Attenuation of oxidative stress in plasma and tissues of rats with experimentally induced hyperthyroidism by caffeic acid phenylethyl ester

Lycopene supplementation of maternal and weanling high-fat diets influences adipose tissue development and metabolic outcomes of Sprague-Dawley offspring

Dietary patterns high in fat contribute to the onset of cardiometabolic disease through the accrual of adipose tissue (AT). Lycopene, a carotenoid shown to exert multiple health benefits, may disrupt these metabolic perturbations. The purpose of the present study was to evaluate AT development and obesity-associated metabolic outcomes in the neonate and weanling offspring of Sprague-Dawley mothers fed a high-fat diet (HFD = 50 % fat) with and without lycopene supplementation. Sprague-Dawley rats consumed either a normal fat diet (NFD; 25 % fat) or HFD throughout gestation. Upon delivery, half of HFD mothers were transitioned to an HFD supplemented with 1 % lycopene (HFDL). At postnatal day 14 (P14), P25, and P35, pups were euthanised, body weight was recorded, and visceral white AT (WAT) and brown AT (BAT) mass were determined. Serum redox status, adipokines, glucose and inflammatory biomarkers were evaluated, as well as BAT mRNA expression of uncoupling protein 1 (UCP1). The HFD was effective in inducing weight gain as evident by significantly greater BW and WAT in the HFD group compared to the NFD group across all time points. Compared to HFD, the HFDL group exhibited significantly greater BAT with concomitant reductions in WAT mass, serum lipid peroxides and serum glucose. No significant differences were observed in serum adipokines, inflammatory markers or UCP1 expression despite the aforementioned alterations in AT development. Results suggest that dietary lycopene supplementation may influence metabolic outcomes during the weaning and post-weaning periods. Additional research is warranted to elucidate molecular mechanisms by which lycopene influences AT biology.

Experimental Evidence for Therapeutic Potentials of Propolis

Propolis is produced by honeybees from materials collected from plants they visit. It is a resinous material having mixtures of wax and bee enzymes. Propolis is also known as bee glue and used by bees as a building material in their hives, for blocking holes and cracks, repairing the combs and strengthening their thin borders. It has been extensively used since ancient times for different purposes in traditional human healthcare practices. The quality and composition of propolis depend on its geographic location, climatic zone and local flora. The New Zealand and Brazilian green propolis are the two main kinds that have been extensively studied in recent years. Their bioactive components have been found to possess a variety of therapeutic potentials. It was found that Brazilian green propolis improves the cognitive functions of mild cognitive impairments in patients living at high altitude and protects them from neurodegenerative damage through its antioxidant properties. It possesses artepillin C (ARC) as the key component, also known to possess anticancer potential. The New Zealand propolis contains caffeic acid phenethyl ester (CAPE) as the main bioactive with multiple therapeutic potentials. Our lab performed in vitro and in vivo assays on the extracts prepared from New Zealand and Brazilian propolis and their active ingredients. We provided experimental evidence that these extracts possess anticancer, antistress and hypoxia-modulating activities. Furthermore, their conjugation with γCD proved to be more effective. In the present review, we portray the experimental evidence showing that propolis has the potential to be a candidate drug for different ailments and improve the quality of life.

Vitamin A Supplementation during Suckling and Postweaning Periods Attenuates the Adverse Metabolic Effects of Maternal High-Fat Diet Consumption in Sprague-Dawley Rats

BACKGROUND

Vitamin A (VA) has been demonstrated to be a regulator of adipose tissue (AT) development in adult obese models. However, little is known about the effect of VA on obesity-associated developmental and metabolic conditions in early life.

OBJECTIVES

We aimed to assess the effects of dietary VA supplementation during suckling and postweaning periods on the adiposity and metabolic health of neonatal and weanling rats from mothers consuming a high-fat diet (HFD).

METHODS

Pregnant Sprague-Dawley rats were fed a normal-fat diet (NFD; 25% fat; n = 2) or an HFD (50% fat; n = 2), both with 2.6 mg VA/kg. Upon delivery, half of the rat mothers were switched to diets with supplemented VA at 129 mg/kg, whereas the other half remained at 2.6 mg VA/kg. Four groups of rat pups were designated as NFD, NFD + VA, HFD, and HFD + VA, respectively. At postnatal day (P)14, P25, and P35, pups (n = 4 or 3/group) were killed. Body weight (BW), visceral white AT (WAT) mass, brown AT (BAT) mass, uncoupling protein 1 mRNA expression in BAT, serum glucose, lipids, adipokines, and inflammatory biomarkers, as well as serum and AT redox status were assessed.

RESULTS

Rat pups in the HFD group exhibited significantly higher BW, WAT mass, and serum glucose and leptin but reduced BAT mass compared with the NFD group. Without affecting the dietary intake, supplementing the HFD with VA significantly reduced the BW and WAT mass of pups but increased the BAT mass, significantly lowered the systemic and WAT oxidative stress, and modulated serum adipokines and lipids to some extent.

CONCLUSIONS

VA supplementation during suckling and postweaning periods attenuated metabolic perturbations caused by excessive fat intake. Supplementing maternal or infant obesogenic diets with VA or establishing a higher RDA of VA for specific populations should be studied further for managing overweight/obesity in early life.

