Rat Thyroid Tissue Research Articles

Dynamics of morphological parameters of the thyroid gland in hypertensive SHR rats upon administration of propylthiouracil.

Background. The main clinical manifestations of thyroid gland (TG) diseases are associated with the influence of thyroid hormones on the cardiovascular system. At the same time, hypothyroidism as well as hyperthyroidism increase the risk of arterial hypertension. Based on this, the development of an experimental model that combines thyroid pathology and hypertension is relevant. From this point of view, the hypertensive SHR rats is a valuable object of study, since the course of arterial hypertension in these animals corresponds to the signs of human hypertension. Objective. Study of the dynamics of the morphological parameters of the thyroid gland in SHR rats with prolonged administration of propylthiouracil (PTU). Methods. Female SHR rats were used in the experiments; drinking water contained a 0.1% solution of PTU. TG was taken on the 17th, 25th, 31st, 39th and 47th days of the experiment, subjected to histological examination and staining with hematoxylin / eosin according to standard methods. We analyzed the average height of the follicular epithelium, the average follicle area, the nuclear cytoplasmic ratio (NCR) of thyrocytes, the ratio of the number of thyrocytes to fibroblasts per 50 μm2 (T/FB). Results. It was established that the height of the epithelium, NCR, and the area of the follicles change irregularly during the intake of PTU: at first, fluctuations of indicators are observed, and starting from 31st day they are stabilized. In general, after 47 days of receiving PTU, the average height of the follicular epithelium increased by 0.7 μm, the average area of the follicles – by 182 μm2, and NCR – by 0.11. In the stroma of the gland, activation of fibroblast proliferation was observed as evidenced by a decrease in the T/FB ratio from 2.87 to 0.54. Conclusion. When using a solution for drinking with 0.1% PTU for 47 days characteristic changes of hypertrophy and hyperplasia are observed in the thyroid tissue of hypertensive SHR rats. Stabilization of morphological parameters is observed after 30 days of taking PTU.

Гистопатологические характеристики ткани щитовидной железы крыс после криовоздействия

Гистопатологические характеристики ткани щитовидной железы крыс после криовоздействия

Expression, Localization, and Regulation of the Sodium Bicarbonate Cotransporter NBCe1 in the Thyroid.

The intrafollicular space of thyroid follicles is the storage compartment for thyroid hormones. Its pH has been established at around 7.6 at least after thyrotropin (TSH) stimulation. This alkaline intrafollicular pH is thought to be critical for iodide coupling to thyroglobulin and internalization of iodinated thyroglobulin. At least in mice, this alkalinization requires the expression of pendrin (Slc26a4) within the apical membrane, and a lack of pendrin results in acidic follicular lumen pH. Yet, the mechanism importing HCO3- into the cytoplasm is unknown. This study investigated whether the rather ubiquitous sodium bicarbonate cotransporter NBCe1 (SLC4A4) might play this role. It also examined which variant was expressed and where it was localized in both rat and human thyroid tissue. Lastly, the dependence of its expression on TSH was studied. Reverse transcription polymerase chain reaction, immunofluorescence, and Western blotting were used to test whether TSH stimulated NBCe1 protein expression in vivo. Subcellular localization of NBCe1 was performed using immunofluorescence in both rat and human thyroid. Cultured thyroid cells were also used to attempt to define how TSH affects NBCe1 expression. Only transcripts of the NBCe1-B variant were detected in both rat and human thyroid. Of interest, NBCe1-C was not detected in human tissues, not even in the brain. On immunofluorescence microscopy, the immunostaining of NBCe1 mainly appeared in the basolateral membrane upon stimulation with TSH. This TSH induction of basolateral membrane expression of NBCe1 protein was confirmed in vivo in rat thyroid and in vitro on human thyroid slices. This study demonstrates the expression of the sodium bicarbonate cotransporter NBCe1-B in rat and human thyroid. Additionally, the data suggest that TSH blocks the degradation of NBCe1 protein by trafficking it to the basolateral membrane. Hence, TSH increases NBCe1 half-life without increasing its synthesis.

