Rat Thyroid Research Articles

Prolonged exposure to NaAsO2 induces thyroid dysfunction and inflammatory injury in Sprague‒Dawley rats, involvement of NLRP3 inflammasome‒mediated pyroptosis.

Arsenic, a well-known hazardous toxicant, has been found in recent years to act as an environmental endocrine disruptor that accumulates in various endocrine organs, impeding the normal physiological functions of these organs and altering hormone secretion levels. Moreover, some research has demonstrated a correlation between arsenic exposure and thyroid functions, suggesting that arsenic has a toxicological effect on the thyroid gland. However, the specific type of thyroid gland damage caused by arsenic exposure and its potential molecular mechanism remain poorly understood. In this study, the toxic effects of sodium arsenite (NaAsO2) exposure at different doses (0, 2.5, 5.0 and 10.0mg/kg bw) and over different durations (12, 24 and 36 weeks) on thyroid tissue and thyroid hormone levels in Sprague‒Dawley (SD) rats were investigated, and the specific mechanisms underlying the effects were also explored. Our results showed that NaAsO2 exposure can cause accumulation of this element in the thyroid tissue of rats. More importantly, chronic exposure to NaAsO2 significantly upregulated the expression of NLRP3 inflammasome-related proteins in thyroid tissue, leading to pyroptosis of thyroid cells and subsequent development of thyroid dysfunction, inflammatory injury, epithelial-mesenchymal transition (EMT), and even fibrotic changes in the thyroid glands of SD rats. These findings increase our understanding of the toxic effects of arsenic exposure on the thyroid gland and its functions.

Hazard assessment of fenozan, a released non-intentionally added substance from polyester-based can coating

Since the safety of new-generation polyester-based internal coatings regarding the migration of non-intentionally added substances (NIAS) is poorly documented, studies are needed to identify NIAS originating from these food-contact materials (FCM). The aim of this study was to identify volatile and semi-volatile NIAS from polyester-based coatings in order to assess their hazard and ensure consumers’ safety with regard to exposure from canned food. Extraction and migration tests were carried out on a single polyester-coated tin plate (5 batches) using two solvents: acetonitrile and ethanol 95%, then FCM’s extracts and migrates were analysed by GC-MS. An antioxidant degradation (hydrolysis) product, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid or fenozan (CAS RN: 20170-32-5), was identified and confirmed by reference standard in all migrates. To assess fenozan’s toxicity, several in vitro bioassays, such as the Ames test (to assess point mutation), the micronucleus assay (to detect chromosomal aberrations), and the iodide uptake assay (to study one mode of action for thyroid disruption) were conducted. Fenozan was negative in the Ames test on three strains of S. typhimurium (TA98, TA100, and TA1535) and on one strain of E.coli (WP2), with and without metabolic activation system (S9 mix) using direct incorporation and pre-incubation methods. The in vitro micronucleus assay conducted on HepG2 cells also exhibited a negative response following a 4-hour treatment with the S9 mix, and a 48-hour treatment without the S9 mix. A weak inhibitory effect was obtained when testing fenozan in the iodide uptake assay using rat thyroid FRTL-5 cells. Significant inhibition started from 800 µM of fenozan, with a maximal inhibition of almost 47% at 1000 µM. The findings indicate that fenozan exhibits an anti-thyroid activity in vitro.

In vitro study of the UV-filter homosalate effects on rat and human thyroid cells

Homosalate is a UV-B filter, commonly used in sunscreens and personal-care products. Homosalate was shown to exert estrogenic and anti-androgenic effects in animal models, while few data are available on the effects of Homosalate on thyroid cells. The aim of this study was to evaluate if Homosalate exposure could exert adverse effect on thyroid cells in vitro.FRTL-5 and NHT were treated with increasing concentration of Homosalate for 24-48-72 h. Cell viability was assessed by WST-1. Cell proliferation was evaluated by cristal violet. Micronucleus staining was performed to assess genotoxicity. mRNA levels of thyroid-related genes (TSHR, TPO, TG, NIS, and PAX8) were evaluated by RT-PCR. Changes in ROS production by FRTL-5 and NHT were assessed with H2DCFDA.Homosalate significantly reduced cell viability after 72 h in FRTL-5 starting from the concentration 250 μM, while in NHT, Homosalate exposure significantly reduced cell viability after 48 and 72 h only at highest concentration (2000 μM). Cell proliferation was not modified by Homosalate at any concentration and time-point. Homosalate significantly up-regulated mRNA expression levels of TPO and Tg genes in FRTL-5, while a significant increase only in Tg mRNA expression was observed in NHT. No changes in ROS production was found in both cell types.The present study suggest that the effects of Homosalate exposure may differ according to the type of cell tested. The in vitro exposure of thyroid cells to Homosalate produces: i) cytotoxicity at high concentrations or after long time of incubation, ii) genotoxicity only in rat thyroid cells at the highest concentration, iii) upregulation of Tg mRNA in both thyroid cell types and of TPO mRNA in rat thyroid cells, iv) no changes in cell proliferation or oxidative stress. Further studies on the effects of Homosalate on thyroid cells should be encouraged.

