), and glutathione disulfide (GSSG), and suppressed the increase in intracellular reactive oxygen species (ROS), nitric oxide (NO), nitric oxide synthesis (NOS), malondialdehyde (MDA), lipid peroxide (LPO), and protein carbonyl (Carbonyl). In addition, preincubation of the cells with EGCG increased mitochondrial membrane potential (MMP) and reduced calcium ion ([Ca²⁺]i) load. The protective effect of EGCG in oxidative damage in lymphocytes was accompanied by mRNA expression of SOD, Heme oxygenase-1 (HO-1), Catalase (CAT), GSH-PX, nuclear factor erythroid 2-related factor 2 (Nrf2), and thioredoxin-1 (Trx-1). As EGCG had been removed before lymphocytes were challenged with H₂O₂, the activation of genes such as Nrf2 and Trx-1 by preincubation with EGCG could be the main reason for EGCG to protect the cells from oxidative damage by H₂O_2. Since oxidative stress is an important mechanism of biological damage and is regarded as the reasons of several pathologies, the present findings may be helpful for the use of tea products to prevent oxidative stress and maintain healthy in both humans and animals.

Effect of myrtle (Myrtus communis L.) essential oil on oxidant-antioxidant balance in rats with propylthiouracil-induced hypothyroidism

Among today's health problems, metabolic diseases are at the forefront. Hypothyroidism (HT) is a disease characterized by increased TSH, decreased T3&T4 concentrations in serum, with overall metabolic slowdown. Although there are many studies in the literature about oxidative status in HT, statements in these studies are contradictory. In our study, the effect of essential oils obtained from the leaves, flowers, and roots of Myrtus communis L. on oxidative metabolism in an HT model induced by propylthiouracil (PTU) in rats was investigated. A total of 36 Wistar albino rats were randomly divided into six groups as follows: (1) Control, (2) PTU, (3) M. communis L. oil 200 (MO 200), (4) M. communis L. oil 400 (MO 400), (5) PTU + MO 200, and (6) PTU + MO 400. In our study, while oxidative status deteriorates in groups given PTU, antioxidant activity increases in groups given M. communis L. oil. PRACTICAL APPLICATIONS: Essential oils are aromatic oily liquids derived from different parts of plants. M. communis L. is one of the best-known herbs in the class of aromatic and medicinal plants. This paper emphasizes the effect of M. communis L. oil on the negative oxidative state that occurs in HT conditions. The present study provides a positive effect of essential oils obtained from the M. communis L. on the oxidative state seen in HT. In light of this information, it may be beneficial to use M. communis L. oil due to its antioxidative effect in HT conditions.

Thyroid disrupting pesticides mancozeb and fipronil in mixture caused oxidative damage and genotoxicity in lymphoid organs of mice

The interference in endocrine signaling in particular of hypothyroid-pituitary-thyroid axis during embryonic/neonatal development increases the risk of long-lasting immune dysfunctioning. Anticipating that, environmentally realistic exposure of established thyroid disrupting pesticides of dithiocarbamate group mancozeb and phenylpyrazole fipronil was given to mice as individual and as mixtures (MIX-I/MIX-II) during the critical initiation phase of the immune response from postnatal day (PND) 31 till PND 60 (maturation phase). The direct exposure effect was assessed at PND 61 and the persistent effect was assessed at PND 91. Pronounced oxidative stress/genotoxicity in lymphoid organs at even low dose mixture exposure of pesticides (MIX-I/ MIX-II) continued to suppress the immune system till adulthood; might be due to the synergistic/additive action. The oxidative stress/genotoxicity effect was prevented on T4 supplementation to inhibit immunotoxicity as T4 is an immune enhancer and antioxidants. Oxidative stress/genotoxicity is suggested as a mechanism of thyroid disruption mediated immune suppression.

Endoplasmic reticulum stress participates in the pathophysiology of mercury-caused acute kidney injury

Acute exposure to mercury chloride (HgCl₂) causes acute kidney injury (AKI). Some metals interfere with protein folding, leading to endoplasmic reticulum stress (ERS), and the activation of cell death mechanisms, but in the case of mercury, there is no knowledge about whether the ERS mediates tubular damage. This study aimed to determinate if HgCl₂ causes an AKI course with temporary activation of ERS and if this mechanism is involved in kidney cell death. Male mice were intoxicated with 5 mg/kg HgCl₂ and sacrificed after 24, 48, 72, and 96 h of mercury administration. The kidneys of euthanized mice were used to assess the renal function, oxidative stress, redox environment, antioxidant enzymatic system, cell death, and reticulum stress markers (PERK, ATF-6, and IRE1α pathways). The results indicate temporary-dependent renal dysfunction, oxidative stress, and an increase of glutathione-dependent enzymes involved in the bioaccumulation process of mercury, as well as the enhancement of caspase 3 activity along with IRE1a, GADD-153, and caspase 12 expressions. Mercury activates the PERK/eIF2α branch during the first 48 h. Meanwhile, the activation of PERK/ATF-4 branch allowed for ATF-4, ATF-6, and IRE1α pathways to enhance GADD-153. It led to the activation of caspases 12 and 3, which mediated the deaths of the tubular and glomerular cells. This study revealed temporary-dependent ERS present during AKI caused by HgCl₂, as well as how it plays a pivotal role in kidney cell damage.

