Propylthiouracil (PTU)-induced hypothyroidism alleviates burn-induced multiple organ injury

A Fine Regulation of the Hippocampal Thyroid Signalling Pro-Tects Hypothyroid Mice against Glial Cell Activation

Adult-onset hypothyroidism is associated with learning and cognitive dysfunctions, which may be related to alterations in synaptic plasticity. Local reduced levels of thyroid hormones (THs) may impair glia morphology and activity, and promote the increase of pro-inflammatory cytokine levels mainly in the hippocampus. Given that neuroinflammation induces memory impairments, hypothyroidism-related glia dysfunction may participate in brain disorders. Thus, we investigated the mechanisms linking hypothyroidism and neuroinflammation, from a protective perspective. We induced hypothyroidism in adult C57BL/6J and wild-derived WSB/EiJ male mice by a seven-week propylthiouracil (PTU) treatment. We previously showed that WSB/EiJ mice were resistant to high-fat diet (HFD)-induced obesity, showing no neuroinflammatory response through adaptive abilities, unlike C57BL/6J. As PTU and HFD treatments are known to induce comparable inflammatory responses, we hypothesized that WSB/EiJ mice might also be protected against hypothyroidism-induced neuroinflammation. We showed that hypothyroid WSB/EiJ mice depicted no hippocampal neuroinflammatory response and were able to maintain their hippocampal thyroid signalling despite low circulatisng TH levels. In contrast, C57BL/6J mice exhibited disturbed hippocampal TH signalling, accompanied by neuroinflammation and memory impairment. Our results reinforce the preponderance of the hippocampal TH regulatory system over TH circulating levels in the hippocampal glial reactivity.

Xiao-Luo-Wan treats propylthiouracil-induced goiter with hypothyroidism in rats through the PI3K-AKT/RAS pathways based on UPLC/MS and network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Goiter with hypothyroidism occurs in several thyroid diseases. Xiao-Luo-Wan (XLW), which contains Scrophularia ningpoensis Hemsl., Fritillaria thunbergii Miq. and Ostrea gigas Thunberg, has been used as an effective Chinese medicine for the treatment of goiters in China for hundreds of years. Based on clinical observations and experimental studies, XLW also exerts a certain effect on hypothyroidism. However, the therapeutic mechanism of XLW remains unclear.

AIM OF THE STUDY

The present study aimed to investigate the therapeutic effect of XLW on propylthiouracil (PTU)-induced goiter with hypothyroidism in rats and to uncover the underlying molecular mechanism using ultra high-performance liquid chromatography-mass spectrometry (UPLC/MS), network pharmacology, and molecular docking simulations.

MATERIALS AND METHODS

After successful modeling, the remaining rats were randomly divided into a model group, an Euthyrox group, an XLW group, and a control group. The corresponding drugs were given by gavage for four consecutive weeks. The growth status was monitored, the relative thyroid weight was calculated, and the total serum T3, T4, and TSH content were detected. Hematoxylin-eosin (H&E) staining was used to observe the pathological changes in the thyroid glands. The chemical components of the XLW were identified by UPLC/MS and the putative targets of XLW were predicted using multiple databases. We performed network pharmacology based on the intersection of goiter/hypothyroidism-related targets and XLW targets. Then, we performed KEGG pathway enrichment analysis, and key targets were further screened using protein-protein interaction (PPI) networks. Finally, molecular docking was used to predict the binding ability of XLW identified components and the key targets.

RESULTS

XLW significantly increased the levels of T3 and T4, and reduced TSH, increased body weight, and decreased swollen thyroid glands in PTU-induced rats. XLW promoted the morphological recovery of thyroid follicles and epithelial cells. Twenty-one main chemical components of XLW were identified using UPLC/MS. 270 potential gene targets of XLW and 717 known targets of goiter/hypothyroidism disease were obtained by searching the Traditional Chinese Medicine Systems Pharmacology Database (TCMSP), Swiss Target Prediction, and UniProt databases. A total of 83 KEGG pathways were enriched with phosphatidylinositol 3-kinase-protein kinase B (PI3K-AKT) and RAS signaling pathways. PPI analysis revealed nine key targets of kinase-protein kinase B (AKT) 1, interleukin (IL) 6, vascular endothelial growth factor A (VEGFA), tumor necrosis factor (TNF), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), epidermal growth factor receptor (EGFR), GTPase HRas (HRAS), matrix metalloproteinase (MMP) 9, and heat shock protein 90 alpha family class A member 1 (HSP90AA1). Molecular docking verified which drug components had good binding ability to key targets (all ≤5 kcal/mol).