Caffeic acid phenethyl ester protects against photothrombotic cortical ischemic injury in mice

In this study, we aimed to investigate the neuroprotective effects of caffeic acid phenethyl ester (CAPE), an active component of propolis purified from honeybee hives, on photothrombotic cortical ischemic injury in mice. Permanent focal ischemia was achieved in the medial frontal and somatosensory cortices of anesthetized male C57BL/6 mice by irradiation of the skull with cold light laser in combination with systemic administration of rose bengal. The animals were treated with CAPE (0.5–5 mg/kg, i.p.) twice 1 and 6 h after ischemic insult. CAPE significantly reduced the infarct size as well as the expression of tumor necrosis factor-α, hypoxiainducible factor-1α, monocyte chemoattractant protein-1, interleukin-1α, and indoleamine 2,3-dioxygenase in the cerebral cortex ipsilateral to the photothrombosis. Moreover, it induced an increase in heme oxygenase-1 immunoreactivity and interleukin-10 expression. These results suggest that CAPE exerts a remarkable neuroprotective effect on ischemic brain injury via its anti-inflammatory properties, thereby providing a benefit to the therapy of cerebral infarction.

Role of Oxidative Stress in Thyroid Hormone-Induced Cardiomyocyte Hypertrophy and Associated Cardiac Dysfunction: An Undisclosed Story

Cardiac hypertrophy is the most documented cardiomyopathy following hyperthyroidism in experimental animals. Thyroid hormone-induced cardiac hypertrophy is described as a relative ventricular hypertrophy that encompasses the whole heart and is linked with contractile abnormalities in both right and left ventricles. The increase in oxidative stress that takes place in experimental hyperthyroidism proposes that reactive oxygen species are key players in the cardiomyopathy frequently reported in this endocrine disorder. The goal of this review is to shed light on the effects of thyroid hormones on the development of oxidative stress in the heart along with the subsequent cellular and molecular changes. In particular, we will review the role of thyroid hormone-induced oxidative stress in the development of cardiomyocyte hypertrophy and associated cardiac dysfunction, as well as the potential effectiveness of antioxidant treatments in attenuating these hyperthyroidism-induced abnormalities in experimental animal models.

Value of caffeic acid phenethyl ester pretreatment in experimental sepsis model in rats

Background and Aim. The aim of this study was to determine the actions of caffeic acid phenethyl ester (CAPE) on the changes of endothelin-1 (ET-1) level, tumor necrosis factor- (TNF-) alpha, and oxidative stress parameters such as superoxide dismutase (SOD) activities and malondialdehyde (MDA) levels in experimental sepsis model in rats. Materials and Methods. Twenty-four rats were randomly divided into three experimental groups: sham (group 1), sepsis (group 2), and sepsis + CAPE (group 3), n = 8 each. CAPE was administered (10 µmol/kg) intraperitoneally to group 3 before sepsis induction. Serum ET-1, serum TNF-alpha, tissue SOD activity, and tissue MDA levels were measured in all groups. Results. Pretreatment with CAPE decreased ET-1, TNF-alpha, and MDA levels in sepsis induced rats. Additionally SOD activities were higher in rats pretreated with CAPE after sepsis induction. Conclusion. Our results demonstrate that CAPE may have a beneficial effect on ET and TNF-alpha levels and oxidative stress parameters induced by sepsis in experimental rat models. Therefore treatment with CAPE can be used to avoid devastating effects of sepsis.

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.

The role of allopurinol on oxidative stress in experimental hyperthyroidism

AIM

During hyperthyroidism, production of free oxygen radicals derives, where xanthine oxidase may also play an important role. Allopurinol, a xanthine oxidase inhibitor, has a significant effect on thyrotoxicosis-related oxidative stress. However, the relationship between thyroid hormones, oxidative stress parameters and allopurinol remains to be explored.

METHODS

Forty-two Wistar albino rats were divided into three groups. Rats in group A served as negative controls, while group B had untreated thyrotoxicosis and group C received allopurinol. Hyperthyroidism was induced by daily 0.2 mg/kg L-thyroxine intraperitoneally in groups B and C; 40 mg/kg allopurinol were given daily intraperitoneally. Efficacy of the treatment was assessed after 72 h and 21 days, by measuring serum xanthine oxidase (XO), malondialdehyde (MDA), glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPx) and nitric oxide derivates (NO*x).

RESULTS

In both time periods, serum XO, MDA, GSH and NO*x levels were significantly increased after thyroid hormone induction (p<0.05). Levels of XO, MDA and NO*x decreased with allopurinol treatment (p<0.05). There was a remarkable decrease in triiodothyronine levels in group C after 72 h (p<0.05), and in both triiodothyronine and thyroxine levels in group C after 21 days (p<0.05). There was no difference between groups B and C in means of serum GSH, GR and GPx levels (p>0.05).

CONCLUSIONS

This study suggests an association between allopurinol and the biosynthesis of thyroid hormones. Allopurinol prevents the hyperthyroid state, which is mediated predominantly by triiodothyronine and not by XO. This issue has to be questioned in further studies where allopurinol is administered in control subjects.

The interaction of oxidative stress response with cytokines in the thyrotoxic rat: is there a link?

Oxidative stress is regarded as a pathogenic factor in hyperthyroidism. Our purpose was to determine the relationship between the oxidative stress and the inflammatory cytokines and to investigate how melatonin affects oxidative damage and cytokine response in thyrotoxic rats. Twenty-one rats were divided into three groups. Group A served as negative controls. Group B had untreated thyrotoxicosis, and Group C received melatonin. Serum malondialdehyde (MDA), glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPx), and nitric oxide derivates (NO^•x), and plasma IL-6, IL-10, and TNF-alpha were measured. MDA, GSH, NO^•x, IL-10, and TNF-alpha levels increased after L-thyroxine induction. An inhibition of triiodothyronine and thyroxine was detected, as a result of melatonin administration. MDA, GSH, and NO^•x levels were also affected by melatonin. Lowest TNF-alpha levels were observed in Group C. This study demonstrates that oxidative stress is related to cytokine response in the thyrotoxic rat. Melatonin treatment suppresses the hyperthyroidism-induced oxidative damage as well as TNF-alpha response.