Histological and ultrastructural alterations of rat thyroid gland after short-term treatment with high doses of thyroid hormones

Nigella sativa oil restores hormonal levels, and endocrine signals among thyroid, ovarian, and uterine tissues of female Wistar rats following sodium fluoride toxicity

The current study aimed to explore the possible prophylactic and therapeutic effect of Nigella sativa L. oil (NSO) against disruption of endocrine signals and injuries in the thyroid gland, ovary, and uterine tissues induced by sodium fluoride (NaF). Twenty-eight mature female Wistar rats were randomly allocated into four experimental groups (n = 7/group) as follows: control group; NaF group, orally received NaF (20 mg/kg b.wt.) daily; NSO/NaF, orally received NSO (300 mg/kg b.wt.) two weeks before being given NaF and continued throughout the experiment; and NSO+NaF group orally received NSO concurrently with NaF. Our results indicated that NSO restored hormonal balance and suppressed oxidative damage and inflammation. Moreover, the levels of triiodothyronine, thyroxine, thyroid peroxidase, estrogen (E2), progesterone, follicle-stimulating hormone, and luteinizing hormone were elevated, while prostaglandins F2-α and cortisol levels were decreased in NSO treated groups compared to NaF-intoxicated rats. As well, NSO significantly boosted levels of antioxidant molecules, and lowered lipid peroxidation of examined tissues, unlike NaF-treated group. NSO also up-regulated antioxidant enzymes, anti-apoptotic protein, zona pellucida sperm-binding protein, bone morphogenetic protein, and thyroid stimulating hormone, conversely down-regulated inflammatory cytokines, apoptotic proteins, estrogen receptor-α, estrogen receptor-β, and thyroid stimulating hormone receptors compared to NaF-intoxicated group. Additionally, NSO ameliorated tissue damage of the thyroid gland, ovary, and uterus induced by NaF. -Overall, the prophylactic group (NSO/NaF) performed better antioxidant and anti-inflammatory activities than the treated group almost in all examined tissues, which is reflected by the improvement in the structure of the thyroid, ovarian, and uterine tissues.

Effects of perchlorate and exogenous T4 on growth, development and tail resorption of Rana chensinensis

Endocrine disruptors have been demonstrated to exert adverse effects on growth and development of amphibians by disrupting hormone levels. Tail resorption, which is one of the most remarkable events during amphibian metamorphosis, is closely associated with thyroid hormones levels. However, limited research has been conducted on the effects of endocrine disruptors on tail resorption in amphibians. This study explored the effects of NaClO4 and T4 on the growth, development and tail resorption during the metamorphosis of Rana Chensinensis. The results demonstrated that exposure to NaClO4 led to an increase in body size and a delay in metamorphosis of R. Chensinensis tadpoles. Histological analysis revealed that both NaClO4 and exogenous T4 exposure resulted in thyroid gland injury, and NaClO4 treatment delayed the degradation of notochord and muscles, thereby delaying tail resorption. Moreover, transcriptome sequencing results showed that apoptosis-related genes (APAF1, BAX and CASP6) and cell component degradation-related genes (MMP9 and MMP13) were highly expressed in the T4 exposure group, and the expression of oxidative stress-related genes (SOD and CAT) was higher in the NaClO4 exposure group. Taken together, both NaClO4 and exogenous T4 affect tail resorption in R. Chensinensis, thereby affecting their adaptation to terrestrial life. The present study will not only provide a reference for future experimental research on the effects of other endocrine disruptors on the growth, development and tail resorption of amphibians but will also provide insights into environmental protection and ecological risk assessment.

The possible protective role of vitamin C versus melatonin on potassium dichromate induced changes in rat thyroid gland: light and electron microscopic study

