Effects of altered thyroid states on oxidative stress parameters in rats

SGLT2 inhibitor as a potential therapeutic approach in hyperthyroidism-induced cardiopulmonary injury in rats

Hyperthyroidism-induced cardiac disease is an evolving health, economic, and social problem affecting well-being. Sodium-glucose cotransporter protein 2 inhibitors (SGLT2-I) have been proven to be cardio-protective when administered in cases of heart failure. This study intended to investigate the potential therapeutic effect of SGLT2-I on hyperthyroidism-related cardiopulmonary injury, targeting the possible underlying mechanisms. The impact of the SGLT2-I, dapagliflozin (DAPA), (1 mg/kg/day, p.o) on LT4 (0.3 mg/kg/day, i.p)-induced cardiopulmonary injury was investigated in rats. The body weight, ECG, and serum hormones were evaluated. Also, redox balance, DNA fragmentation, inflammatory cytokines, and PCR quantification in heart and lung tissues were employed to investigate the effect of DAPA in experimentally induced hyperthyroid rats along with histological and immunohistochemical examination. Coadministration of DAPA with LT4 effectively restored all serum biomarkers to nearly average levels, improved ECG findings, and reinstated the redox balance. Also, DAPA could improve DNA fragmentation, elevate mtTFA, and lessen TNF-α and IGF-1 gene expression in both organs of treated animals. Furthermore, DAPA markedly improved the necro-inflammatory and fibrotic cardiopulmonary histological alterations and reduced the tissue immunohistochemical expression of TNF-α and caspase-3. Although further clinical and deep molecular studies are required before transposing to humans, our study emphasized DAPA's potential to relieve hyperthyroidism-induced cardiopulmonary injury in rats through its antioxidant, anti-inflammatory, and anti-apoptotic effects, as well as via antagonizing the sympathetic over activity.

Dietary Supplementation of Chestnut Tannins in Prepartum Dairy Cows Improves Antioxidant Defense Mechanisms Interacting with Thyroid Status

Cows in the peripartal period undergo changes in thyroid hormones and are susceptible to lipomobilization and/or oxidative stress. The addition of chestnut tannins as polyphenolic compounds in the diet may improve feed efficiency and prevent oxidative stress-related health disorders in transition cows. However, the relationship between chestnut tannin supplementation and thyroid function, which plays an important role in metabolic regulation, has not been investigated in dairy cows. This study was conducted to investigate the effects of chestnut tannin supplementation during the close-up period on thyroid status and to evaluate the interaction between thyroid hormones and oxidative stress biomarkers in prepartum dairy cows. Forty multiparous Holstein cows were fed either a diet containing chestnut tannins (CNTs, n = 20, 1.96 g chestnut tannins/kg feed, dry matter) or a non-supplemented diet (CON, n = 20) during the last 25 ± 2 days of gestation. Blood samples were collected on the first day of study (before chestnut tannin supplementation) and d 5 before parturition to measure hormonal and oxidative stress indices. Serum concentrations of T3 (p = 0.04) and T4 (p = 0.05) were higher in CNT cows than in the CON group on day 5 before parturition. Thyroid status of CNT cows was associated with higher serum total antioxidant capacity (T-AOC, p < 0.01), activities of superoxide dismutase (SOD, p = 0.03) and glutathione peroxidase (GPx, p = 0.01), and reduced glutathione concentration (GSH, p = 0.05). Serum thiobarbituric acid reactive substances (TBARS) were lower (p = 0.04) which was associated with lower aspartate aminotransferase (AST, p = 0.02), and lactate dehydrogenase (LDH, p = 0.01) activities in the CNT than in the CON group. Estradiol and progesterone did not differ between CNT and CON cows. Chestnut tannin supplementation improves antioxidant protection, prevents oxidation-reduction processes, reduces the degree of liver cell membrane damage, and protects thyroid tissue from damage, allowing higher T3 and T4 synthesis. Considering the importance of the thyroid hormone status before parturition, mechanisms of thyroid hormone regulation in CNT-supplemented dairy cows require more detailed investigations.

