Number Of Follicular Cells Research Articles

Protective Effect of Selenium and Zinc Against Dehp Induced Toxicity in the Thyroid Gland of Rats

Objective: To compare the efficacy of Selenium and Zinc in improving histological features on DEHP-induced toxicity in the thyroid gland of rats.
 Design of study: Laboratory based experimental study.
 Place and Duration of Study: Anatomy Department of Islamic International Medical College with the National Institute of Health (NIH), Islamabad Pakistan cooperation from Sep 2019 to Sep 2020.
 Methodology: Forty, eight weeks old rats were divided into four groups, each containing ten male rats. In control, Group-A rats were on the standard diet. In Group-B, rats were given orally 500mg/kg/day DEHP. In Group-C rats were given 500mg/kg/day DEHP and 1mg/kg/day Selenium orally. In Group-D rats were given 500mg/kg/day DEHP and 5mg/kg/day Zinc orally. After 28 days, rats were dissected, and the thyroid gland was removed. Histological parameters, vacuolization and number of follicular cells were observed with H and E stining among control and experimental groups.
 Results: In Group-B, 50% of rats showed severe vacuolization. In Group-C, 60% of rats showed minimal vacuolization. In Group- D, 40% of rats showed minimally, and 40% of rats showed mild vacuolization. Among quantitative parameters, the number of follicular cells was conserved more by Selenium than Zinc.
 Conclusion: Selenium and Zinc have a protective effect on thyroid histological changes caused by DEHP, but Selenium shows better conservation than zinc on thyroid histology.

Thyroid Gland Examination for Thyroid Nodule through Free Hand Fine Needle Aspiration Cytology (FNAC) Versus Ultrasound Guided Core Sampling

Objective: To compare the free hand fine needle aspiration cytology versus ultrasound guided core sampling for thyroid nodule examination in thyroid gland. Study Design: Retrospective study Place and Duration of Study: Department of Surgery Unit-2, Ghulam Muhammad Mahar Medical College Hospital Sukkur from 1st January 2016 to 31st December 2021. Methodology: One hundred patients were divided in two groups. Group A had 50 patients who undergo ultrasonography through Doppler scanning while Group B had equal number of 50 patients which underwent free hand fine needle aspiration cytology. The clinical details were noted and graded as un-satisfactory or lacking follicular cells or else having <6 groups epithelial cells or having sufficient number of follicular cells. Results: The mean age was 31.5±11.8 years and majority of the patients were females 54% in comparison with 46% males. Insufficient cytopathologic cells were noticed in 18% US guided thyroidal nodule examination while similar insufficiency was seen in 44% fine needle aspiration cytology examination. The adequate cytopathological cells were noticed in 82% Ultrasounds while same was only seen in 56% fine needle aspiration cytology. Conclusion: Ultrasound guided core sampling has presented higher adequate cytology cases in comparison to free hand fine needle aspiration cytology cases. Key words: Fine needle aspiration cytology, Ultrasonography, Thyroid nodule

An alternative method for smear preparation of fine-needle aspiration cytology of cystic thyroid lesions: Evaluation of sample adequacy.

Cystic thyroid lesions represent one of the most common causes of unsatisfactory fine-needle aspiration sampling. Thus, it is important to access the maximum number of follicular cells from cystic fluid in order to reduce unsatisfactory rates. We compared the traditional method of smearing with an alternative one. For each thyroid nodule, two smears were collected. Each smear was prepared using a distinct approach: either using the traditional technique or the alternative. Clinical data were taken from cytopathological request forms. The cytological aspects of the smears (eg, adequacy and number of cells) were observed during microscopy analysis. No cases were found to be suspicious for malignancy during ultrasound analysis (categories TR1 or TR2 according to ACR TI-RADS). Thirty-five cases were analyzed. For smears prepared using both the traditional and the alternative techniques, 20 and 4 cases, respectively, were unsatisfactory. In the 20 unsatisfactory traditional smear cases, 9 (45%) showed enough cells for diagnosis in cytospin and/or cell block samples; the four unsatisfactory alternative method cases showed the same. There was a statistical difference between the two methods of collecting a smear concerning sample adequacy (P < .001), but there was no statistical difference regarding the cellularity (P = .842). In our data, the alternative method of using only one slide and the needle tip had higher rates of adequate sampling. Since it is cost effective and does not change the cytological analysis, this proposed alternative method can be useful in cases of cystic thyroid lesions.