Dietary-Induced Chronic Hypothyroidism Negatively Affects Rat Follicular Development and Ovulation Rate and Is Associated with Oxidative Stress

The long-term effects of chronic hypothyroidism on ovarian follicular development in adulthood are not well known. Using a rat model of chronic diet-induced hypothyroidism initiated in the fetal period, we investigated the effects of prolonged reduced plasma thyroid hormone concentrations on the ovarian follicular reserve and ovulation rate in prepubertal (12-day-old) and adult (64-day-old and 120-day-old) rats. Besides, antioxidant gene expression, mitochondrial density and the occurrence of oxidative stress were analyzed. Our results show that continuous hypothyroidism results in lower preantral and antral follicle numbers in adulthood, accompanied by a higher percentage of atretic follicles, when compared to euthyroid age-matched controls. Not surprisingly, ovulation rate was lower in the hypothyroid rats. At the age of 120 days, the mRNA and protein content of superoxide dismutase 1 (SOD1) were significantly increased while catalase (CAT) mRNA and protein content was significantly decreased, suggesting a disturbed antioxidant defense capacity of ovarian cells in the hypothyroid animals. This was supported by a significant reduction in the expression of peroxiredoxin 3 ( ITALIC! Prdx3), thioredoxin reductase 1 ( ITALIC! Txnrd1), and uncoupling protein 2 ( ITALIC! Ucp2) and a downward trend in glutathione peroxidase 3 ( ITALIC! Gpx3) and glutathione S-transferase mu 2 ( ITALIC! Gstm2) expression. These changes in gene expression were likely responsible for the increased immunostaining of the oxidative stress marker 4-hydroxynonenal. Together these results suggest that chronic hypothyroidism initiated in the fetal/neonatal period results in a decreased ovulation rate associated with a disturbance of the antioxidant defense system in the ovary.

Thyroid Hormones, Oxidative Stress, and Inflammation

Inflammation and oxidative stress (OS) are closely related processes, as well exemplified in obesity and cardiovascular diseases. OS is also related to hormonal derangement in a reciprocal way. Among the various hormonal influences that operate on the antioxidant balance, thyroid hormones play particularly important roles, since both hyperthyroidism and hypothyroidism have been shown to be associated with OS in animals and humans. In this context, the nonthyroidal illness syndrome (NTIS) that typically manifests as reduced conversion of thyroxine (T₄) to triiodothyronine (T₃) in different acute and chronic systemic conditions is still a debated topic. The pathophysiological mechanisms of this syndrome are reviewed, together with the roles of deiodinases, the enzymes responsible for the conversion of T₄ to T₃, in both physiological and pathological situations. The presence of OS indexes in NTIS supports the hypothesis that it represents a condition of hypothyroidism at the tissue level and not only an adaptive mechanism to diseases.

Protective effects of GM-CSF in experimental neonatal hypothyroidism

Hypothyroidism induced by methimazole (MMI), has a negative impact on the postnatal development. Neonatal Granulocyte Macrophage-Colony Stimulating Factor [GM-CSF; 50μg/kg, intramuscular injection at postnatal day (PND) 17] had been tested to ameliorate the effects of MMI [0.05%, (weight per volume; w/v), intraperitoneal injection at PND 15]-induced hypothyroidism in Wistar rats. The hypothyroid conditions due to the administration of MMI produced inhibitory effects on neonatal serum thyroxine (T4), 3,5,3'-triiodothyronine (T3), neutrophil count in bone marrow and blood, cerebellar glutathione (GSH) and acetylcholinesterase (AchE), although it induced stimulatory actions on serum thyrotropin (TSH), growth hormone (GH), insulin growth factor-II (IGF-II), tumor necrosis factor alpha (TNF-α), and cerebellar malondialdehyde (MDA) at PND 19. The treatment with GM-CSF could reverse the depressing and stimulating effects of MMI on these markers except for cerebellar AchE where its enhancement was non-significant (P>0.05) at tested PND. Thus, neonatal GM-CSF may be responsible for suppressing autoimmune responses and preventing hypothyroidism.