The management and metabolic characterization: hyperthyroidism and hypothyroidism

Hyperthyroidism and hypothyroidism are common diseases resulting from thyroid dysfunction, and are simple to diagnose and treat. The traditional treatment for hypothyroidism is thyroid hormone replacement therapy. The traditional treatments for hyperthyroidism include antithyroid drug, iodine radiotherapy, and surgery. Thyroid disease can be fatal in severe cases if untreated. Current statistical reference ranges used for diagnosis based on relevant biochemical parameters have been debated, and insufficient treatment can result in long-term thyroid hormone deficiency, which is associated with increased risk of cardiovascular disease and persistent symptoms. In contrast, overtreatment can result in heart disease and osteoporosis, particularly in older people and pregnant women. Therefore, under- or over-treatment should be avoided and treatment regimens should be monitored closely. A significant proportion of patients who achieve biochemical treatment goals still complain of significant symptoms. Systematic literature review was performed through the Embase (Elsevier), PubMed and Web of Science databases, and studies summarized evidence regarding treatment and management of hypothyroidism and hyperthyroidism, and reviewed clinical practice guidelines. We also reviewed the latest research on the metabolic mechanisms of hyperthyroidism and hypothyroidism, which contributed to understanding of thyroid diseases in the clinic. A reliable algorithm is needed to management, assessment, and treatment patients with hyperthyroidism and hypothyroidism, which can not only improve management efficiency, but also providing a broad application. In addition, the thyroid disorder showed a lipid metabolism tissue specificity in the Ventromedial Hypothalamus, and effect oxidative stress and energy metabolism of whole body. This review summarizes an algorithm for thyroid disease and the latest pathogenesis that would be useful to generalist and subspecialty physicians and others providing care for patients with this condition.

Protective role of vitamin D3 in a rat model of hyperthyroid-induced cardiomyopathy

Background and aim

Several studies have reported the cardioprotective effect of vitamin D. Thus, this study aimed to investigate the possible cardioprotective effect of vitamin D3 in hyperthyroid-induced cardiomyopathy rat model.

Experimental procedure

Rats were divided into 3 groups: control group; hyperthyroid group, rats were administrated l-thyroxine sodium daily for 4 weeks; and hyperthyroid + vitamin D3 treated group, rats were treated with l-thyroxine sodium for 4 weeks daily, and received the vitamin D3 for the same duration. After 4 weeks, electrocardiogram (ECG) was recorded. Then, blood samples were collected for biochemical analysis. After that, the final body weight was measured, and the rats were sacrificed. Finally, the hearts were excised, weighed and were prepared for histological examination by hematoxylin and eosin, and immunohistochemistry assessment of caspase-3 and proliferating cell nuclear antigen (PCNA).

Results

Hyperthyroid rats showed significant ECG changes, increased serum levels of cardiac biomarkers, fibroblast growth factor-23 (FGF23), malondialdehyde, antioxidant enzymes, tumor necrosis factor-alpha (TNF-α) and relative heart weight compared with the control rats. Vitamin D3 coadministration with l-thyroxine resulted in significant improvement in thyroid profile, ECG parameters, significant decrease of cardiac biomarkers, FGF23, malondialdehyde, TNF-α and relative heart weight, and significant decrease of the antioxidant enzymes compared with the hyperthyroid rats. The histological study was consistent with the biochemical results. Hyperthyroid rats showed upregulation of caspase-3 and PCNA in the myocardium compared with control group. Vitamin D3 treated rats showed downregulation of caspase-3 and PCNA.

Conclusion

Vitamin D3 provides cardioprotective effects in hyperthyroid rats.

The effects of curcumin in learning and memory impairment associated with hypothyroidism in juvenile rats: the role of nitric oxide, oxidative stress, and brain-derived neurotrophic factor

The effect of curcumin (Cur) on cognitive impairment and the possible role of brain tissue oxidative stress, nitric oxide (NO) levels, and brain-derived neurotrophic factor (BDNF) were investigated in juvenile hypothyroid rats. The juvenile rats (21 days old) were allocated into the following groups: (1) control; (2) hypothyroid (0.05% propylthiouracil (PTU) in drinking water); (3-5) hypothyroid-Cur 50, 100, and 150, which in these groups 50, 100, or 150 mg/kg, Cur was orally administered by gavage during 6 weeks. In the hypothyroid rats, the time elapsed and the traveled distance to locate the hidden platform in the learning trials of Morris water maze (MWM) increased, and on the probe day, the amount of time spent in the target quadrant and the distance traveled in there was decreased. Hypothyroidism also decreased the latency and increased the time spent in the darkroom of the passive avoidance (PA) test. Compared with the hypothyroid group, Cur enhanced the performance of the rats in both MWM and PA tests. In addition, Cur reduced malondialdehyde concentration and NO metabolites; however, it increased thiol content as well as the activity of catalase (CAT) and superoxide dismutase enzymes in both the cortex and hippocampus. Cur also increased hippocampal synthesis of BDNF in hypothyroid rats. The beneficial effects of Cur cognitive function in juvenile hypothyroid rats might be attributed to its protective effect against oxidative stress and potentiation of BDNF production.