Haizao–Gancao herb pair ameliorates propylthiouracil-induced goiter by regulating the Beclin1-mediated autophagy

Ethnopharmacological relevanceHaizao, Sargassum, is widely used to treat goiter. Gancao, Glycyrrhizae radix et rhizome, is renowned for reducing toxicity or increasing effects in traditional Chinese medicine. As a classic herb pair, Haizao–Gancao (HG) is a commonly used and effective combined therapy for goiter. The underlying biological mechanisms of HG on goiter is still unclear. Aim of the studyTo explore the effect of HG on goiter, employing molecular docking combined with experimental validation to elucidate the molecular mechanism. Materials and methodsThe rat goiter model was created by gavageing propylthiouracil (PTU) intragastrically for a duration of 14 days. The rats had been separated into six groups: control, model, euthyrox, HG high-dose (HG-H), medium-dose (HG-M) and low-dose (HG-L) group. Based on general observations (such as the rats' living status, body weight, and rectal temperature), the relative weight of the thyroid, thyroid function, hematoxylin-eosin (HE) staining, and transmission electron microscopy (TEM) to view the pathological variations of the thyroid glands, the effect of HG was evaluated. Discovered the chemical composition of HG by UPLC-MS/MS and the possible targets were predicted adopting several databases. Next, we explored their pharmacological mechanisms using molecular docking and validated key targets using western blotting (WB) and co-immunoprecipitation (Co-IP). ResultsHG significantly increased the levels of triiodothyronine(T3), free triiodothyronine (FT3), free thyroxine (FT4), gained body weight and reduced tumescent thyroid glands in PTU-induced rats. The model group pathological changes such as uneven size, irregular shape and disordered arrangement of follicular epithelial cells occurred. However, HG groups thyroid follicles and epithelial cells appeared apparently normal. A variety of characteristic changes of autophagic vesicles appeared in the HG groups as opposed to the model group. In conclusion, the HG-L showed the best therapeutic effect. By UPLC-MS/MS, the major chemical components of HG were identified. The result revealed that HG contained flavonoids, alkaloids, organic acids, phenolic acidsand and terpenoids, etc. The molecular docking results of formononetin and naringenin and Beclin1 protein showed a high interaction of -5.38 kcal/mol and -5.25 kcal/mol. This implies that formononetin and naringenin may have a therapeutic effect in goiter rats by controlling the Beclin1-mediated autophagy. Western Blot (WB) and co-immunoprecipitation (Co-IP) results showed that HG can disrupt Beclin1/class III phosphatidylinositol 3-kinase(PI3KC3) binding and promote Beclin1/B-cell leukemia/lymphoma-2(Bcl-2) complex formation. Taken together, results demonstrate that autophagy inhibition via reducing Beclin1/PI3KC3 formation and increasing Beclin1/Bcl-2 binding activity. ConclusionsHG ameliorates propylthiouracil-induced goiter by regulating the Beclin1-mediated autophagy, thus promoting the autophagy of thyroid cells.

Distinct transcriptional profiles in rat thyroid glands after developmental exposure to three in vitro thyroperoxidase inhibiting chemicals

Thyroperoxidase (TPO) is central in thyroid hormone (TH) synthesis and inhibition can lead to TH deficiency. Many chemicals can inhibit TPO activity in vitro, but how this may manifest in the developing thyroid gland at the molecular level is unclear. Here, we characterized the thyroid gland transcriptome of male rats developmentally exposed to the in vitro TPO-inhibitors amitrole, 2-mercaptobenzimidazole (MBI), or cyanamide by use of Bulk-RNA-Barcoding (BRB) and sequencing. Amitrole exposure caused TH deficiency and 149 differentially expressed genes in the thyroid gland. The effects indicated an activated and growing thyroid gland. MBI caused intermittent changes to serum TH concentrations in a previous study and this was accompanied by 60 differentially expressed genes in the present study. More than half of these were also affected by amitrole, indicating that they could be early effect biomarkers of developmental TH system disruption due to TPO inhibition. Further work to validate the signature is needed, including assessment of substance independency and applicability domain.