Potassium dichromate is widely used in various laboratory and industrial applications. Vitamin C and melatonin are well-known antioxidants. Study the microscopic and morphometric alterations in the thyroid gland in adult male albino rats after the administration of potassium dichromate for successive 2 months and also to assess the possible protective effect of vitamin C versus melatonin on these changes. Sixty adult male albino rats were randomly divided into four main groups. Group I (The control group). Group II received potassium dichromate (25 mg/kg/day) dissolved in distilled water by intraperitoneal (i.p) injection for 2 months. Group III received the same dose of potassium dichromate with vitamin C (120 mg/kg/day) orally through an intragastric intubation. Group IV received the same dose of potassium dichromate and melatonin (10 mg/kg/day) as an i.p injection. Thyroid gland samples were prepared for light and electron microscopic studies. Potassium dichromate group demonstrated congested blood vessels, follicular hyperplasia, follicular enlargement with degenerated lining cells that were exfoliated in the lumen. The parafollicular cells appeared with darkly stained nuclei. PAS reaction showed weak reaction in the colloid with an abnormal pattern of vacuolization. A highly significant increase in the percentage area of fibrosis was detected in Mallory trichrome sections. Ultrastructurally, follicular cells and parafollicular cells appeared irregular in shape with dark, small heterochromatic nuclei. Small, electron-dense granules in the parafollicular cells were found. Potassium dichromate and vitamin C-treated group III showed partial improvement of the thyroid gland. The PAS reaction showed that nearly all the follicles were more or less similar to those of the control group. A significant decrease in the percentage area of fibrosis in group III was found as compared to those in group II. Potassium dichromate and melatonin-treated group showed that the thyroid gland was nearly similar to that of the control group. Vitamin C and melatonin could partially protect against potassium dichromate induced changes in the thyroid gland and the protective effect of melatonin was better than that of vitamin C.

Iodine Status in Pregnant Women Having Urinary Fluoride in Contaminated Areas: A Case Study of Phayao Province

Fluoride naturally occurs in the Earth's crust and is widely dispersed in groundwater. The high consumption of fluoride can inhibit iodine metabolism in the human body, especially in the thyroid gland. This study assessed iodine knowledge, iodine consumption behavior, urinary iodine (UI), thyroid stimulating hormone (serum TSH), and free triiodothyronine3 (serum FT3) and examined the connection between fluoride exposure and UI and thyroid function as serum concentrations of TSH and FT3 in pregnant women dwelling in an area of endemic fluorosis. This was a cross-sectional study. The population included 152 pregnant women within the 1^st trimester of pregnancy, during which they were provided antenatal care (ANC) in seven public community hospitals in Phayao province, Thailand. The study consisted of two components. First, the study consisted of a questionnaire in which we evaluated the iodine knowledge and iodine consumptive behaviors in subjects. Second, biochemical data were investigated to evaluate thyroid function in the subjects. The gestational age of most subjects was 8-12 weeks. The study population has lived in fluoride-contaminated areas since birth (76.97%). The iodine and iodine consumption levels were moderate (50.00%). Their food iodine consumption was 3-4 days/week, and the top five consumption ranks were iodized salt, cooked pork, eggs, sticky rice, and iodine fish sauce. In terms of biochemical parameters, 63.16% of respondents had UI levels below 150.00 g/L, which is below the normal reference range of 150.00-249.00 g/L. 89.47% of the risk of hypothyroidism was associated with serum TSH levels below 2.50 g/L. In 38.16% of the samples, normal levels of serum FT3 (2.00-4.40 pg/L) were identified in the subjects. In addition, 61.84% of the samples had FT3 concentrations greater than 4.40 pg/L (high intake of iodine). The approved association between positive serum FT3 data and serum TSH was positive (r = 260 and p < 0.05). These studies imply that these elevated levels of TSH and FT3 place pregnant women in their first trimester at risk for hypothyroidism.

Broccoli Sprouts and Their Influence on Thyroid Function in Different In Vitro and In Vivo Models

Broccoli sprouts are a super vegetable; however, they have possible negative effects on thyroid function, which is especially important for patients with hypothyroidism. As the data on this issue are scarce, this study aimed to determine the safety and possible beneficial effect of broccoli sprouts both in vitro and in vivo. The in vitro model comprised the evaluation of the impact of broccoli sprouts on normal and neoplastic thyroid cells and the determination of their anti-inflammatory and antioxidant (IL-6, TNF-alpha, NO, and SOD) potential in macrophages. The in vivo model concerned the histopathological analysis of thyroid glands in healthy rats and rats with hypothyroidism (induced by iodine deficiency or sulfadimethoxine ingestion) fed with broccoli sprouts. The results of our study indicated that broccoli sprouts decreased the viability of thyroid cancer cells and prevented inflammation. The results also confirmed the satisfactory safety profile of the sprouts, both in vitro and in vivo; however, a further in-depth evaluation of this problem is still needed. Information on the influence of brassica vegetables on thyroid function is of great importance in terms of public health, particularly when taking into account that the risk of iodine deficiency, hypothyroidism, and thyroid cancer in the global population is still increasing.