Estrogen suppresses bcl2 expression through dnmt1 in Japanese eel ovarian follicle.

Japanese eels are commercially valuable species in Asian aquaculture. This study evaluated whether salmon pituitary extract (SPE) or 17β-estradiol (E2) treatment can induce cytotoxic activity in eel ovarian follicles. Follicular cells died after exposure SPE for 24-h culture in an in vitro culture. Moreover, the E2 treatment also significantly reduced follicular cell counts. These results reveal that the inhibition of follicular cell numbers by SPE may occur through SPE-induced steroidogenesis. Results of a quantitative PCR analysis indicated that adding E2 to the culture decreased bcl2 and increased dnmt1 mRNA expression in Japanese eel follicular cells after 24 h. The results of a promoter assay revealed that E2 significantly increase dnmt1 promoter activity through estrogen receptor-binding site. An in silico analysis predicted several putative transcription factors targeting the bcl2 gene promoter region. Methylation of the bcl2 promoter accounted for the downregulation of bcl2 by E2-mediated dnmt1. The DNA methylation level of the bcl2 gene was significantly higher in E2-treated follicular cells than that in the control group. Finally, the E2-induced hypermethylation pattern of the bcl2 promoter and the reduction in follicular cell numbers were suppressed by adding an MTase inhibitor. Our findings demonstrate that estrogen has a negative effect on the reproductive system of female eels by regulating an epigenetic mechanism during artificial maturation.

Intraovarian injection of miR-224 as a marker of polycystic ovarian syndrome declines oocyte competency and embryo development.

miR-224 is associated with polycystic ovary syndrome (PCOS) that is an epidemic in reproductive age women. Most studies of miR-224 have focused on in vitro analyses, whereas the in vivo effects are not widely understood. In this study, we have conducted in silico analysis and found two potential miR-224 target genes, Ptx3 and Smad4 that have roles in folliculogenesis. Because patients with PCOS have decreased numbers of follicular cells related to cell apoptosis, we also investigated two apoptotic genes, Bax and Bcl2. We used the intraovarian injection method to deliver miR-224 into a mouse model. Histological examination of the ovaries was done by fluorescent microscope. Fertilization, cleavage, and developmental competence rates were counted under a stereomicroscope and compared between the studied groups. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis of miR-224 was conducted to determine the levels of the studied genes in the oocytes, cumulus cells, and blastocysts. The numbers of oocytes and fertilization rate indicated a higher apoptosis index ( p < 0.05) and increased numbers of degenerated embryos with irregular blastomeres and fragmented cytoplasm in the experimental group. RT-PCR results indicated a significant increase in miR-224 levels in the manipulated group. Of the four analyzed genes, Ptx3, Smad4, and Bcl2 had decreased levels in the transfected group, with increased Bax expression ( p < 0.05). This data showed that miR-224 negatively affected ovulation in the mouse model by decreasing Ptx3 and Smad4 expressions. The changes in Bcl2 and Bax expression levels, as apoptosis biomarkers, showed that apoptosis was a secondary outcome of the effect of miR-224.

The role of glucocorticoids in ovarian development of sleep deprived rats

ObjectiveSleep deprivation (SD) adversely affects female reproductive function. In this study, we investigated the role of glucocorticoids in ovarian development in sleep deprived rats. Materials and methodsFemale rats were subjected to SD for 1–4 days. Concentrations of serum estradiol and corticosterone were assessed. Betamethasone (BET) and/or recombinant human follicle-stimulating hormone (FSH) were administered to 21-day-old female rats for 2 days to evaluate ovarian status for follicular development. Intact preantral follicles were mechanically dissected from the rat's ovaries and cultured for 72 h with or without FSH in the presence or absence of BET to evaluate follicular development. ResultsSD led to a significant difference in serum estradiol concentrations between the sham and SD groups, and corticosterone concentrations were significantly elevated in groups with more than 2 days of SD (P < 0.05). FSH stimulated ovarian growth in immature rats, whereas BET inhibited ovarian development caused by the FSH treatment. Treatment of the preantral follicles with FSH induced an increase in both follicle size and follicular cell number, while follicular cell differentiation was accompanied by enhanced inhibin-α and connexin 43 expression. Inhibition of FSH-stimulated follicular growth through BET treatment exhibited a dose-dependent reciprocal trend; as the BET dose increased (0.001–1 μg/mL), preantral follicular growth decreased. This decrease was associated with a decrease in follicular cell numbers and suppression of a proliferating cell nuclear antigen, inhibin-α, and connexin 43 expression. ConclusionThe findings suggest that the adverse effects of SD may inhibit follicular development during ovarian hyperstimulation by corticosterone elevation in rat.