Cytotoxic effects of Euterpe oleraceae fruit oil (açaí) in rat liver and thyroid tissues

Euterpe oleracea Mart., Arecaceae, fruit (açaí) presents considerable potential for the development of new medicines due to its phytochemical composition and antioxidant activity. More recently, special attention has been given to the pharmacological potential of the fruit's oil. This study analysed the histological and histochemical effects of different dosages of açaí oil on rat's liver and thyroid cells, in order to evaluate its cytotoxic potential after administration for consecutive days. Male Wistar rats were treated with the açaí oil by gavage at doses of 30, 100 and 300mg/kg, for 14 days, within a 24h interval. Liver and thyroid fragments were collected for histology (hematoxylin and eosin) and histochemistry analysis (blue of Nilo (lipids), Baker (lipids), bromophenol blue (protein), PAS (polysaccharides)). The results showed that animals exposed to açaí oil presented alterations in the liver cells, where the integrity of the liver tissue was increasingly lost as the açaí oil doses increased. Nuclear pyknosis was observed in several hepatocytes, evidencing the occurrence of cell death. Alteration in the amount of lipids, polysaccharides, vacuoles in the cytoplasm, and proliferation of Kupffer cells were observed in histochemical analyzes. As for the thyroid of the treated rats, alterations were observed in the size of the follicular lumen and also in the connective tissue found between the follicles. Under the experimental conditions employed in the present study, the cytotoxicity observed in this work is worrying, specially considering the liver, when frequent or continuous damage could lead pathological disorders in this organ.

Effects of total thyroidectomy on growth factor, apoptosis factor and immunomodulatory factor of thyroid carcinoma in rats

Objective To study effects of total thyroidectomy on growth factor, apoptosis factor and immunomodulatory factor in rats with thyroid carcinoma. Methods Sixty male SD rats were randomly divided into three groups: model group, operation group and negative control group. The animal model of thyroid carcinoma was established, and the three groups were treated with the same amount of normal saline for 8 weeks after total thyroidectomy. The expression of vascular endothelial growth factor (VEGF), soluble Fas receptor (sFas) and soluble Fas receptor ligand (sFasL) in rat thyroid tissue was detected by Western blotting. The thyroid gland in rats was determined by reverse transcriptase-polymerase chain reaction (RT-PCR). Interleukin (IL)-1 β, IL-6 and tumor necrosis factor-α (TNF-α) were detected by enzyme linked immunosorbent assay (ELISA). Results The results of Western blotting and RT-PCR showed that the expression levels of VEGF, sFas and sFasL proteins, VEGF, sFas and sFasL mRNA, TNF-α, IL-1β, and IL-6 in model group and operation group were significantly higher than in the negative control group (P=0.000). As compared with the model group, the expression levels of VEGF, sFas and sFasL proteins, VEGF, sFas and sFasL mRNA, TNF-α, IL-1β, and IL-6 were significantly decreased in the operation group (P=0.000). Conclusion Total thyroidectomy can remove thyroid cancer tissues and inhibit the growth and metastasis of thyroid carcinoma, which is related to the down-regulation of the expression of growth factor, apoptosis factor and immunomodulatory factor. Key words: Total thyroidectomy; Thyroid carcinoma; Growth factor; Immunoregulatory factor

Receptor Cross Talk and Interplay between Melatonin and Ovarian Thyroid Axis in a Letrozole Induced Polycystic (Pco) Rat

The objective of present study was to establish the interrelationship between thyroid and melatonin during anovulatory/letrozole induced polycystic ovarian condition on female Wister rats. Rats were procured and after acclimatization 20 rats were divided in 4 groups with 5 rats in each. They were divided as Control, Letrozole induced PCO rat (1 mg/kg BW/d), and melatonin alone (200 μg/100 g BW/d). The experiment was conducted for the duration of 28 d. Assessment of gravimetric, hormonal profile and thyroid histology and relative expression of MT1, MT2, and ERα, (thyroid, ovary) Dio2, TRα (Ovary) done followed by standard protocol. Histological observation showed shrinkages in thyroid follicles in PCO rats however exogenous melatonin maintained the cellular architecture and normal thyroid weight. PCO rats showed significantly high circulating testosterone but significant decreased in estrogen and progesterone level. Circulatory gonadotropins (LH, FSH) were noted significantly high in PCO rats. Melatonin injection to the PCO rats however reversed to the control level and restored. Circulatory TSH level in PCO rats were noted suppressed where as T3 and T4 were non-significantly increased suggesting a reciprocal relation between melatonin and thyroxine. Thyroid tissue of PCO rats expressed MT1 and MT2 in way alternate and opposite way being MT1 as up regulated whereas down regulation of MT2. Ovarian tissue of PCO rats showed reverse receptor expression to that of thyroid tissue being MT1 down regulated and MT2 was noted unregulated. Parallel relation was noted between ERα and TRα receptor expression in thyroid and ovarian tissue respectively. PCO rats resulted in up regulation of Dio2, receptor expression in a non-significant manner. Therefore, present finding suggests a fine interplay and cross talk via melatonin its two receptor MT1 , MT2 with ERα, TRα, and Dio2 thyroid and ovarian tissue as the case between ovarian thyroid axis hence maintaining a physiological trade-offs between theses gland with a tonic regulation to maintain melatonin and thyroid homeostasis during polycystic pathogenicity.