Essentiality, relevance, and efficacy of adjuvant/combinational therapy in the management of thyroid dysfunctions

Thyroid dysfunction is the most prevalent endocrine disorder worldwide having an epidemiology of 11% in Indians, 4.6% in the United Kingdom, and 2% in the United States of America among the overall population. The common thyroid disorders include hypothyroidism, hyperthyroidism, Hashimoto's thyroiditis, and thyroid cancer. This review briefly elaborates the molecular regulation and mechanism of thyroid hormone, and its associated thyroid disorders. The thyroid hormones regulate critical biochemical functions in brain development and function. Hypothyroidism is mainly associated with dysregulation of cytokines, increased ROS production, and altered signal transduction in major regions of the brain. In addition, it is associated with reduced antioxidant capacity and increased oxidative stress in humans. Though 70% of thyroid disorders are caused by heredity, environmental factors have a significant influence in developing autoimmune thyroid disorders in people who are predisposed to them. This drives us to understand the relationship between environmental factors and thyroid dysregulated disorders. The treatment option for the thyroid disorder includes antithyroid medications, receiving radioactive iodine therapy, or surgery at a critical stage. However, antithyroid drugs are not typically used long-term in thyroid disease due to the high recurrence rate. Adjuvant treatment of antioxidants can produce better outcomes with anti-thyroid drug treatment. Thus, Adjuvant therapy has been proven as an effective strategy for managing thyroid dysfunction, herbal remedies can be used to treat thyroid dysfunction in the future, which in turn can reduce the prevalence of thyroid disorders.

Oxidative Stress Parameters in Goitrogen-Exposed Crested Newt Larvae (Triturus spp.): Arrested Metamorphosis

Thiourea is an established disruptor of thyroid hormone synthesis and is frequently used as an inhibitor of metamorphosis. The changes caused by thiourea can affect processes associated with the oxidative status of individuals (metabolic rate, the HPI axis, antioxidant system). We investigated the parameters of oxidative stress in crested newt (Triturus spp.) larvae during normal development in late larval stage 62 and newly metamorphosed individuals, and during thiourea-stimulated metamorphosis arrest in individuals exposed to low (0.05%) and high (0.1%) concentrations of thiourea. Both groups of crested newts exposed to thiourea retained their larval characteristics until the end of the experiment. The low activities of antioxidant enzymes and the high lipid peroxidation level pointed to increased oxidative stress in larvae at the beginning of stage 62 as compared to fully metamorphosed individuals. The activities of catalase (CAT) and glutathione-S-transferase (GST) and the concentration of sulfhydryl (SH) groups were significantly lower in larvae reared in aqueous solutions containing thiourea than in newly metamorphosed individuals. The high thiourea concentration (0.1%) affected the antioxidative parameters to the extent that oxidative damage could not be avoided, contrary to a lower concentration. Our results provide a first insight into the physiological adaptations of crested newts during normal development and simulated metamorphosis arrest.

Effect of thiamazole on kainic acid-induced seizures in mice

Kainic acid (KA) induced epileptic seizures in mice is a commonly used experimental model of epilepsy. Previous studies have suggested the roles of various neurotransmitters and oxidative stress in KA-induced seizures. An important role of hypothyroidism has also been suggested in epilepsy. Thiamazole (TZ) is an anti-hyperthyroid drug with antioxidant property. This study reports the effect of TZ on KA-induced epileptic seizures in mice, produced by intraperitoneal (IP) injection of KA (18 mg/kg). Prior to KA injection, the animals were treated with TZ (12.5, 25 and 50 mg/kg IP). Our results showed that in KA alone group, about half of the animals developed seizures. Pre-treatment of mice with TZ significantly increased the frequency of seizures in dose-dependent manner. Administration of TZ significantly reduced the latency time and aggravated the severity of seizures. TZ also increased the mortality in KA-treated mice. Striatal dopamine and serotonin levels were markedly increased in KA alone treated mice, which were not significantly affected by TZ treatment. Among the indices of oxidative stress, we observed a significant reduction in cerebral vitamin E whereas the levels of cerebral malondialdehyde and conjugated dienes were significantly increased in animals with high severity of seizures. In conclusion, TZ potentiated the frequency and severity of experimental seizure in mice. There is a possibility of altered metabolism of KA in presence of TZ that might have potentiated the toxicity of KA. These findings suggest a caution while administering anti-hyperthyroid drugs in epileptic seizures.