The Impact of Kohlrabi Sprouts on Various Thyroid Parameters in Iodine Deficiency- and Sulfadimethoxine-Induced Hypothyroid Rats

Brassica sprouts, as the rich source of dietary glucosinolates, may have a negative effect on thyroid function. In this study, kohlrabi sprouts diet, combined with two models of rat hypothyroidism, was tested. TSH, thyroid hormones and histopathology analysis were completed with the evaluation of immunological, biochemical, haematological parameters, cytosolic glutathione peroxidase, thioredoxin reductase in the thyroid, and plasma glutathione peroxidase. A thermographic analysis was also adapted to confirm thyroid dysfunction. The levels of TSH, fT3 and fT4, antioxidant enzyme (GPX) as well as histopathology parameters remained unchanged following kohlrabi sprouts ingestion, only TR activity significantly increased in response to the sprouts. In hypothyroid animals, sprouts diet did not prevent thyroid damage. In comparison with the rats with iodine deficiency, kohlrabi sprouts diet decreased TNF-α level. Neither addition of the sprouts to the diet, nor sulfadimethoxine and iodine deficiency, caused negative changes in red blood cell parameters, glucose and uric acid concentrations, or kidney function. However, such a dietary intervention resulted in reduced WBC levels, and adversely interfered with liver function in rats, most likely due to a higher dietary intake of glucosinolates. Moreover, the possible impact of the breed of the rats on the evaluated parameters was indicated.

Effects of perchlorate and exogenous T4 exposures on development, metamorphosis and endochondral ossification in Bufo gargarizans larvae

Several endocrine-disrupting chemicals (EDCs) have been proven to interfere with the physiological function of thyroid hormone (TH), which affected growth and development. However, few studies have investigated the effects of EDCs on TH axis with consequence for skeletal development in amphibians. This study thus examined the potential role of perchlorate and T4 in growth, development and endochondral ossification during metamorphosis of Bufo gargarizans. Our studies showed that NaClO₄ treatment caused weight gain and delayed the developmental stage in B. gargarizans tadpoles, while T4 decreased body size and survival rate, accelerated metamorphic duration and increased the risk of early death. Histological sections suggested that NaClO₄ and T4 treatments caused damages to thyroid tissue, such as decreased thyroid gland size, follicle size, colloid area, the height of follicular epithelial cells and the number of follicles. In addition, the double skeletal staining and RT-qPCR showed that NaClO₄ and T4 treatments inhibited the endochondral ossification by regulating TH synthesis (TRs, Dios) and endochondral ossification-related genes (MMPs, Runxs, VEGFs and VEGFRs) expression levels, which might affect terrestrial locomotion and terrestrial life. Altogether, these thyroid injury and gene expression changes as caused by NaClO₄ and T4 may have an influence on development and endochondral ossification during the metamorphosis of amphibians.

The possible role of the seaweed Ulva fasciata on ameliorating hyperthyroidism-associated heart inflammations in a rat model

Cardiovascular diseases are key complications primarily associated with hyperthyroidism disorders. The present study sought to ameliorate hyperthyroidism-mediated cardiovascular inflammations and related oxidative stress paradigms in experimental rats using the broadly distributed green seaweed Ulva fasciata. Forty-eight adult male albino rats were recruited and randomly classified into six groups. Hyperthyroidism was stimulated using L-thyroxine sodium at a dose of 100 μg/kg i.p. for 3 weeks daily. Further, 200 mg/kg b.wt. concentration of the U. fasciata methanolic (U. fasciata-MeOH) extract was the recommended dose and administrated orally to the hyperthyroid rats. The standard commercial drug "propranolol hydrochloride" was also tested at a dose of 10 mg/kg i.p. to compare the findings obtained from the seaweed extract. A combined treatment with the U. fasciata-MeOH extract and propranolol hydrochloride was also assessed. Our results implied that the treatment of hyperthyroid rats with the U. fasciata-MeOH extract significantly reduced serum levels of the thyroid hormones T3 and T4, proinflammatory cytokines (TNF-α, MPO, and CRP), triglycerides and total cholesterol, as well as the cardiac biomarkers CK-MB, LDH, and troponin to thresholds close to those of the standard drug. In addition, levels of high-density lipoprotein cholesterol (HDL-C) and interleukin 10 (IL-10) were significantly upregulated. Hyperthyroid rats only treated with propranolol hydrochloride, or with a combination of the drug and the seaweed extract, conferred the same observations. Histopathological architecture boosted our interesting findings where the myocardium tissues in hyperthyroid rats, administrated the U. fasciata-MeOH extract or/and propranolol hydrochloride, exhibited more or less a normal structure as the control, reflecting the potential cardiovascular recovery exerted by this seaweed extract. In vitro DPPH, ABTS, and FRAP antioxidant assays of the U. fasciata-MeOH extract showed an outstanding ROS-scavenging potential. HPLC analysis of the U. fasciata-MeOH extract unraveled an inestimable valuable array of phenolics (mainly p-coumaric, gallic, ferulic, chlorogenic, and syringic acids) and flavonoids (hesperidin, kaempferol, catechin, quercetin, and rutin). Conclusively, the seaweed U. fasciata is a profitable source of antioxidant polyphenolics characterized by having a pharmaceutical potential against hyperthyroidism-linked cardiovascular inflammations and oxidative stress patterns due to their substantial free radical quenching properties, and also via regulating the signalling pathways of the proinflammatory, lipid profile, and cardiac biomarkers.