CONCLUSION

For PTU-induced goiter with hypothyroidism in rats, XLW improves thyroid function, reduces goiter, increases body weight, and promotes the recovery of thyroid follicles and epithelial cells. The underlying molecular mechanism suggests that XLW may regulate thyroid hormone signaling by regulating the PI3K-AKT, RAS, and other signaling pathways. This study provides a pharmacological and biological basis for using XLW to treat goiter with hypothyroidism.

Dynorphins in Development and Disease: Implications for Cardiovascular Disease

It is well-established that cardiovascular disease continues to represent a growing health problem and significant effort has been made to elucidate the underlying mechanisms. In this review, we report on past and recent high impact publications in the field of intracrine network signaling, focusing specifically on opioids and their interrelation with key modulators of the cardiovascular system and the onset of related disease. We present an overview of studies outlining the scope of cardiovascular and cerebrovascular processes that are affected by opioids, including heart function, ischemia, reperfusion, and blood flow. Specific emphasis is placed on the importance of dynorphin molecules in cerebrovascular and cardiovascular regulation. Evidence suggests that excessive or insufficient dynorphin could make an important contribution to cardiovascular physiology, yet numerous paradoxical observations frequently impede a clear understanding of the role of dynorphin. Thus, we argue that dynorphin-mediated signaling events for which an immediate regulatory effect is disputed should not be dismissed as unimportant, as they may play a role in cross-talk with other signaling networks. Finally, we consider the most recent evidence on the role of dynorphin during cardiovascular-related inflammation and on the potential value of endogenous and exogenous inhibitors of kappa-opioid receptor, a major dynorphin A receptor, to limit or prevent cardiovascular disease and its related sequelae.

Effects of burns on gut motor and mucosa functions

This review analyzed the published studies on the effects of thermal injury on gastrointestinal motility and mucosal damage. Our strategy was to integrate all available evidence to provide a complete review on the prokinetic properties of variable reagents and the potential clinical treatment of mucosal damage and gastrointestinal dysmotility after thermal injury. We classified the studies into two major groups: studies on gastrointestinal dysmotility and studies on mucosal damage. We also subclassified the studies into 3 parts: stomach, small intestine, and colon. This review shows evidence that ghrelin can recover burn-induced delay in gastric emptying and small intestinal transit, and can protect the gastric mucosa from burn-induced injury. Oxytocin and β-glucan reduced the serum inflammatory mediators, and histological change and mucosal damage indicators, but did not show evidence of having the ability to recover gastrointestinal motility. Using a combination of different reagents to protect the gastrointestinal mucosa against damage and to recover gastrointestinal motility is an alternative treatment for thermal injury.

Burn-Induced Multiple Organ Injury and Protective Effect of Lutein in Rats

Thermal injury may lead to multiple organ dysfunction through release of proinflammatory mediators and reactive oxygen radicals. This study investigated the effects of thermal injury on remote organs of rats and the possible protective effect of lutein. Thermal trauma was induced in the back of rats by exposing them to 90 °C bath for 10 s. Rats were sacrificed 48 h after burn, and blood samples were collected to monitor liver and kidney functions. Tissue samples from liver, kidneys, and lungs were taken for studying oxidative stress parameters, gene expressions of TNF-α and Casp-3, besides histopathological examination. Skin scald injury caused significant elevations of liver and kidney function biomarkers in the serum. In tissue samples, increments of MDA, GPx, and 8-OHdG were recorded while GSH level and the activities of CAT and SOD were suppressed. The expressions of TNF-α and caspase-3 mRNA were increased, and histopathological results revealed remote organ injury. Oral administration of lutein (250 mg/kg) resulted in amelioration of the biochemical and molecular changes induced by burn as well as the histopathological alterations. According to the findings of the present study, lutein possesses anti-oxidant, anti-inflammatory, and anti-apoptotic effects that protect against burn-induced damage in remote organs.