The possible protective effect of ginger extract on toxic changes induced by bisphenol A on the thyroid gland of adult male albino rats: light and electron microscopic study.

Bisphenol A (BPA) is a chemical substance used in the plastic industry and considered as an endocrine disruptor. Ginger is a herbal material used in the food industry and has antioxidant activity. The present study was performed to evaluate the histological changes in the thyroid gland of adult male albino rats after intake of BPA and if there is any protective role for ginger extract (GE). Eighty adult male rats were divided equally into four groups. Group I as a control group, group II included rats that received 250 mg/kg/day GE orally for eight weeks, group III included rats that received 200 mg/kg/day BPA orally for the same period and group IV included rats that received BPA in the same dose for the same duration concomitantly with GE. At the end of the experiment, blood samples were taken for hormonal essay and tissue samples were processed. Light and electron microscopic studies were done. Morphometric and statistical studies were carried out. Group III showed degenerative changes in the thyroid gland, decreased serum levels of T3 and T4 and a strong positive inducible nitric oxide synthase (iNOS) immune response. Group IV showed restoration of thyroid gland architecture and function. In conclusion, GE protected the thyroid structure from the damaging effect of BPA oxidative stress through its anti-oxidant effect, thus preserving thyroid activity.

Medium-Chain Chlorinated Paraffins Trigger Thyroid Hormone Synthesis and Interfere with Mitochondrial Function in the Thyroid Gland.

Medium-chain chlorinated paraffins (MCCPs, C14-C17) are frequently detected in diverse environmental media. It has been proposed to be listed in Annex A of the Convention on Persistent Organic Pollutants in 2023. Although MCCPs are a crucial health concern, their toxicity remains unclear. This study investigated the toxic effects of MCCPs (0.1-50 mg/kg body weight/day) on the thyroid gland of female Sprague-Dawley rats and characterized the potential toxic pathways via transcriptomics and metabolomics approaches. MCCPs exposure caused histopathological changes to the endoplasmic reticula and mitochondria in thyroid follicular cells at a dose of 50 mg/kg bw/d and increased serum thyrotropin-releasing hormone, thyroid-stimulating hormones, and thyroxine when exposed to a higher dose of MCCPs. Transcriptomic analysis indicated the excessive expression of key genes related to thyroid hormone synthesis induced by MCCPs. Integrating the dual-omics analysis revealed mitochondrial dysfunction of the thyroid by mediating fatty acid oxidation, Kreb's cycle, and oxidative phosphorylation. Significant metabolic toxicity on the thyroid might be linked to the characteristics of the chlorine content of MCCPs. This study revealed the toxicity of MCCPs to the thyroid gland via triggering thyroid hormone synthesis and interfering with mitochondrial function, which can provide new insights into the modes of action and mechanism-based risk assessment of MCCPs.

Thyroid-disrupting effects of bisphenol S in male Wistar albino rats: Histopathological lesions, follicle cell proliferation and apoptosis, and biochemical changes.

In this presented study, the aim was to investigate the toxic effects of bisphenol S (BPS), one of the bisphenol A analogues, on the thyroid glands of male Wistar albino rats. Toward this aim, the rats (n = 28) were given a vehicle (control) or BPS at 3 different doses, comprising 20, 100, and 500mg/kg of body weight (bw) via oral gavage for 28days. According to the results, BPS led to numerous histopathological changes in the thyroid tissue. The average proliferation index values among the thyroid follicular cells (TFCs) displayed increases in all of the BPS groups, and significant differences were observed in the BPS-20 and BPS-100 groups. The average apoptotic index values in the TFCs were increased significantly in the BPS-500 group. The serum thyroid-stimulating hormone and serum free thyroxine levels did not show significant changes after exposure to BPS; however, the serum free triiodothyronine levels displayed significant decreases in all 3 of the BPS groups. BPS was determined to cause significant increases in the antioxidant enzyme activities of catalase, superoxide dismutase, glutathione-S-transferase, glutathione peroxidase, as well as a significantly decreased content of reduced glutathione. The malondialdehyde level in the thyroid tissue was elevated significantly in the BPS-500 group. The data obtained herein revealed that BPS has thyroid-disrupting potential based on structural changes, follicle cell responses, and biochemical alterations including a decreased serum free triiodothyronine level and increased oxidative stress.