Diabetic Nephropathy: Novel Molecular Mechanisms and Therapeutic Targets

Diabetic nephropathy (DN) is one of the major microvascular complications of diabetes mellitus and the leading cause of end-stage kidney disease. The standard treatments for diabetic patients are glucose and blood pressure control, lipid lowering, and renin-angiotensin system blockade; however, these therapeutic approaches can provide only partial renoprotection if started late in the course of the disease. One major limitation in developing efficient therapies for DN is the complex pathobiology of the diabetic kidney, which undergoes a set of profound structural, metabolic and functional changes. Despite these difficulties, experimental models of diabetes have revealed promising therapeutic targets by identifying pathways that modulate key functions of podocytes and glomerular endothelial cells. In this review we will describe recent advances in the field, analyze key molecular pathways that contribute to the pathogenesis of the disease, and discuss how they could be modulated to prevent or reverse DN.

Effect of fluoride on endocrine tissues and their secretory functions -- review

The effects of fluoride on endocrine tissues has not been sufficiently explored to date. The current body of knowledge suggest significant effects of that mineral on reducing sex hormone levels, which may consequently impair fertility and disrupt puberty. The majority of studies confirm that sodium fluoride increases TSH levels and decreases the concentrations of T3 and T4 produced by the thyroid. Moreover, a correlation was observed between NaF and increased secretion of PTH by the parathyroid glands, without a significant impact on body calcium levels. Probably, fluoride may exert adverse effects on insulin levels, impairing pancreatic function and resulting in abnormal glucose tolerance. Observations also include decreased levels of cortisol secreted by the adrenal glands. In light of the few existing studies, the mechanism of fluoride toxicity on the endocrine system has been described.

Thyroid Hormone Signalling Alteration in Diabetic Nephropathy and Cardiomyopathy: a "Switch" to the Foetal Gene Programme

PURPOSE OF THE REVIEW

In this study, we will analyse how diabetes induces the reactivation of organs' developmental programmes and growth, discuss how thyroid hormone (TH) signalling orchestrates these processes, and suggest novel strategies for exploiting TH-mediated reparative and regenerative properties.

RECENT FINDINGS

Diabetes is a global pandemic that poses an enormous threat to human health. The kidney and the heart are among the organs that are the most severely damaged by diabetes over time. They undergo profound metabolic, structural, and functional changes that may be due (at least partially) to a recapitulation of their early developmental programmes. There is growing evidence to suggest that this foetal reprogramming is controlled by the TH/TH receptor alpha 1 (TRα1) axis. We introduce the hypothesis that in diabetes-and probably in other diseases-TH signalling acts in an antagonistic manner: it recapitulates a foetal profile that is necessary to coordinate metabolic and structural adaptations to sustain energy preservation and growth, but in the long term the persistent changes in these pathways are detrimental.