Association Between Thyroid Diseases and Parkinson's Disease: A Nested Case-Control Study Using a National Health Screening Cohort

BACKGROUND

Although the dopaminergic system is interconnected with the hypothalamic-pituitary-thyroid axis, few studies have explained the causal relationship between thyroid disease and Parkinson's disease (PD).

OBJECTIVE

The goal of this study was to investigate the association between thyroid diseases and PD in Korean residents.

METHODS

The Korean National Health Insurance Service-National Sample Cohort, which includes individuals aged ≥40 years, was assessed from 2002 to 2015. A total of 5,586 PD patients were matched by age, sex, income, and the region of residence with 22,344 control participants at a ratio of 1:4. In the PD and control groups, previous histories of levothyroxine treatment, goiter, hypothyroidism, thyroiditis, and hyperthyroidism were investigated.

RESULTS

The rates of levothyroxine treatment for more than 3 months, hypothyroidism, and hyperthyroidism were higher in the PD group than the control group (3.2%, 3.8%, and 2.8% vs. 2.5%, 2.9%, and 1.9%, respectively, p < 0.05). The adjusted odds ratios (ORs) in model 2, which was adjusted for all potential confounders, for hypothyroidism and hyperthyroidism in the PD group were 1.25 (95% confidence interval (CI) 1.01-1.55, p = 0.044) and 1.37 (95% CI 1.13-1.67, p = 0.002), respectively. In subgroup analyses, the association between hypothyroidism and PD was maintained in men older than 70 years and the association between hyperthyroidism and PD was maintained in women younger than 70 years.

CONCLUSION

Both hyperthyroidism and hypothyroidism were associated with higher risk of PD, particularly for women younger than 70 years and men older than 70 years, respectively.

α-Lipoic Acid Ameliorates The Changes in Prooxidant-Antioxidant Balance in Liver and Brain Tissues of Propylthiouracil-Induced Hypothyroid Rats

Objective

There are controversial data about the prooxidant-antioxidant balance in hypothyroidism. We aimed to investigate the effect of α-lipoic acid (ALA) on oxidative stress parameters in the liver and brain of propylthiouracil (PTU)-induced hypothyroid rats.

Materials and Methods

In this experimental study, PTU (500 mg/L) was given to rats in drinking water for 10 weeks. ALA (0.2% in diet) alone and together with thyroxine (T4, 20 µg/kg body weight, s.c) were given to hypothyroid rats in the last 5 weeks of the experimental period. The levels of reactive oxygen species, malondialdehyde, protein carbonyl, ferric reducing antioxidant power (FRAP) and glutathione (GSH) levels, superoxide dismutase, and GSH peroxidase activities were determined in the liver and brain of rats. Histopathological examinations were also performed.

Results

Prooxidant parameters were increased in the brain but not liver in hypothyroid rats. ALA treatment alone lowered enhanced brain oxidative stress in hypothyroid rats. Also, ALA was found to ameliorate the changes as a result of oxidative stress arising from T4 replacement therapy.

Conclusion

Our results indicate that ALA alone and together with T4 may be useful in reducing oxidative stress in thyroid dysfunctions.

Consequences on aging process and human wellness of generation of nitrogen and oxygen species during strenuous exercise

Impairment of antioxidant defense system and increase in metabolic rate and production of reactive oxygen species have been demonstrated in strenuous exercise. Both at rest and during contractile activity, skeletal muscle generates a very complex set of reactive nitrogen and oxygen species; the main generated are superoxide and nitric oxide. The nature of the contractile activity influences the pattern and the magnitude of this reactive oxygen and nitrogen species (ROS) generation. The intracellular pro-oxidant/antioxidant homeostasis undergoes alteration owing to strenuous exercise and the major identified sources of intracellular free radical generation during physical activity are the mitochondrial electron transport chain, polymorphoneutrophil, and xanthine oxidase. Reactive oxygen species increased tissue susceptibility to oxidative damage and pose a serious threat to the cellular antioxidant defense system. The possible dangerous consequences of the aging process and human wellness are emphasized in this review.

Do Different Species of Sargassum in Haizao Yuhu Decoction Cause Different Effects in a Rat Goiter Model?