Effects of Long-Term In Vivo Exposure to Di-2-Ethylhexylphthalate on Thyroid Hormones and the TSH/TSHR Signaling Pathways in Wistar Rats.

Di-(2-ethylhexyl)phthalate (DEHP) was a widely used chemical with human toxicity. Recent in vivo and in vitro studies suggested that DEHP-exposure may be associated with altered serum thyroid hormones (THs) levels, but the underlying molecular mechanisms were largely unknown. To explore the possible molecular mechanisms, 128 Wistar rats were dosed with DEHP by gavage at 0, 150, 300, and 600 mg/kg/day for 3 months (M) and 6 M, respectively. After exposure, expression of genes and proteins in the thyroid, pituitary, and hypothalamus tissues of rats were analyzed by Q-PCR and western blot, while the sera and urine samples were assayed by radioimmunoassay and ELISA. Results showed that serum THs levels were suppressed by DEHP on the whole. DEHP treatment influenced the levels of rats’ thyrotropin releasing hormone receptor (TRHr), Deiodinases 1 (D1), thyroid stimulating hormone beta (TSHβ), sodium iodide symporter (NIS), thyroid stimulating hormone receptor (TSHr), thyroperoxidase (TPO), thyroid transcription factor 1 (TTF-1), and thyroglobulin (TG) mRNA/protein expression in the hypothalamus-pituitary-thyroid (HPT) axis and decreased urine iodine. Taken together, observed findings indicate that DEHP could reduce thyroid hormones via disturbing the HPT axis, and the activated TSH/TSHR pathway is required to regulate thyroid function via altering TRHr, TSHβ, NIS, TSHr, TPO, TTF-1 and TG mRNA/protein expression of the HPT axis.

Comparative study of the primary cilia in thyrocytes of adult mammals.

Since their discovery in different human tissues by Zimmermann in 1898, primary cilia have been found in the vast majority of cell types in vertebrates. Primary cilia are considered to be cellular antennae that occupy an ideal cellular location for the interpretation of information both from the environment and from other cells. To date, in mammalian thyroid gland, primary cilia have been found in the thyrocytes of humans and dogs (fetuses and adults) and in rat embryos. The present study investigated whether the existence of this organelle in follicular cells is a general event in the postnatal thyroid gland of different mammals, using both immunolabeling by immunofluorescence and electron microscopy. Furthermore, we aimed to analyse the presence of primary cilia in various thyroid cell lines. According to our results, primary cilia are present in the adult thyroid gland of most mammal species we studied (human, pig, guinea pig and rabbit), usually as a single copy per follicular cell. Strikingly, they were not found in rat or mouse thyroid tissues. Similarly, cilia were also observed in all human thyroid cell lines tested, both normal and neoplastic follicular cells, but not in cultured thyrocytes of rat origin. We hypothesize that primary cilia could be involved in the regulation of normal thyroid function through specific signaling pathways. Nevertheless, further studies are needed to shed light on the permanence of these organelles in the thyroid gland of most species during postnatal life.

Morphological and functional changes in pituitary-thyroid axis following prolonged exposure of female rats to constant light.