Effects of thyroid hormones on the antioxidative status in the uterus of young adult rats

Thyroid hormones and oxidative stress play significant roles in the normal functioning of the female reproductive system. Nitric oxide (NO), a free radical synthesized by nitric oxide synthases (NOS), participates in the regulation of thyroid function and is also a good biomarker for assessment of the oxidative stress status. Therefore, the purpose of this study was to investigate effects of thyroid hormones on uterine antioxidative status in young adult rats. Thirty immature female Sprague-Dawley rats were randomly divided into three groups: control, hypothyroid (hypo-T) and hyperthyroid (hyper-T). The results showed the body weights decreased significantly in both the hypo-T and hyper-T groups and that uterine weights were decreased significantly in the hypo-T group. The serum concentrations of total triiodothyronine (T3) and thyroxine (T4), as well as estradiol (E2), were significantly decreased in the hypo-T group, but increased in the hyper-T group. The progesterone (P4) concentrations in the hypo- and hyperthyroid rats markedly decreased. Immunohistochemistry results provided evidence that thyroid hormone nuclear receptor α/β (TRα/β) and three NOS isoforms were located in different cell types of rat uteri. The NO content and total NOS and inducible NOS (iNOS) activities were markedly diminished in the hypo-T group but increased in the hyper-T group. Moreover, the activities of both glutathione peroxidase (GSH-Px) and catalase (CAT) exhibited significant decreases and increases in the hypo-T and hyper-T groups, respectively. The malondialdehyde (MDA) contents in both the hypo-T and hyper-T groups showed a significant increase. Total superoxide dismutase (T-SOD) activity in the hypo- and hyper-T rats markedly decreased. In conclusion, these results indicated that thyroid hormones have an important influence on the modulation of uterine antioxidative status.

The protective effect of propylthiouracil against hepatotoxicity induced by chromium in adult mice

Environmental and occupational exposure to chromium compounds, especially hexavalent chromium (Cr(VI)), is widely recognized as potentially hepatotoxic in humans and animals. Its toxicity is associated with overproduction of free radicals, which induces oxidative damage. This study focused on the possible protective effect of propylthiouracil (PTU) against potassium dichromate (K2Cr2O7). Female mice were divided into four groups (groups I–IV) with seven animals in each group. Group I served as a control, which received tap water; group II received K2Cr2O7 alone (75 mg kg−1 body weight (b.w.)) via drinking water; group III received both K2Cr2O7 via drinking water and PTU by intramuscular injection at a dose 2.5 mg/100 g−1 b.w. twice a week, and group IV received PTU alone twice a week for 30 days. Exposure of mice to Cr promoted oxidative stress with an increase in malondialdehyde, protein carbonyl, and advanced oxidation protein product levels. Nonenzymatic antioxidants such as glutathione, nonprotein thiol, vitamin C levels and enzymatic antioxidant activities such as glutathione peroxidase and superoxide dismutase were decreased, while catalase activity was increased. Biomarkers of liver injury such as aspartate and alanine transaminases, lactate dehydrogenase activities, bilirubin, albumin, and glucose levels were increased, while triglyceride and cholesterol levels decreased. Coadministration of PTU restored the above-mentioned parameters to near-normal values. The histological findings confirmed the biochemical results.

Propylthiouracil prevents cutaneous and pulmonary fibrosis in the reactive oxygen species murine model of systemic sclerosis

INTRODUCTION

Recent advances suggest that the cellular redox state may play a significant role in the progression of fibrosis in systemic sclerosis (SSc). Another, and as yet poorly accounted for, feature of SSc is its overlap with thyroid abnormalities. Previous reports demonstrate that hypothyroidism reduces oxidant stress. The aim of this study was therefore to evaluate the effect of propylthiouracil (PTU), and of the hypothyroidism induced by it, on the development of cutaneous and pulmonary fibrosis in the oxidant stress murine model of SSc.

METHODS

Chronic oxidant stress SSc was induced in BALB/c mice by daily subcutaneous injections of hypochlorous acid (HOCl) for 6 weeks. Mice (n = 25) were randomized into three arms: HOCl (n = 10), HOCl plus PTU (n = 10) or vehicle alone (n = 5). PTU administration was initiated 30 minutes after HOCl subcutaneous injection and continued daily for 6 weeks. Skin and lung fibrosis were evaluated by histologic methods. Immunohistochemical staining for alpha-smooth muscle actin (α-SMA) in cutaneous and pulmonary tissues was performed to evaluate myofibroblast differentiation. Lung and skin concentrations of vascular endothelial growth factor (VEGF), extracellular signal-related kinase (ERK), rat sarcoma protein (Ras), Ras homolog gene family (Rho), and transforming growth factor (TGF) β were analyzed by Western blot.

RESULTS

Injections of HOCl induced cutaneous and lung fibrosis in BALB/c mice. PTU treatment prevented both dermal and pulmonary fibrosis. Myofibroblast differentiation was also inhibited by PTU in the skin and lung. The increase in cutaneous and pulmonary expression of VEGF, ERK, Ras, and Rho in mice treated with HOCl was significantly prevented in mice co-administered with PTU.