Combined transcriptome and microbiome analysis reveals the thyrotoxic effects of PM2.5 in female rats

Pervasive environmental pollutants, specifically particulate matter (PM2.5), possess the potential to disrupt homeostasis of female thyroid hormone (TH). However, the precise mechanism underlying this effect remains unclear. In this study, we established a model of PM2.5-induced thyroid damage in female rats through intratracheal instillation and employed histopathological and molecular biological methods to observe the toxic effects of PM2.5 on the thyroid gland. Transcriptome gene analysis and 16S rRNA sequencing were utilized to investigate the impact of PM2.5 exposure on the female rat thyroid gland. Furthermore, based on the PM2.5-induced toxic model in female rats, we evaluated its effects on intestinal microbiota, TH levels, and indicators of thyroid function. The findings revealed that PM2.5 exposure induced histopathological damage to thyroid tissue by disrupting thyroid hormone levels (total T3 [TT3], (P < 0.05); total T4 [TT4], (P < 0.05); and thyrotropin hormone [TSH], (P < 0.05)) and functional indices (urine iodine [UI], P > 0.05), thus further inducing histopathological injuries. Transcriptome analysis identified differentially expressed genes (DEGs), primarily concentrated in interleukin 17 (IL-17), forkhead box O (FOXO), and other signaling pathways. Furthermore, exposure to PM2.5 altered the composition and abundance of intestinal microbes. Transcriptome and microbiome analyses demonstrated a correlation between the DEGs within these pathways and the flora present in the intestines. Moreover, 16 S rRNA gene sequencing analysis or DEGs combined with thyroid function analysis revealed that exposure to PM2.5 significantly induced thyroid hormone imbalance. We further identified key DEGs involved in thyroid function-relevant pathways, which were validated using molecular biology methods for clinical applications. In conclusion, the homeostasis of the "gut-thyroid" axis may serve as the underlying mechanism for PM2.5-induced thyrotoxicity in female rats.

Impact of Peganum harmala/Zinc Oxide Nanoparticles on Thyroid and Pancreatic Function in Obese Rats: A Biochemical and Physiological Analysis

Impact of Peganum harmala/Zinc Oxide Nanoparticles on Thyroid and Pancreatic Function in Obese Rats: A Biochemical and Physiological Analysis

Control of ENaC ubiquitination.

Ubiquitination influences the expression of the epithelial Na+ channel (ENaC). We assessed the mechanisms of selective ubiquitination of the mature, cleaved form of γENaC in both native rodent kidneys and Fisher rat thyroid (FRT) cells expressing the channel heterologously. In both models, singly cleaved and fully cleaved γENaCs were strongly ubiquitinated, implying that the second cleavage releasing an inhibitory peptide was not essential for the process. To see whether location of the protein in or near the apical membrane rather than cleavage per se influences ubiquitination, we studied mutants of γENaC in which cleavage sites are abolished. These subunits were ubiquitinated only when coexpressed with α- and βENaC, facilitating trafficking through the Golgi apparatus. To test whether reaching the apical surface is necessary we performed in situ surface biotinylation and measured ENaC ubiquitination in the apical membrane of rat kidney. Ubiquitination of cleaved γENaC was similar in whole kidney and surface fractions, implying that both apical and subapical channels could be modified. In FRT cells, inhibiting clathrin-mediated endocytosis with Dyngo-4a increased both total and ubiquitinated γENaC at the cell surface. Finally, we tested the idea that increased intracellular Na+ could stimulate ubiquitination. Administration of amiloride to block Na+ entry through the channels did not affect ubiquitination of γENaC in either FRT cells or the rat kidney. However, presumed large increases in cellular Na+ produced by monensin in FRT cells or acute Na+ repletion in rats increased ubiquitination and decreased overall ENaC expression.NEW & NOTEWORTHY We have explored the mechanisms underlying the ubiquitination of the γ subunit of epithelial Na+ channel (ENaC), a process believed to control channel internalization and degradation. We previously reported that the mature, cleaved form of the subunit is selectively ubiquitinated. Here we show that this specificity arises not from the cleavage state of the protein but from its location in the cell. We also show that under some conditions, increased intracellular Na+ can stimulate ENaC ubiquitination.