On the question of classification of rat’s ovarian follicles.

Background. Ovaries, as part of the female reproductive system, play an important role in the normal and adequate functioning of the body. The reproductive systemare sensitive to the effects of environmental factors.Among frequent causes of defection in ovarian structure and functions are factors of different backgrounds, and above all - the effect of these factors on the formation of the reproductive system during pregnancy.After all, the fetal period is one of the critical periods of the morphosis.During the pregnancy period female sex hormones are widely used, in particular, progesterone - a hormone of the corpus luteum, which performs a number of important functions and is essential for the normal pregnancy course.So the consequences of intrauterine affection of progesterone on morphogenesis and fetal ovarian functioninghave not been sufficiently studied. One of the methods for the morphofunctional status of the ovaries assessment is to calculate and to determine the ratio of follicles at different stages of development.Most part of the publications considering the study of the structure of the follicles and their distribution occurred at the end of the twentieth century. As the basis of proposed classifications of follicles different parameters were taken - diameter of the follicle, the ratio of the diameter of the follicle to the number of follicular cells, the structure of the follicle.Objective. To determine the most convenient classification of rat ovarian follicles. Methods. Literature data was analyzed,including the International Histological nomenclature. Results. The classifications were characterizedand the conclusions were drawn about their practical significancefor studying the processes of folliculogenesis, especially after the action of various factors.Conclusion. The investigationof morphofunctional featuresof follicles according to various criteria helps to assess in more detail the changes in their structure and functioning and to identify possible pathological changes after the. various factors impact, in particular – hormones.

Age-associated functional morphology of thyroid and its impact on the expression of vimentin, cytokeratins and VEGF. The role of nigella in refinement.

Aging causes morphological and functional changes in the thyroid gland. Free radicals play a key role in the pathology of normal aging. Vimentin and cytokeratin are cytoskeletal intermediate filaments that are often used as indirect indices of tissue injury. The aim of the study was to clarify the age-related alterations in the structure and function of the thyroid gland. The relationship between oxidative/antioxidative stress markers and cytoskeletal intermediate filaments (vimentin and cytokeratin) and oxidative/antioxidative stress markers as well as vascular endothelial growth factor (VEGF) during aging were elucidated. Finally, the role of Nigella sativa (NS) oil in ameliorating age-related alterations of the structure and function of the thyroid gland was studied. Thirty Sprague-Dawley albino rats were divided into five groups: young adult control, young adult NS-treated, late adult control, late adult NS-treated, and senile. The age of young adult, late adult, and senile rats was nearly 7, 18 and 22 months, respectively. NS oil was added to food pellets and was administered at a daily dose of 0.1 g/kg body weight for one month. The thyroid gland was dissected and fixed immediately in 10% formalin saline. The assessment of thyroid structure was based on hematoxylin and eosin, and Masson's trichrome stainings, and histomorphometric analysis of the deparaffinized sections. Localization and distribution of vimentin and cytokeratin filaments was assessed by immunohistochemistry. Measurements of VEGF gene expression by qPCR and oxidative/antioxidative markers (malondialdehyde and glutathione content, superoxide dismutase activity) in thyroid gland homogenates were performed. Serum concentration of thyroid hormones (T3, T4) and TSH were assessed by radioimmunoassay. Follicles in the late adult control group were dilated and disrupted. Follicular cells showed cytoplasmic vacuolation. Follicles in the thyroids of senile rats were of irregular shape, often with cellular exfoliations. Many follicles were dilated and lined with flattened cells. A notable amelioration of these morphological alterations was observed in late adult NS-treated rats. Decrease in serum T3 and T4 levels and increase in TSH levels were observed in the late adult control and senile groups. A clear shift of the oxidative/antioxidative markers (MDA/ /GSH, SOD) was observed in the late adult control and senile groups in favor of oxidants. Administration of NS to late adult rats resulted in normalization of these parameters. Increased area of collagen fibers, immunoreactivity of vimentin and cytokeratin filaments and VEGF gene expression were observed in the thyroids of late adult and senile rat groups as compared to young animals. The mean number of follicular cells decreased in the late adult control and senile groups. Administration of NS to the late adult rats returned these parameters to the level of the young adult rats. Aging-related alterations in both structure and function of the rat thyroid gland that are associated with increased indices of oxidative stress might be abrogated by administration of antioxidative agents present in Nigella sativa oil.