CONCLUSIONS

PTU, probably through its direct effect on reactive oxygen species or indirectly through thyroid function inhibition, prevents the development of cutaneous and pulmonary fibrosis by blocking the activation of the Ras-ERK pathway in the oxidant-stress animal model of SSc.

Oxidative stress and thyroid impairment after gibberellic acid treatment in pregnant and lactating rats and their offspring

Gibberellic acid (GA₃) has been worldwide used in agriculture as a plant growth regulator. The purpose of this study is to assess the effects of GA₃ on the morphology and the thyroid hormone levels in adult rats and their suckling pups. Animals were given daily 200 ppm GA₃ in drinking water from the 14th day of pregnancy until day 14 after delivery. Compared with a control group, GA₃-treated mothers and pups showed an increase in body and thyroid weights, a decrease in plasma FT₄ and FT₃ levels, which were more pronounced in pups than in their mothers. Thyroid iodine content was also decreased in pups. These biochemical modifications corresponded histologically; the majority of follicles had cubical epithelial cells, which surrounded empty vesicular cavities. Toxicity was objectified by a significant increase in plasma malondialdehyde, protein carbonyls, and advanced oxidation protein products levels in GA₃-treated dams and their suckling pups; while, the activities of superoxide dismutase, catalase, and glutathione peroxidase were decreased in plasma of both dams and their pups. Moreover, a significant decline was observed in plasma glutathione, nonprotein thiols, and vitamin C levels. We conclude that GA₃ treatment affects thyroid function and plasma antioxidant status in adult rats and their progeny.

Oxidative stress induced by thyroid dysfunction in rat erythrocytes and heart

The aim of this study was to determine whether the effects of thyroid dysfunction induce oxidative stress in the blood and heart of male Wistar rats. Rats were randomly divided into three groups: group I served as control rats. Group II was treated daily with 0.05% benzythiouracile (BTU) administered in drinking water. Rats of group III have received l-thyroxine sodium salt (0.0012%), in drinking water. The results showed that thyroid dysfunction rats had poor growth performance. On the other hand, in hyperthyroid rats, a marked decrease compared with control occurred of some hematological parameters such red blood cell number (RBC), haemoglobin (Hb) concentration and haematocrit (Ht). There was also a significant increase in erythrocyte numbers and heart TBARS concentrations in hypothyroid rats compared with control. These results were associated with a fall in the total antioxidant status (TAS) in the serum of the hyperthyroid rats. Alteration of the antioxidant system in the hypo-/hyperthyroidism-induced rats was confirmed by the significant increase of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities and a decline in glutathione (GSH) content in both tissues were detected in hyperthyroid group compared to controls. On the other hand, serum transaminase activities (aspartate transaminase (AST); alanine transaminase (ALT)) were elevated indicating hepatic cellular damage after treatment with exogenous L-thyroxine. Moreover, serum lactate dehydrogenase (LDH), gamma-glutamyl transferase (GGT) and creatine phosphokinase (CPK) activities were increased in the hyperthyroidism rats. These results indicated that excessive thyroxin (long term) ingestion had an adverse effect on animal health and performance. We conclude that thyroid dysfunction induces oxidative stress and modifies some biochemical parameters of erythrocytes, heart and liver disease; our results show the occurrence of a state of oxidizing stress in relation to hyperthyroidism.

Effect of melatonin on burn-induced gastric mucosal injury in rats

We studied the effect of melatonin treatment on gastric mucosal damage induced by experimental burns and its possible relation to changes in gastric lipid peroxidation status. Melatonin was intraperitoneally applied immediately after third-degree burns over 30% of total body skin surface area of rats. Malondialdehyde (MDA), uric acid (UA) and sulphydril (SH) levels were determined in gastric mucosa and blood plasma and used as biomarkers of the oxidative stress. The results showed that the skin burn caused oxidative stress evidenced by accumulation of MDA and UA as well as the depletion of SHs in gastric mucosa. Plasma MDA concentrations were elevated, while plasma SH concentrations were decreased after burns. Melatonin (10 mg per kg body weight) protected gastric mucosa from oxidative damage by suppressing lipid peroxidation and activating the antioxidant defence. It may be hypothesised that melatonin restores the redox balance in the gastric mucosa and protects it from burn-induced oxidative injury. Melatonin has no significant influence on the concentrations of plasma MDA and antioxidants after burn; therefore, it should largely be considered as a limiting factor for tissue-damage.