Light regulates numerous physiological functions and synchronizes them with the environment, in part by adjusting secretion of different hormones. We hypothesized that constant light (CL) would disturb pituitary-thyroid axis. Our aim was to determine morphological and functional changes in this endocrine system in such extreme conditions and, based on the obtained results, to propose the underlying mechanism(s). Starting from the thirtieth postnatal day, female Wistar rats were exposed to CL (600 lx) for the following 95 days. The controls were maintained under the regular laboratory lighting conditions. After decapitation, pituitaries and thyroids were prepared for further histomorphometric, immunohistochemical, and immunofluorescence examinations. Concentration of thyroid stimulating hormone (TSH), total T4 and T3 (TH) were determined. Thyroid tissue of light-treated rats was characterized by microfollicular structure. We detected no change in total thyroid volume, localization and accumulation of thyroglobulin, thyroid peroxidase, and sodium-iodide symporter in the follicular epithelium of CL rats. The volume of follicular epithelium and activation index were increased, while volume of the colloid and serum levels of TH decreased. In the pituitary, the relative intensity of TSH β-immunofluorescence signal within the cytoplasm of thyrotrophs increased, but their average cell volume and the relative volume density decreased. Serum TSH was unaltered. We conclude that exposure of female rats to CL induced alterations in pituitary-thyroid axis. Thyroid tissue was characterized by microfollicular structure. Serum TH levels were reduced without accompanying increase in serum TSH. We hypothesize that increased secretion and clearance of TH together with unchanged or even decreased hormonal synthesis, resulted in decreased serum TH levels in CL group. We assume this decrease consequently led to increased synthesis and/or accumulation of pituitary TSH. However, decreased average TSH cell volume and relative volume density, together with unchanged serum TSH, point to additional, negative regulation of thyrotrophs.

Pistacia chinensis: a potent ameliorator of CCl₄ induced lung and thyroid toxicity in rat model.

In the current study protective effect of ethanol extract of Pistacia chinensis bark (PCEB) was investigated in rats against CCl4 induced lung and thyroid injuries. PCEB dose dependently inhibited the rise of thiobarbituric acid-reactive substances, hydrogen peroxide, nitrite, and protein content and restored the levels of antioxidant enzymes, that is, catalase, peroxidase, superoxide dismutase, glutathione-S-transferase, glutathione reductase, glutathione peroxidase, γ-glutamyl transpeptidase, and quinone reductase in both lung and thyroid tissues of CCl4 treated rats. Decrease in number of leukocytes, neutrophils, and hemoglobin and T3 and T4 content as well as increase in monocytes, eosinophils, and lymphocytes count with CCl4 were restored to normal level with PCEB treatment. Histological study of CCl4 treated rats showed various lung injuries like rupture of alveolar walls and bronchioles, aggregation of fibroblasts, and disorganized Clara cells. Similarly, histology of CCl4 treated thyroid tissues displayed damaged thyroid follicles, hypertrophy, and colloidal depletion. However, PCEB exhibited protective behaviour for lungs and thyroid, with improved histological structure in a dose dependant manner. Presence of three known phenolic compounds, that is, rutin, tannin, and gallic acid, and three unknown compounds was verified in thin layer chromatographic assessment of PCEB. In conclusion, P. chinensis exhibited antioxidant activity by the presence of free radical quenching constituents.

Proteasomes on thyroid tissue allotransplantation under induction of donor specific tolerance in rats

The proteasomes in the liver of August rats (RT1C) were investigated 30 days after the allotransplantation of Wistar rat (RT1u) thyroid tissue under renal capsule with/without induction of donor specific tolerance by donor splenocyte intraportal administration. The level of the total proteasome pool, immune proteasomes containing the LMP2 and/or LMP7 subunits, proteasome 19S- and 11S-regulators was defined. The intact and sham-operated August rats were used as control groups. The level of all immune proteasome forms and 11S regulator increased while the level of the total proteasome pool and 19S regulator decreased in the liver of experimental animals compared to the control groups that indicated changes of liver functional state after transplantation. The 19S/11S ratio increased in the liver of non-tolerated rats compared to tolerated animals. In the liver of tolerated rats with survived transplants, the quantity of mononuclear cells, expressing the immune subunit LMP2, greatly increased in comparison with control and non-tolerated animals. Study of the survived transplants showed the increase of the ratio of LMP2/LMP7 immune subunits and 19S/11S regulators in them compared to the tissue replacing the rejected transplants. In the control intact thyroid tissue, the immune proteasomes were almost not revealed, while 19S/11S ratio was maximal. Thus, the development of the immune reaction or its suppression is accompanied by change of the balance between different proteasome forms. The immune subunit LMP7 and 11S regulator are connected with the response against donor tissue. On the contrary, the immune subunit LMP2 and 19S regulator are likely to be important for the immune tolerance development and survived tissue functioning. The low content of the immune proteasomes in the follicle cells was found by immunofluorescence assay. The formation of antigens for major histocompatibility complex class I molecules was impaired by low immune proteasome content that led to immunological tolerance to hormone-producing follicle cells.