Effects of dietary vitamin E on reproductive performance and antioxidant capacity of Macrobrachium nipponense female shrimp

We evaluated the effects of dietary vitamin E on the reproductive performance and antioxidant capacity of Macrobrachium nipponense female shrimp. Prawns were fed 0, 40, 80, 160, 320 or 640 mg vitamin E/kg diet for 60 days. The 80 mg/kg group had the highest weight gain and lowest feed conversion rates. And the highest spawning rates were observed in the 80 mg/kg group with no significant differences among the groups. The highest activities of lysozyme, acid phosphatase and alkaline phosphatase in hepatopancreas were obtained in the 160 mg/kg group. The activities of superoxide dismutase, catalase and glutathione peroxidase showed a decreasing trend in the hepatopancreas. The lowest content of malondialdehyde was obtained with 80 and 160 mg/kg vitamin E. Histological results showed that the number of restzellen cells in hepatopancreas and a number of follicular cells in ovaries increased with 160 mg/kg vitamin E. However, 640 mg/kg vitamin E resulted in damaged hepatopancreas tubules and oocytes. The highest vitellogenin and vitellogenin receptor gene expressions were observed with 160 mg/kg vitamin E. These results provide evidence that dietary vitamin E with 80 and 160 mg/kg plays a positive impact on reproductive performance and antioxidant capacity of female shrimp.

Crosstalk of EGFR signalling with Notch and Hippo pathways to regulate cell specification, migration and proliferation in cockroach panoistic ovaries

Epidermal growth factor receptor (EGFR) signalling is crucial for the regulation of multiple developmental processes. Its function in relation to insect oogenesis has been thoroughly studied in the fly Drosophila melanogaster, which possesses ovaries of the highly modified meroistic type. Conversely, studies in other insect species with different ovary types are scarce. We have studied EGFR functions in the oogenesis of the cockroach Blattella germanica, a phylogenetically basal insect with panoistic ovaries. In this cockroach, depletion of EGFR expression aborts oocyte maturation and prevents oviposition, as affects the distribution of F-actins in the follicular cells of the basal ovarian follicle, which triggers premature apoptosis. In the younger ovarian follicles within the ovariole, depletion of EGFR expression reduces the number of follicular cells, possibly because the Hippo pathway is altered; moreover, the concomitant reduction of Notch expression results in the absence of stalk. Finally, depletion of EGFR determines an increase in the number of germinal cells. In the panoistic ovary of B. germanica, EGFR plays a role in the control of cell proliferation through interaction with Hippo and Notch pathways.

Morpho-functional characteristics of rat fetal thyroid gland are affected by prenatal dexamethasone exposure

Thyroid hormones (TH) and glucocorticoids strongly contribute to the maturation of fetal tissues in the preparation for extrauterine life. Influence of maternal dexamethasone (Dx) administration on thyroid glands morpho-functional characteristics of near term rat fetuses was investigated applying unbiased stereology. On the 16th day of pregnancy dams received 1.0mg/Dx/kg/b.w., followed by 0.5mg/Dx/kg/b.w. on the 17th and 18th days of gestation. The control females received the same volume of saline. The volume of fetal thyroid was estimated using Cavalieri’s principle; the physical/fractionator design was applied for the determination of absolute number of follicular cells in mitosis and immunohistochemically labeled C cells; C cell volume was measured using the planar rotator. The functional activity of thyroid tissue was provided from thyroglobulin (Tg) and thyroperoxidase (TPO) immunohistochemical staining. Applying these design-based modern stereological methods it was shown that Dx treatment of gravid females led to a significant decrease of fetal thyroid gland volume in 19- and 21-day-old fetuses, due to decreased proliferation of follicular cells. The Tg and TPO immunohistochemistry demonstrated that intensive TH production starts and continues during the examined period in control and Dx-exposed fetuses. Under the influence of Dx the absolute number of C cells was lower in both groups of near term fetuses, although unchanged relation between the two populations of endocrine cells, follicular and C cells suggesting that structural relationships within the gland are preserved. In conclusion maternal glucocorticoid administration at the thyroid gland level exerts growth-inhibitory and maturational promoting effects in near term rat fetuses.