Histopathological and biochemical alterations of the parotid gland induced by experimental hypothyroidism in adult male rats and the possible therapeutic effect of Nigella sativa oil

Thyroid hormones are essential for metabolic rate regulation and play a role on the integrity of the salivary glands. Nigella sativa is a widely used plant in medicine. This study aimed to evaluate the effect of Nigella sativa oil (NSO) on the hypothyroidism-induced parotid gland pathological alterations. Rats were divided into four groups: control group, hypothyroid group: received daily oral carbimazole for 3 weeks, hypothyroid-NSO group: NSO was orally given for 4 weeks after hypothyroidism induction and NSO group: administrated NSO only for 4 weeks. After 7 weeks, all rats were sacrificed, serum thyroid hormones were estimated, and parotid glands were assessed by histopathological, immunohistochemical, ultrastructural and morphometric analyses. Hypothyroid group showed a significant decrease in thyroid hormones with increase in thyroid-stimulating hormone (TSH) levels and decrease in body and parotid weights compared to the control rats that were improved with NSO treatment. Sections of the hypothyroid group showed fibrosis, acinar cytoplasmic vacuolations, vascular congestion, ductal dilatation, wide intercellular canaliculi, nuclear pyknosis and decreased number of secretory granules. Also, there were decreased B-cell lymphoma 2 (Bcl-2) and increased p53, Bcl-2 Associated X (Bax) and alpha-smooth muscle actin (α-SMA) immune-expressions; with decreased Bax/ Bcl-2 ratio that all were attenuated by NSO. NSO ameliorates hypothyroidism-induced parotid changes by altering p53, Bax and Bcl-2 pathway.

Relevant dose of the environmental contaminant, tributyltin, promotes histomorphological changes in the thyroid gland of male rats

Organotin compounds, such as tributyltin (TBT), are common environmental contaminants and suspected endocrine-disrupting chemicals. Tributyltin is found in antifouling paints, widely used in ships and other vessels. The present study evaluated whether a 15-day treatment with TBT at a dose of 100 ng/kg/day could induce histomorphological changes in the thyroid gland of rats. TBT promoted relevant alterations in the thyroid architecture, being the most relevant histological findings the presence of increased number of small-size follicles in the treated group. In qualitative analyses, colloid vacuolization, papillary budging structures, cystic degeneration and chronic thyroiditis, were observed. Moreover, histomorphometric analysis showed statistically significant changes in the follicular architecture of TBT-treated rats, mainly a decrease in the follicle area (colloid) and an increased epithelial height that resulted in an increased epithelial height/colloid ratio. Augmented collagen deposition was also seen in the thyroids of treated groups. In immunohistochemical (IHC) analyses, the localization of NIS protein was described and a significant increased proliferation index (evaluated by Ki67 positive cells) in the treated group was reported. As an indirect measurement of oxidative stress, mitochondrial protein SDHA was also analyzed by IHC analysis. Although the cytoplasmic expression of SDHA was observed in both groups, the staining intensity score was higher in TBT-treated group. Our results suggest that besides causing histomorphological changes, environmental relevant dose of TBT treatment can also induce oxidative alterations.

Alterations of thyroidal status in brain regions and hypothalamo-pituitary-blood-thyroid-axis associated with dopaminergic depletion in substantia nigra and ROS formation in different brain regions after MPTP treatment in adult male mice

MPTP produces oxidative stress, damages niagrostriatal dopaminergic neurons and develops Parkinsonism in rodents. Due to paucity of information, the thyroidal status in brain regions and peripheral tissues during different post-treatment days in MPTP-induced mice had been executed in the present study. MPTP depleted tyrosine hydroxylase protein expressions that signify the dopaminergic neuronal damage in substantia nigra. MPTP elevated ROS formation differentially in brain regions (cerebral cortex, hippocampus, substantia nigra) with maximal elevation at hippocampus. The changes in thyroid hormone (T₄ and T₃) levels indicate that brain regions might combat the adverse situation by keeping the levels of thyroid hormones either unchanged or in the elevated conditions in the latter phases (day-3 and day-7), apart from the depletion of thyroid hormones in certain brain regions (T₄ in SN and hippocampus, T₃ in hippocampus) as the immediate (day-1) effects after MPTP treatment. MPTP caused alterations of cellular morphology, RNA:Protein ratio and TPO protein expression, concomitantly depleted TPO mRNA expression and elevated TSH levels in the thyroid gland. Although T₄ levels changed differentially, T₃ levels remained unaltered in thyroid gland throughout the post-treatment days. Results have been discussed mentioning the putative role of T₄ and TSH in apoptosis and/or proliferation/differentiation of thyrocytes. In blood, T₄ levels remained unchanged while the changes in T₃ and TSH levels did not signify the clinical feature of hypo/hyperthyroidism of animals. In the pituitary, both T₄ and T₃ levels remained elevated where TSH differentially altered (elevated followed by depletion) during post-treatment days. Notably, T₄, T₃ and TSH levels did not alter in hypothalamus except initial (day-1) depletion of the T₄ level. Therefore, the feedback control mechanism of hypothalamo-pituitary-blood-thyroid-axis failed to occur after MPTP treatment. Overall, MPTP altered thyroidal status in the brain and peripheral tissues while both events might occur in isolation as well.