Catechin induced modulation in the activities of thyroid hormone synthesizing enzymes leading to hypothyroidism

Catechins, the flavonoids found in abundance in green tea, have many beneficial health effects such as antioxidative, anticarcinogenic, anti-inflammatory, antiallergic, and hypotensive properties. However, flavonoids have antithyroid/goitrogenic effect, although less information is available about the effect of pure catechin on thyroid physiology. The present investigation has been undertaken to explore the effect of catechin administration on thyroid physiology in rat model. For the in vivo experiment catechin was injected intraperitoneally (i.p.) at doses of 10, 20 and 30 mg/kg body to male albino rats for 15 and 30 days, respectively, and thyroid activities were evaluated with respect to determination of serum levels of thyroid hormones, thyroid peroxidase, 5'-deiodinase I (5'-DI), and Na(+), K(+)-ATPase activities that are involved in the synthesis of thyroid hormone. Catechin decreased the activities of thyroid peroxidase and thyroidal 5'-deiodinase I, while Na(+), K(+)-ATPase activity significantly increased in dose-dependent manner; substantial decrease in serum T3 and T4 levels coupled with significant elevation of serum TSH were also noted. Histological examinations of the thyroid gland revealed marked hypertrophy and/or hyperplasia of the thyroid follicles with depleted colloid content. In in vitro study, short-term exposure of rat thyroid tissue to catechin at the concentrations of 0.10, 0.20, and 0.30 mg/ml leads to decrease in the activities of thyroid peroxidase and 5'-deiodinase I, while the activity of thyroidal Na(+), K(+)-ATPase remains unaltered even at high concentration of catechin treatment. The present study reinforces the concept that catechin, tea flavonoids possess potent antithyroid activity as evidenced from in vivo and in vitro studies.

Protective effects of Sonchus asper (L.) Hill, (Asteraceae) against CCl(4-)induced oxidative stress in the thyroid tissue of rats.

BackgroundSonchus asper (L.) Hill, (Asteraceae) is used in Pakistan as a traditional (“folk”) medicine for the treatment of hormonal disorders and oxidative stress. The present study was aimed to evaluate the efficacy of Sonchus asper (L.) Hill, (Asteraceae) methanolic extract (SAME) on hormonal dysfunction in thyroid tissue after carbon tetrachloride (CCl4)-induced oxidative stress.MethodsTo examine the effects of SAME against the oxidative stress of CCl4 in thyroid tissue, 30 male albino rats were used. Protective effects of SAME were observed on thyroid hormonal levels, activities of antioxidant enzymes, lipid peroxidation (TBARS) and DNA damage.ResultsTreatment with CCl4 significantly (P<0.01) reduced the levels of T3 and T4 and increased TSH levels. CCl4 exposure in rats reduced the activities of antioxidant enzymes but increased lipid peroxidation and DNA damage. Co-administration of SAME significantly (P<0.01) improved these alterations with respect to hormonal levels, activities of antioxidant enzymes and lipid peroxidation close to those seen in control rats.ConclusionThese results suggest that SAME can protect thyroid tissue against oxidative damage, possibly through the antioxidant effects of its bioactive compounds.

Poly-L-lactic acid and poly-ε-caprolactone as biomaterials for ex-situ bioengineering of the rat thyroid tissue