Sargassum species combined with Glycyrrhiza uralensis is a famous herbal pair in traditional Chinese medicine, as one of the so-called “eighteen antagonistic medicaments.” In the Chinese Pharmacopoeia, two different species of Sargassum, Sargassum pallidum and Sargassum fusiforme, are recorded but they are not clearly differentiated in clinical use. In this study, we aimed to determine whether the two species of Sargassum could result in different effects when combined with G. uralensis in Haizao Yuhu Decoction (HYD), which is used for treating thyroid-related diseases, especially goiter. HYD containing S. pallidum or S. fusiforme was administered to rats with propylthiouracil-induced goiter. After 4 weeks, pathological changes in the thyroid tissue and the relative thyroid weight indicated that HYD containing S. pallidum or S. fusiforme protected thyroid tissues from propylthiouracil damage. Neither species increased the propylthiouracil-induced decrease in serum levels of thyroid hormones. However, there were some differences in their actions, and only HYD containing S. fusiforme abated the propylthiouracil-induced elevation of serum thyroid-stimulating hormone levels and activated thyroglobulin mRNA expression.

Chavibetol corrects thyrotoxicosis through alterations in thyroid peroxidase

Thyrotoxicosis is a clinical syndrome that commonly results from excess secretion and/or release of thyroid hormones in the circulation. It affects most of the body systems and if not treated properly may lead to serious health problems. In this investigation, we isolated a phenolic compound, chavibetol (CHV) from Piper betel leaf and evaluated its possible ameliorative effects in thyrotoxicosis of rats. Adult female rats were rendered thyrotoxic by the administration of L-thyroxine (L-T₄) at 500 μg/kg/day, i.p., for 12 days, and then chavibetol (20.0 mg/kg, p.o.) was administered for 2 weeks. L-T₄ administration elevated the concentration of serum thyroxine and triiodothyronine, activities of alanineaminotransferase and aspartate aminotransferase, and decreased the thyrotropin level as well as the expression of thyroid peroxidase (TPO). Further, it increased the activities of hepatic 5'mono-deiodinase-I, glucose-6--phosphatase, sodium-potasium-ATPase, and lipid peroxidation, and depleted the cellular antioxidants. However, chavibetol treatment to thyrotoxic rats normalized almost all these indices including TPO and also preserved the integrity of thyroid tissues suggesting its potential to correct thyrotoxicosis. Effects of CHV were more or less similar to a conventional antithyroid drug, propylthiouracil (PTU).

Nano-diamino-tetrac (NDAT) inhibits PD-L1 expression which is essential for proliferation in oral cancer cells

Programmed death-ligand 1 (PD-L1) is a critical regulator to defend tumor cells against immune surveillance. Thyroid hormone has been shown to induce PD-L1 expression in cancer cells. Its nano-particulated analogue, nano-diamino-tetrac (NDAT; Nanotetrac) is an anticancer/anti-angiogenic agent. In the current study, the inhibitory mechanism by which NDAT inhibited PD-L1 mRNA abundance and PD-L1 protein content in oral cancer cells was investigated. NDAT inhibited inducible PD-L1 expression and protein accumulation by the inhibition of activated ERK1/2 and PI3K. Knockdown PD-L1 also inhibited the proliferation of oral cancer cells which suggests that the inhibitory effect of NDAT on PD-L1 expression maybe is one of the critical mechanisms for NDAT-induced anti-proliferative effect in oral cancer cells.

Thyroid hormones affect nitrergic innervation function in rat mesenteric artery: Role of the PI3K/AKT pathway

We aimed to determine the influence of nitrergic innervation function on the decreased mesenteric arterial tone induced by high levels of triiodothyronine (T3), as a model of acute thyroiditis, as well as the mechanism/s implicated. We analysed in mesenteric segments from male Wistar rats the effect of 10 nmol/L T3 (2 h) on the vasomotor response to electrical field stimulation (EFS) in the presence/absence of specific neuronal NOS (nNOS) inhibitor L-NPA, or superoxide anion scavenger tempol. Nitric oxide (NO) release was measured in the presence/absence of tempol or PI3K inhibitor LY294002. Superoxide anion and peroxynitrite releases, nNOS, PI3K, AKT and superoxide dismutase (SOD) 1 and 2 expressions, nNOS and AKT phosphorylation, and SOD activity were analysed. T3 decreased EFS-induced vasoconstriction. L-NPA increased EFS-induced vasoconstriction more markedly in T3-incubated segments. T3 increased NO release. Tempol decreased EFS-induced vasoconstriction and augmented NO release only in segments without T3. LY294002 decreased NO release in T3-incubated segments. T3 diminished superoxide anion and peroxynitrite formation, enhanced SOD-2 expression, nNOS and AKT phosphorylations and SOD activity, and did not modify nNOS, PI3K, AKT and SOD-1 expressions. In conclusion, these results show a compensatory mechanism aimed at reducing the enhanced blood pressure that appears during acute thyroiditis.