Alteration of thyroid hormone signaling triggers the diabetes-induced pathological growth, remodeling, and dedifferentiation of podocytes

Thyroid hormone (TH) signaling is a universal regulator of metabolism, growth, and development. Here, we show that TH-TH receptor (TH-TR) axis alterations are critically involved in diabetic nephropathy-associated (DN-associated) podocyte pathology, and we identify TRα1 as a key regulator of the pathogenesis of DN. In ZSF1 diabetic rats, T3 levels progressively decreased during DN, and this was inversely correlated with metabolic and renal disease worsening. These phenomena were associated with the reexpression of the fetal isoform TRα1 in podocytes and parietal cells of both rats and patients with DN and with the increased glomerular expression of the TH-inactivating enzyme deiodinase 3 (DIO3). In diabetic rats, TRα1-positive cells also reexpressed several fetal mesenchymal and damage-related podocyte markers, while glomerular and podocyte hypertrophy was evident. In vitro, exposing human podocytes to diabetes milieu typical components markedly increased TRα1 and DIO3 expression and induced cytoskeleton rearrangements, adult podocyte marker downregulation and fetal kidney marker upregulation, the maladaptive cell cycle induction/arrest, and TRα1-ERK1/2-mediated hypertrophy. Strikingly, T3 treatment reduced TRα1 and DIO3 expression and completely reversed all these alterations. Our data show that diabetic stress induces the TH-TRα1 axis to adopt a fetal ligand/receptor relationship pattern that triggers the recapitulation of the fetal podocyte phenotype and subsequent pathological alterations.

Thyroid Hormone Signalling: From the Dawn of Life to the Bedside

Thyroid hormone (TH) signalling is a key modulator of fundamental biological processes that has been evolutionarily conserved in both vertebrate and invertebrate species. TH may have initially emerged as a nutrient signal to convey environmental information to organisms to induce morpho-anatomical changes that could maximise the exploitation of environmental resources, and eventually integrated into the machinery of gene regulation and energy production to become a key regulator of development and metabolism. As such, TH signalling is particularly sensitive to environmental stimuli, and its alterations result in fundamental changes in homeostasis and physiology. Stressful stimuli of various origins lead to changes in the TH-TH receptor (TR) axis in different adult mammalian organs that are associated with phenotypical changes in terminally differentiated cells, the reactivation of foetal development programmes, structural remodelling and pathological growth. Here, we discuss the evolution of TH signalling, review evolutionarily conserved functions of THs in essential biological processes, such as metamorphosis and perinatal development, and analyse the role of TH signalling in the phenotypical and morphological changes that occur after injury, repair and regeneration in adult mammalian organs. Finally, we examine the potential of TH treatment as a therapeutic strategy for improving organ structure and functions following injury.

Allylpyrocatechol, isolated from betel leaf ameliorates thyrotoxicosis in rats by altering thyroid peroxidase and thyrotropin receptors

Allylpyrocatechol (APC) was isolated from betel leaf and its possible role in L-thyroxin (L-T4)-induced thyrotoxic rats was evaluated. The disease condition, thyrotoxicosis was confirmed by higher levels of thyroid hormones and low thyrotropin (TSH) in serum. Increased hepatic activities of 5'-mono-deiodinase(5'D1), glucose-6-phospatase (G-6-Pase); serum concentrations of alanine transaminase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase(LDH) and tumour necrosis factor-alpha(TNF-α) were observed in thyrotoxic rats. Hepatic lipid peroxidation(LPO) was also increased and the endogenous antioxidants were depleted in these rats. In western blot analysis thyroid peroxidase expression was found to be reduced, whereas thyrotropin receptor(TSHR) expression was enhanced in thyroid gland of these animals. On the other hand, APC treatment in thyrotoxic rats decreased the levels of serum thyroid hormones, ALT, AST, TNF-α and LDH, as well as hepatic 5' D1 and G-6-Pase activities. However, it increased the serum TSH levels. APC also reduced the hepatic LPO and increased the cellular antioxidants in thyrotoxic rats. However, expression of TSHR was inhibited and TPO was increased by APC. The test compound also improved histological features in both liver and thyroid. Present report appears to be the first one that indicates the positive role of APC in ameliorating T4-induced thyrotoxicosis.