We are currently developing innovative methodologies for rapid prototyping of threedimensional (3D) replicas of the vascular matrix of soft and hard tissue organs, primarily the thyroid and bones, with the intent of obtaining organomorphic scaffolds for their ex situ reconstruction (1, 2). To identify biocompatible materials suitable for this application, we have studied the effect of poly-L-lactic acid (PLLA) and poly-e-caprolactone (PCL) on survival, adhesion and hormonal secretory activity of primary rat thyroid cells. Sprague- Dawley male rats (225-250 g) were used as thyroid donors. After penthobarbital anesthesia rats were thyroidectomised, thyroids surgically excised, and primary cells prepared using enzymatic breaking. After 72 hs in standard monolayer culture, cells were trypsinized and seeded (20 x103 / cm2) onto microporous scaffold sheets. Biomaterial scaffolds were prepared using either 3.5-5% PLLA (Lacea H100E, Mistui Chemicals) in anydrous dichloromethane / amylene (Sigma) or 3% PCL (Aldrich) in anydrous tetrahydrofurane / BHT (Aldrich). Solutions were dropped onto a wet glass support, and let polymerize as a thin layer at 25°C in the absence of forced air flow. Pattern of polymerization was assessed with thermogravimetry. Cells were let grow on biomaterials up to 8 days. Single biomaterial sheets without cells, and standard multiwell cultures were used as controls. Every 2 days, percentage of viable cells was assessed using a count chamber and Trypan blue exclusion, whereas morphology of growing cells was analyzed using a scanning electron microscopy (SEM) technique without critical point drying. Culture supernatants were collected every 48 hs, and free forms of thyroid hormone (FT3 and FT4) assessed with chemiluminescent immunoassays. PLLA and PCL scaffold sheets exhibited a quite homogeneous thickness (10-12 μm), a repetitive and regular pore geometry, and a crystalline pattern of polymerization. Both biomaterials promoted survival, adhesion and proliferation of primary thyroid elements. Secretion of FT3 and FT4 was variably maintained during the culture period, and resulted statistically higher with respect to monolayer cultures on standard multiwells. Our results indicate that PLLA and PCL are suitable for growth and differentiation of adult rat thyroid cells in culture, and suggests that they might be exploited as bioerodible materials for rapid prototyping of vascular-like, organomorphic scaffolds.

Ghrelin potentiates TSH-induced expression of the thyroid tissue-specific genes thyroglobulin, thyroperoxidase and sodium-iodine symporter, in rat PC-Cl3 Cells

Ghrelin is a 28-amino-acid peptide that stimulates pituitary growth-hormone secretion and modulates food-intake and energy metabolism in mammals. It is mainly secreted by the stomach, but it is also expressed in many other tissues such as cartilage or the thyroid gland. In the present study we have analyzed by RT-PCR and using immunohistochemistry and immunofluorescence the expression and tissue distribution of ghrelin and its functional receptor (GHS-R type 1α) in thyroid cell-lines and in normal and pathological rat thyroid tissue. Additionally, by measuring the incorporation of BrdU, we have investigated if, as previously noted for FRTL-5 cells, ghrelin enhances the proliferation rate in the PC-Cl3 rat-thyrocyte cell-line. Finally, we have determined the stimulatory effect of ghrelin on TSH-induced expression of the tissue-specific key genes involved in the synthesis of thyroid hormone: thyroglobulin, thyroperoxidase and sodium–iodine symporter. Our data provide direct evidence that C-cell secreted ghrelin may be involved in the paracrine regulation of the thyroid follicular cell function.

The effect of iodine excess on bone metabolism in experimental autoimmune thyroiditis rats