Ultrasound-Guided Fine-Needle Aspiration Biopsy of Clinically Suspicious Thyroid Nodules with an Automatic Aspirator: A Novel Technique

Fine-needle aspiration biopsy (FNAB) is a simple technique for the investigation of suspicious thyroid nodules. However, low success rates are reported in the literature. The aim of this prospective study was to compare the clinical performance and impact of an automatic aspirator, referred to here as Aspirator 3, to those of the manual technique for the FNAB of clinically suspicious thyroid nodules. One hundred nine consecutive patients with 121 clinically suspicious thyroid nodules underwent a biopsy twice of the same site with the clinically approved Aspirator 3 and with the manual technique. The number of follicular cell formations and the total number of follicular cells in the aspirate were counted using the ThinPrep® method. With the Aspirator 3, the total number and the mean number of extracted cell formations were significantly higher than the values achieved with the manual technique (total: 3222 vs. 1951, p=0.02; mean: 27 vs. 16). The total number of cells that were biopsied was also higher when the Aspirator 3 was utilized (47,480 vs. 23,080, p=0.005). Overall, the Aspirator 3 was superior in 65 biopsies, and the manual technique was superior in 39 biopsies. In terms of cell formations and the total number of cells aspirated, the Aspirator 3 was superior to the manual technique. Further, the Aspirator 3 was more convenient to use and had a greater precision in needle guidance.

Quantification, Morphology and Ultrastructure of Preantral Follicles of Buffalo (Bubalus bubalis) Foetuses

The objective of this study was to determine the number, morphology and ultrastructure of preantral ovarian follicles of buffalo (Bubalus bubalis) foetuses at different ages. Quantification revealed number of primordial, primary and secondary follicles of 48,857 ± 17,506, 26,000 ± 20,452, 18,428 ± 10,875 and 18,375 ± 19,690, 225 ± 349, 326 ± 288 at 12-34 cm and 35-60 cm crown rump length (CRL), respectively. Follicular diameter values were 28.9 (± 3.4), 34.7 (± 5.9) and 59.4 (± 12.6) μm; oocyte diameters were 21.7 (± 2.8), 24.3 (± 3.4) and 33.0 (± 7.7) μm, and the numbers of follicular cells in the follicle equatorial section were 7.1 (± 1.4), 12.0 (± 2.4) and 13.8 (± 2.4) for primordial, primary and secondary follicles, respectively. The primordial follicle consisted of an oocyte surrounded by a layer of flattened follicular cells with a normally eccentric oocyte nucleus. Dispersed Golgi complex, smooth endoplasmic reticulum, rounded mitochondria and several lipid vesicles were observed in the cytoplasm and cell junctions between the follicle cell membranes and the oocyte. This work describes the number, morphometry and ultrastructure of preantral follicles of buffalo foetuses, concluding that folliculogenesis is established between 8 and 34 cm CRL and that follicle number varies individually and according to age and that further studies are needed in this species.

Pathologic features of polycystic thyroid disease: Comparison with benign nodular goiter

Polycystic thyroid disease (PCTD) is characterized by multiple thyroid cysts detected by ultrasonography, the absence of thyroid autoantibodies, and susceptibility to the development of hypothyroidism due to a high iodine intake. It is necessary to obtain histopathological information on PCTD in order to clarify the cause of hypothyroidism. We retrospectively reviewed three patients with PCTD and small papillary thyroid cancer who underwent thyroidectomy. We observed the thyroid tissues pathologically in areas with and without multiple cysts, and compared them with those of multinodular goiter with cysts. In the patients with PCTD, there were multiple enlarged follicles that resembled enlarged normal follicles and differed from those found in multinodular goiter in terms of their shape. Huge follicles corresponded to the cysts that were detected by ultrasonography. Each follicle contained colloid. Follicular cells in enlarged follicles comprised low cuboidal epithelium that appeared normal. These findings were common in the 3 patients with PCTD. In Conclusion the PCTD patients had multiple enlarged follicles that seemed to decrease the total number of follicular cells, and may be a cause of hypothyroidism. We believe that PCTD is a new entity of thyroid disease based on the pathological findings.