Effect of Amiodarone on the Thyroid Gland of Adult Male Albino Rats: A Histological and Morphometric Study

Abstract Background Amiodarone (AMD) is a benzofuran derivative, used in management of angina and refractory ventricular arrhythmia. Amiodarone has been associated with toxicity on many organs involving the lungs, thyroid gland, liver, eyes, skin, and nerves. Aim of the Work The aim of the current work was to study the structural and functional changes of the thyroid gland of adult male albino rats after exposure to the antiarrhythmic drug “Amiodarone”. Material and Methods Thirty adult male albino rats were used and divided into three groups. The first group included 10 rats which served as (control); 5 rats received distilled water orally and 5 rats received 3 ml of 0.6% methylcellulose. The second group included 10 rats used as (therapeutic dose treated group), which received 30 mg/Kg B.W. of amiodarone for 12 weeks by oral gavage, while the third group included 10 rats used as a (toxic dose treated group) which received 60 mg/Kg b. w. of amiodarone daily for 6 weeks by oral gavage. Serum concentration of tri-iodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH) were evaluated. Morphometric study and statistical analysis were done. Results Biochemical examination revealed statistical highly significant increase (P &amp;lt; 0.001) of serum (T4 &amp; T3) with concomitant statistical highly significant decrease of (TSH) (P &amp;lt; 0.001). Histopathological examination of the thyroid tissues from the therapeutic dose treated group showed marked evidence of thyrotoxicosis in the form of microcystic follicular changes and peripheral scalloping, cellular degeneration with scanty cytoplasm and vesicular nuclei. These changes became more severe in toxic dose treated group in the form of thyroid tissue damage with hemorrhage and necrosis. Epithelial hyperplasia with atypical nuclear features were also detected. Conclusion Amiodarone had detrimental effects on the adult male albino rat’s thyroid tissue when administered either in the therapeutic or the toxic doses.

Titanium dioxide nanoparticles Disrupt ultrastructure and function of Rat thyroid tissue via oxidative stress

Nano-TiO2 is widely used in various fields such as industry, daily necessities, food and medicine. Previous studies have shown that it can enter mammalian tissues through the digestive tract or respiratory tract and have effects on various organs and systems. However, the effect of nano-TiO2 on the mammalian thyroid gland has not been reported. In this study, we fed SD rats with rutile nano-TiO2 at a dose of 5 mg/kg body weight for 3 weeks, and then examined the thyroid histology and thyroid function of the rats. In vitro experiments were conducted to determine the effects of nano-TiO2 on the viability, apoptosis, inflammatory factors, antioxidant enzymes, and oxidative stress of human thyroid follicular epithelial cells. Histological evidence showed abnormal morphology of rat thyroid follicles and organelle damage in follicular epithelial cells. Nano-TiO2 caused a decrease in the level of sodium/iodide symporter (NIS), an increase in the level of apoptotic protein cleaved-caspase 3, and an increase in the levels of pro-inflammatory factors IL-1β and TNF-α in rat thyroid tissue. Nano-TiO2 also resulted in increased serum FT4 and TPO-Ab levels. In in vitro experiments, nano-TiO2 reduced the viability of human thyroid follicular cells, downregulated the levels and activities of antioxidant enzymes CAT, GPX1 and SOD, and increased the levels of ROS and MDA caused by oxidative stress. These results indicate that nano-TiO2 damages the structure and function of thyroid follicular epithelial cells through oxidative stress. Long-term exposure to nano-TiO2 could be a potential risk factor for thyroid dysfunction.

Effect of progestin on thyroid function in female Wistar rats.