Impacts of resveratrol versus platelet-rich plasma for treatment of experimentally lithium-induced thyroid follicular cell toxicity in rats. A histological and immunohistochemical study

Lithium (Li) is used for the treatment and prophylaxis of mental disorders, associated with many serious hazards. Resveratrol (RSV) has various beneficial therapeutic effects. Platelet-rich plasma (PRP) is a new promising curative tool. This study aimed to assess the impacts of RSV versus PRP on lithium-induced thyroid follicular cell toxicity in adult male rats. Forty-nine adult male rats were divided into four groups: group I: control rats; group II: lithium-treated rats; group III: lithium- and resveratrol-treated rats; group IV: lithium and PRP-treated rats. Thyroid specimens were taken and processed for histological and immunohistochemical methods. Morphometrical studies and statistical analysis were done. Group II showed distorted thyroid follicles, significantly increased collagen fibers, and highly positive P53 immunostaining (P < 0.01). Ultrastructural examination showed dilated rough endoplasmic reticulum and damaged mitochondria. Groups III and IV exhibited significant amelioration of the histological and electron microscopic changes mentioned previously. PRP remedy was more effective than RSV for treatment of Li-induced thyroid follicular cell toxicity.

Effect of Subclinical and Overt Form of Rat Maternal Hypothyroidism on Offspring Endochondral Bone Formation

Maternal hypothyroidism in its overt form affects skeletal development of the offspring, but these data are not available for the subclinical form which is becoming very frequent among pregnant women. We hypothesized that the subclinical form of hypothyroidism in rat dams, infl uences the process of offspring endochondral ossifi cation affecting proliferation and differentiation of chondrocytes, osteoclasts and osteoblasts in pups. Seven-day-old male pups (n=18) derived from control dams and dams treated with a low dose (1.5 mg/L) or high dose (150 mg/L) of propylthiouracil in drinking water during pregnancy and lactation were used. Histomorphometric analysis of pups’ tibia proximal growth plate, expression of mRNA, immunohistochemical and histochemical visualization of extracellular matrix components was performed. The length of the tibia was reduced in hypothyroid pups. Secretion of type 2 and 10 collagens in the subclinical and overt form were lower while the amount of glycosaminoglycans was higher when compared with controls. Down-regulated tartrate resistant acid phosphatase mRNA indicated altered osteoclasts function while lower expression of dentin matrix acid protein-1 mRNA and reduced synthesis of type 1 collagen accentuated a compromised bone formation in the overt form of hypothyroidism. The subclinical form of maternal hypothyroidism had a negative effect on the differentiation of hypertrophic chondrocytes and calcifi ed cartilage removal in 7-day-old pups. In addition, overt hypothyroidism had a negative effect on the proliferation of chondrocytes and deposition of osteoid. Both forms of hypothyroidism resulted in a decrease of tibia length due to changes in growth plate formation.

Interaction between iodine and glucosinolates in rutabaga sprouts and selected biomarkers of thyroid function in male rats

Rutabaga sprouts belong to the Brassicaceae family and may exert a negative influence on thyroid function, because they are a rich in glucosinolates. These sprouts are also valuable source of iodine (6.5 ± 0.6 μg/100 g of fresh weight). Sprouts were tested in a long-term experiment with young male rats as an element of their diet, combined with two models of hypothyroidism, the first - deficit of iodine and the second - sulfadimethoxine ingestion as a pharmacological agent caused inhibition of thyroid peroxidase. Evaluations were performed for the serum TSH and thyroid hormones together with analyzes of thyroid histopathology, cytosolic glutathione peroxidase (GPX1), thioredoxin reductase in the thyroid, plasma GPX3 and CAT, erythrocyte GPX1. Rutabaga sprouts' intake by healthy rats did not cause any harmful effect on their health, including thyroid function. For animals with hypothyroidism, rutabaga sprouts enhanced the adverse effect of iodine deficiency or ingestion of sulfadimethoxine on the organism. According to the results obtained for young male rats thyroid function, the interpretation of data for human exposure to rutabaga sprouts has to be avoided. Furthermore, unless new scientific data confirms a lack of the negative effect of brassica sprouts on thyroid function in human, they should not be excluded from the group of goitrogenic products.