Objective To explore the effect of iodine excess on bone metabolism in experimental autoimmune thyroiditis (EAT) rats. Methods We selected 36 female Lewis rats with body weight of (131 ± 15)g,and divided them into 3 groups randomly: control group, EAT group and EAT + high iodine group, assuring 12 rats in every group. These rats were fed fodder with different concentration of iodine(0.9,0.9, 18.0 mg/kg), and rats in EAT group and EAT + high iodine group were immunized with pig thyroglobulin(pTG) and complete Freund's adjuvant(CFA) to create EAT model. After two weeks, the pathological changes of the thyroid tissues were observed,and the serum thyroid autoantibody[thyroglobulin antibody(TGAb) and thyroid microsomal antibody(TMAb)], the thyroid hormone levels[triiodo thyronine(T3) and thyrine(T4)] and some relevant data of bone metabolism[bone gla protein (BGP), tartrate-resistant acid phosphatase (TRAP), C-terminal propeptide of type Ⅰ procollagen (PICP),C-terminal telopeptide of type Ⅰ collagen (ICTP), insulin-like growth factor- 1 ( IGF- 1 ), osteoprotegerin (OPG) and receptor activator of NF-κB ligand (RANKL)] were measured. Results Inflammatory cell infiltration and local follicular structural damage were observed in the thyroid tissues of EAT rats in EAT group and EAT + high iodine group, and the pathological changes of EAT + high iodine group were mainly thyroid follicular expansion and integration. The level of serum TGAb, TMAb, T3 and T4 of EAT rats in EAT group and EAT + high iodine group[ (63.01 ± 12.36)%, (60.62 ± 11.24)%, (3.78 ± 1.43), (125.12 ± 16.00)pmol/L and (75.00 ± 15.44)%,(72.15 ± 15.00)%, (3.69 ± 0.91 ), (149.40 ± 20.67)pmol/L] were higher than those of the control group[ (4.47 ±1.04)%, (5.73 ± 1.01 )%, (0.75 ± 0.12), (76.91 ± 9.30)pmol/L, all P ＜ 0.05], and the level of serum TGAb,TMAb and T4 of EAT rats in EAT + high iodine group were higher than those of the EAT group(all P ＜ 0.05).The level of serum BGP, PICP and IGF- 1 in EAT group[ ( 1.70 ± 0.31 ), ( 11.31 ± 1.52) μg/L, (0.31 ± 0.06 ) mg/L]were lower than those of the control group[ (8.60 ± 0.33), (14.28 ± 3.10)μg/L, (1.16 ± 0.02)mg/L, all P ＜0.05], and the level of serum TRAP, ICTP, OPG and RANKL[ ( 19.88 ± 3.60)ng/L, (2.43 ± 0.82), (22.36 ± 2.80),( 1.35 ± 0.23 )μg/L] were higher than those of the control group[ ( 14.57 ± 3.56)ng/L, (0.50 ± 0.20), (1.61 ± 0.34),(0.10 ± 0.02)μg/L, all P ＜ 0.05]; compared with EAT group, the level of PCIP and OPG in EAT + high iodine group [ (8.03 ± 1.84), ( 16.80 ± 3.79)μg/L] were obviously decreased(all P ＜ 0.05). Conclusions The reinforcement of differentiation and maturation of osteoblast in the EAT rats results in the increasing of bone resorption. The activity of osteoblast and osteoclast of the EAT rats are inhibited by excessive iodine, showing a low conversion-type osteoporosis. Key words: Iodine; Thyroiditis, autoimmune; Bone metabolism; Osteoblasts; Osteoclasts

Electric and magnetic fields do not modify the biochemical properties of FRTL-5 cells

Electric and magnetic fields (EMF) might be involved in human disease and numerous research and scientific reviews have been conducted to address this question. In particular thyroid structural and functional alterations caused by various forms of non-ionizing radiation have been described. The aim of this study was to analyze the possible effects of EMF on thyroid, in particular we analyzed the effects caused by a GSM (Global System for Mobile Communications) signal (900 MHz) on cultured thyroid cells (FRTL- 5). The experimental setup was designed in order to expose samples to a radiofrequency wave in well-controlled conditions. We used the FRTL-5 cell line, an epithelial monoclonal continuous cell line derived from Fisher rat thyroid tissue growing as monolayer, expressing the TSH receptor and the sodium-iodide symporter (NIS). FRTL-5 were subsequently irradiate for 24, 48, and 96 h with EMF (800-900 MHz, power-frequency of mobile communication systems) and iodide uptake and cAMP production were measured. The irradiation of cells with EMF at 900 Mhz for 24, 48, and 96 h did not influence the level of cAMP production and was not able to modify iodide accumulation in FRTL- 5 cells with respect to basal conditions. In conclusion, EMF do not seem to be able to interfere with the biochemical properties of FRTL-5 cells in vitro.

Functional expression of SLC15 peptide transporters in rat thyroid follicular cells

Peptide transport and expression of SoLute Carrier 15 (SLC15) peptide transporters was assessed in rat thyroid tissue and a rat thyroid cell line (PC Cl3 cells). Peptide transport was studied by monitoring the uptake of the fluorophore-conjugated dipeptide beta-Ala-Lys-N(epsilon)-7-amino-4-methyl-coumarin-3-acetic acid (Ala-Lys-AMCA). Expression of SLC15-specific mRNA transcripts was analyzed by RT-PCR. Of the two SLC15 transporters expressed in thyroid follicular cells, namely PEPT2 (SLC15A2) and PHT1 (SLC15A4), only PEPT2 was involved in peptide transport at the plasma membrane, with PHT1 most likely being intracellular. Interestingly, at the mRNA level PEPT2 was up-regulated under TSH stimulation. These findings represent the first evidence that peptide transport occurs in thyroid follicular cells. SLC15 transporters could participate to recycling of peptides derived from extracellular and lysosomal thyroglobulin proteolysis, both essential steps for thyroid hormone synthesis.