To characterize the influence of female-specific hormones on women's thyroid function, the study investigated the influence of extra progestin from oral contraceptives on inducing thyroid dysfunction. Sixty female Wistar rats were divided into six groups based on levonorgestrel or desogestrel administration as the main active agents: control, low (0.0039 mg*20-fold), medium (0.0039 mg*100-fold), high (0.0318 mg*100-fold) levonorgestrel (pure product); and low (0.0083 mg*20-fold) and high (0.0083 mg*100-fold) desogestrel (pure product). Progestin was administered by gavage every 4 days for 1 month. Statistical analysis was performed using one-way analysis of variance and the Kruskal-Wallis test. Following levonorgestrel gavage, serum free T4 and thyroidstimulating hormone levels were significantly lower in the experimental group than that in the control group (p=0.013 and 0.043). After desogestrel gavage, the serum free T4 and free T3 levels were lower in the experimental group than that in the control group (p=0.019 and 0.030). Thyroid hormone antibody concentrations were lower in rats administered levonorgestrel and desogestrel than that in control rats. Moreover, exposure to progestin upregulated the expression of the thyroid-stimulating hormone receptor and sodium iodide symporter in thyroid. Progestin stimulation enhanced the proliferation of follicular epithelial cells in rat thyroid tissues. Progestin exposure could cause thyroid dysfunction by upregulating the transcription of thyroid-stimulating hormone receptor and sodium iodide symporter in thyroid, thus inducing pathomorphological changes in rats' thyroid.

Evaluation of Toxic Effects of Caffeinated Energy Drinks on Thyroid Gland of Adult Male Albino Rats: Assessment of Apoptosis and Regeneration

Evaluation of Toxic Effects of Caffeinated Energy Drinks on Thyroid Gland of Adult Male Albino Rats: Assessment of Apoptosis and Regeneration

Vitamin C Ameliorated Perfluorooctanoic Acid -Induced Thyroid and Testicular Dysfunction in Adult Male Rats

Vitamin C Ameliorated Perfluorooctanoic Acid -Induced Thyroid and Testicular Dysfunction in Adult Male Rats

In vitro assessment of thyroid peroxidase inhibition by chemical exposure: comparison of cell models and detection methods

Disruption of the thyroid hormone (TH) system is connected with diverse adverse health outcomes in wildlife and humans. It is crucial to develop and validate suitable in vitro assays capable of measuring the disruption of the thyroid hormone (TH) system. These assays are also essential to comply with the 3R principles, aiming to replace the ex vivo tests often utilised in the chemical assessment. We compared the two commonly used assays applicable for high throughput screening [Luminol and Amplex UltraRed (AUR)] for the assessment of inhibition of thyroid peroxidase (TPO, a crucial enzyme in TH synthesis) using several cell lines and 21 compounds from different use categories. As the investigated cell lines derived from human and rat thyroid showed low or undetectable TPO expression, we developed a series of novel cell lines overexpressing human TPO protein. The HEK-TPOA7 model was prioritised for further research based on the high and stable TPO gene and protein expression. Notably, the Luminol assay detected significant peroxidase activity and signal inhibition even in Nthy-ori 3-1 and HEK293T cell lines without TPO expression, revealing its lack of specificity. Conversely, the AUR assay was specific to TPO activity. Nevertheless, despite the different specificity, both assays identified similar peroxidation inhibitors. Over half of the tested chemicals with diverse structures and from different use groups caused TPO inhibition, including some widespread environmental contaminants suggesting a potential impact of environmental chemicals on TH synthesis. Furthermore, in silico SeqAPASS analysis confirmed the high similarity of human TPO across mammals and other vertebrate classes, suggesting the applicability of HEK-TPOA7 model findings to other vertebrates.

Long-term gene expression changes in the rat thyroid by neonatal irradiation - a possible mechanism related to thyroid carcinogenesis by childhood radiation

Long-term gene expression changes in the rat thyroid by neonatal irradiation - a possible mechanism related to thyroid carcinogenesis by childhood radiation

Retromer- and Retriever-Associated Sorting Nexins Regulate Traffcking of KCa2.3 Channels