Hypothyroidism minimizes the effects of acute hepatic failure caused by endoplasmic reticulum stress and redox environment alterations in rats

The aim of this study was to investigate if a protective effect from hypothyroidism in acute liver failure resulted from reduced endoplasmic reticulum stress and changes to the redox environment. Twenty male Sprague-Dawley rats were divided in four groups: (1) euthyroid (sham surgery), (2) hypothyroid, (3) euthyroid (sham surgery)+thioacetamide and (4) hypothyroid+thioacetamide. Hypothyroidism was confirmed two weeks after thyroidectomy, and thioacetamide (TAA) (400mg/kg, ip) was administrated to the appropriate groups for three days with supportive therapy. Grades of encephalopathy in all animals were determined using behavioral tests. Animals were decapitated and their blood was obtained to assess liver function. The liver was dissected: the left lobe was used for histology and the right lobe was frozen for biochemical assays. Body weight, rectal temperature and T4 concentration were lower in hypothyroid groups. When measurements of oxidative stress markers, redox environment, γ-glutamylcysteine synthetase and glutathione-S-transferase were determined, we observed that hypothyroid animals with TAA compensated better with oxidative damage than euthyroid animals treated with TAA. Furthermore, we measured reduced expressions of GADD34, caspase-12 and GRP78 and subsequently less hypothyroidism-induced cellular damage in hypothyroid animals. We conclude that hypothyroidism protects against hepatic damage caused by TAA because it reduces endoplasmic reticulum stress and changes to the redox environment.

Vitamin E management of oxidative damage-linked dysfunctions of hyperthyroid tissues

INTRODUCTION

Thyroid hormones affect growth, development, and metabolism of vertebrates, and are considered the major regulators of their homeostasis. On the other hand, elevated circulating levels of thyroid hormones are associated with modifications in the whole organism (weight loss and increased metabolism and temperature) and in several body regions. Indeed, tachycardia, atrial arrhythmias, heart failure, muscle weakness and wasting, bone mass loss, and hepatobiliary complications are commonly found in hyperthyroid animals and humans.

RESULTS

Most thyroid hormone actions result from influences on transcription of T3-responsive genes, which are mediated through nuclear receptors. However, there is significant evidence that tissue oxidative stress underlies some dysfunctions produced by hyperthyroidism.

DISCUSSION

During the last decades, increasing interest has been turned to the use of antioxidants as therapeutic agents in various diseases and pathophysiological disorders believed to be mediated by oxidative stress. In particular, because elevated circulating levels of thyroid hormones are associated with tissue oxidative injury, more attention has been paid to explore the application of antioxidants as therapeutic agents in thyroid related disorders.

CONCLUSIONS

At present, vitamin E is among the most commonly consumed dietary supplements due to the belief that it, as an antioxidant, may attenuate morbidity and mortality. This is due to the results of numerous scientific studies, which demonstrate that vitamin E has a primary function to destroy peroxyl radicals, thus protecting polyunsaturated fatty acids biological membranes from oxidative damage. However, results are also available indicating that protective vitamin E effects against oxidative damage can be obtained even through different mechanisms.

Hypothyroidism maintained reactive oxygen species-steady state in the kidney of rats intoxicated with ethylene glycol: effect related to an increase in the glutathione that maintains the redox environment

Our objective was to determine whether hypothyroidism protects against ethylene glycol (EG)-induced renal damage and whether the redox environment participates in the protection process. We used 36 male Wistar rats divided into four groups: (1) euthyroid, (2) euthyroid + 0.75% EG, (3) hypothyroid, and (4) hypothyroid + 0.75% EG. Hypothyroidism occurred 2 weeks after thyroidectomy. The parathyroid gland was reimplanted. EG was administrated for 21 days in drinking water. On day 21, the renal function was assessed and then the rats were decapitated. The left kidney was processed for histology, and the right kidney was used to determine the redox environment, oxidative stress, and the testing of the antioxidant enzymatic system. EG in euthyroid rats reduced the hydric and electrolytic balance and it also caused oxidative stress and renal damage. Hypothyroidism per se modifies the renal function causing a low osmolal and potassium clearance and the filtered load of potassium and sodium. In addition, there was an enhanced redox state because hypothyroidism increases the reduced glutathione concentration caused by a high activity of γ-glutamylcysteine synthase. Hypothyroidism is a protective state against EG because the changes in the renal function were smaller than in the euthyroid state. The oxidative stress and cellular damage were ameliorated by the hypothyroid condition. Also, the hypothyroidism-enhanced redox environment protects against EG-induced oxidative stress, renal damage, and renal dysfunction.