Effects of Kang-Jia-Wan, a Chinese medicinal herb officinal, on apoptosis induction in goiter of rats

Ethnopharmacological relevance Kang-Jia-Wan (KJW), a traditional Chinese herbal medicine, is widely used to treat goiter in the clinics in China. Aim The mechanisms by which KJW treats goiter are unclear. It is known that insufficient apoptosis of thyrocytes is involved in the formation of goiter. Here, we investigated whether KJW could induce apoptosis in goiter of rats given methimazole (MMI). Materials and methods Fifty-six Wistar rats were randomly separated into four groups: normal, MMI, MMI + low-dose KJW and MMI + high-dose KJW. Except for the normal group (20 rats), all groups (each with 12 rats) were given 0.04% (w/v) MMI in their drinking water. One week later, the rats in MMI + low- and high-dose KJW groups were orally supplemented with KJW at 250 mg/kg d −1 and 1000 mg/kg d −1, respectively. Results After KJW treatment for 12 weeks, the relative thyroid weight (mg/100 g body weight) of the MMI + high-dose KJW group decreased significantly. Features of apoptosis were also apparent in thyroid tissues of rats given KJW treatment. Importantly, KJW markedly increased the caspase-3 and Fas protein expression, in a dose-dependent manner, in the thyroid specimens. Conclusions These results showed that KJW played a therapeutic role via apoptosis induction in the goitrous glands.

Ultrastructural changes in rat thyroid tissue after acute organophosphate poisoning and effects of antidotal therapy with atropine and pralidoxime: A single-blind, ex vivo study

Background: Organophosphate (OP) insecticides are widely used in both agricultural and landscape pest control, and the potential for human exposure to these compounds is significant. Objectives: The aims of this study were to investigate the effects of acute poisoning with the OP methamidophos and the effects of antidotal therapy with atropine and pralidoxime on rat thyroid tissue ultrastructure. Methods: In this single-blind, ex vivo study, male Wistar albino rats weighing 220 to 230 g were divided into 4 treatment groups. Group 1 received a median lethal dose of methamidophos (30 mg/kg) via oral gavage. Group 2 received saline via oral gavage and served as the control group for group 1. Group 3 received methamidophos (30 mg/kg) via oral gavage, and after 8 minutes atropine 0.05 mg/kg and pralidoxime chloride (2-FAM) (40 mg/kg) were administered intraperitoneally (IP). Atropine was titrated to reverse signs of cholinergic excess. Group 4 received saline via oral gavage followed by IP injections and served as the control for group 3. Rat thyroid tissues were examined using electron microscopy, and the histologic changes were examined by a histopathologist who was blinded to treatment. All rats were euthanized by intracardiac blood collection. The rats in groups 1 and 2 were euthanized 8 minutes after treatment. The rats in groups 3 and 4 were euthanized 96 hours after treatment. Results: Thirty-four male rats (aged 16 weeks) were included in the study. The rats were grouped accordingly: group 1 (n = 10); group 2 (n = 7); group 3 (n = 10); and group 4 (n = 7). The mean (SD) pseudocholinesterase (FCE) activity was significantly lower in the methamidophos-treated rats (group 1) compared with the corresponding control group (group 2) (32.6 [17.0] vs 579.4 [59.0] U/L, respectively; P < 0.001). PCE activity was significantly higher in rats treated with atropine and 2-PAM (group 3) (392.5 [39.4] U/L; P < 0.001) compared with those not receiving antidotal therapy (group 1). Group 1 experienced changes in thyrocytes and organelles that were not detected in the antidote-treated rats in group 3. These changes included follicular cell nuclei exhibiting an increase in chromatin content, pyknotic nuclei, mitochondrial degeneration, dilated granular endoplasmic reticulum cisternae, reduced microvilli, and intraluminal cellular debris. Within follicular cells, formation of vacuoles filled with fine granular material was noted. Conclusion: Acute OP poisoning was associated with histopathologic effects in rat thyroid tissue that appeared to be mitigated by antidotal therapy in this small animal study. More extensive studies using immunohistochemical methods are needed.