Correct function of the Ca2+-activated K+ channel KCa2.3 (SK3) is essential for several physiological processes. Activity of KCa2.3 in neurons modulates the rate of action potential firing; in endothelial cells activation of KCa2.3 channels induces vasodilation, and accordingly, a decrease in blood pressure. KCa2.3 activity (i.e. currents) can be modulated by two main variables: the open probability ( Po) and the number of channels inserted into the plasma membrane ( N). Numerous pharmacological compounds have been identified and developed to alter KCa2.3 Po. In contrast, the mechanisms that control delivery of KCa2.3 to and from the plasma membrane are still poorly understood. After endocytosis, plasma membrane proteins are targeted to the endosomal network which is a key area for sorting membrane-bound proteins. Several endosomal-associated coat complexes have been identified that ‘rescue’ proteins from degradation and sequester proteins into recycling tubules for transport back to the plasma membrane. These complexes include Retromer, Retriever, and Commander. Associated with these complexes are members of the Sorting Nexin (SNX) family. SNX proteins bind to specific amino acid motifs to sort proteins for Retromer- or Retriever-mediated recycling. Interestingly, the Devor laboratory has demonstrated KCa2.3 can be rapidly recycled back into the plasma membrane after endocytosis. Based on those data, we hypothesised that the Retromer and Retriever complexes regulate KCa2.3 recycling. To investigate this, we are using biochemical [e.g. cell surface biotinylation, co-immunoprecipitation (co-IP)] and electrophysiological (e.g. patch-clamp) techniques. First, we determined the role of SNXs in KCa2.3 traffcking by using siRNA to knock down SNX protein expression in Fisher rat thyroid (FRT) cells expressing heterologous KCa2.3. Knockdown of Retromer-associated SNX3 or Retriever-associated SNX17 significantly decreased the cell surface population of KCa2.3 ( P&lt;0.01, n=4, each). With protein-protein interaction experiments, KCa2.3 co-IPed with SNX17 and SNX3, but not Retromer-associated SNX27 ( n=3, each). Electrophysiology experiments are underway to determine if the knockdown of SNXs alters the functional expression of KCa2.3. and We are also investigating if KCa2.3 traffcking in primary endothelial cells requires SNX3 and SNX17. These results suggest that SNX3 and SNX17 are novel regulators of KCa2.3 traffcking. This work was supported by grants from NIH (HL083060, HL092157) and the Cystic Fibrosis Foundation (DEVOR20GO) to D.C.D.; Lottery Health New Zealand (R-LHR-2019-101706) to F.J.M.; and Aim Fund grant to K.L.H., and the Department of Physiology, University of Otago. M.J.E.L. was supported by a doctoral scholarship from the University of Otago. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effect of Electromagnetic Radiation of Wi-Fi Router on Thyroid Gland and the Possible Protective Role of Combined Vitamin C and Zinc Administration in Adult Male Albino Rats.

Electromagnetic radiation (EMR) is widely used nowadays in various fields due to rapid expansion of technology and affects different organs such as endocrine glands. Antioxidants protect the cells and act as a free radical scavenger. The aim of the study was to clarify the effect of EMR emitted from Wi-Fi router on the thyroid gland of adult male albino rats and the possible protective role of combined Vitamin C and zinc. Thirty adult male albino rats were divided into three groups: Group I (control group), Group II (received combined Vitamin C and Zinc in one tablet called IMMUNO-MASH), and Group III (experimental groups). Group III was divided into two subgroups (A and B) according to the duration of exposure: 6 h and 24 h/day. Each of these groups was divided into two equal subgroups. One was exposed only to EMR while the other was exposed to EMR and received combined Vitamin C and zinc. All rats were weighed at the beginning and at the end of the experiment. The thyroid gland was prepared for general histological, anti-calcitonin immunostaining, and ultrastructural study. Furthermore, measurement of total serum T3, T4, and thyroid-stimulating hormone (TSH) hormone levels and quantitative analysis of immunoreactive C-cells were done. Then, statistical analysis was done on the number of immunoreactive C-cells, data of the body weight, and the hormonal levels. A highly significant increase in the body weight in subgroups exposed to EMR for 24 h/day was observed. Furthermore, they showed a highly significant decline in T3 and T4 levels together with a highly significant increase in TSH level. With increasing period of exposure, there was a variable degree of deterioration in the form of congestion and dilatation of blood vessels, cellular infiltration, follicular disintegration, vacuolar degeneration, and desquamated follicular cells in the colloid. The C-cells showed a significant increase in the mean number compared with the control group. Ultrastructural analysis of follicular cells revealed colloid droplets, deteriorations in rough endoplasmic reticulum, degenerating nuclei, and swollen mitochondria according to the dose of exposure. There was apparent improvement with the use of combined Vitamin C and zinc. Wi-Fi radiation has a very serious effect on thyroid gland morphology and activity. Moreover, experimentally induced hypothyroidism by radiation resulted in increased C-cell number. Combined Vitamin C and zinc could have a protective role against this tissue damage.