Follicular apoptosis in the mussel (Mytella strigata) as potential indicator of environmental stress in coastal ecosystems

Follicular apoptosis in the tropical mussel Mytella strigata was assessed in three coastal lagoons located in the southern Gulf of California, Mexico. Mussels were collected from three coastal lagoons associated with different scenarios of anthropogenic stress during one year. The gonad of each mussel was dissected, weighed, and sampled for histology and apoptosis analysis by TUNEL labeling. Two apoptotic indices were used: the apoptotic index of cells (AIC) based on the number of follicular cells in apoptosis in one thousand cells counted per gonad, and the apoptotic index of follicles (AIF) based on the number of follicular cells per follicle per gonad. Both indices showed high association with each other for all developmental stages, although AIF seemed to better discriminate among sites. Higher AIF and AIC were observed at the Urias Estuary (1.6 and 1.5 respectively) ranked as highly polluted, followed by Ensenada del Pabellon (0.82 and 0.95 respectively), ranked as moderately polluted, and the Teacapan Estuary (0.57 and 0.76 respectively) ranked as slightly polluted. Our data indicate that the apoptotic index in tropical mussels could be a useful indicator of environmental stress in coastal ecosystems; however, the ecological relevance of follicular apoptosis in polluted environments needs further investigation.

Absence of microfollicular basement membrane: A new indicator in the diagnosis of follicular carcinoma thyroid

The thyroid follicles represent a biological continuum. Each follicle is closely related to the follicle that is next to it. The important feature of a follicular carcinoma is a microfollicular pattern. We report a case of follicular carcinoma in a 48-year-old female that demonstrates microfollicles which are larger in size and contain more number of follicular cells in cytologic smears (20-29 cells) in contrary to the literature definition of microfollicles containing approximately 6-12 cells. We also demonstrate absence of basement membranes in these microfollicles in histologic sections by Silver Methanamine Stain, which may be an indicator to search for vascular and capsular invasion. This case report also describes postoperative positron emission tomography scan findings.

Thyroid-Specific Enhancer-Binding Protein/NKX2.1 Is Required for the Maintenance of Ordered Architecture and Function of the Differentiated Thyroid

Thyroid-specific enhancer-binding protein (T/ebp)/Nkx2.1-null mouse thyroids degenerate by embryonic day (E) 12-13 through apoptosis whereas T/ebp/Nkx2.1-heterogyzgous mice exhibit hypothyroidism with elevated TSH levels. To understand the role of T/ebp/Nkx2.1 in the adult thyroid, a thyroid follicular cell-specific conditional knockout (KO) mouse line, T/ebp(fl/fl);TPO-Cre, was established that expresses Cre recombinase under the human thyroid peroxidase (TPO) gene promoter. These mice appeared to be healthy and exhibited loss of T/ebp/Nkx2.1 expression in many, but not all, thyroid follicular cells as determined by immunohistochemistry and real-time PCR, thus presenting a T/ebp-thyroid-conditional hypomorphic mice. Detailed analysis of the thyroids from T/ebp(fl/fl), T/ebp(fl/fl);TPO-Cre, and T/ebp(fl/ko) mice, where the latter mouse line is derived from crosses with the original T/ebp/Nkx2.1-heterozygous mice, revealed that T/ebp(fl/fl);TPO-Cre mice can be classified into two groups with different phenotypes: one having atrophic/degenerative thyroid follicles with frequent presence of adenomas and extremely high serum TSH levels, and the other having an altered thyroid structure with reduced numbers of extraordinary dilated follicles consisting of excessive numbers of follicular cells as compared with those usually found in the normal thyroid. The latter phenotype was also observed in aged T/ebp(fl/ko) mouse thyroids. In vitro three-dimensional thyroid primary cultures using thyroids from T/ebp(fl/fl);TPO-Cre, T/ebp(fl/ko), and T/ebp(fl/fl) mice, and the latter treated with recombinant adenovirus with and without Cre expression, demonstrated that only cells from T/ebp(fl/fl) mice without adeno-Cre treatment formed follicular structures. Taken together, these results suggest that T/ebp/Nkx2.1 is required for maintenance of the normal architecture and function of differentiated thyroids.

Effect of various growth factors on the in vitro development of goat preantral follicles

The effect of transforming growth factor-α (TGF-α; 10 ng ml −1), insulin-like growth factor-II (IGF-II; 20 ng ml −1), epidermal growth factor (EGF; 50 ng ml −1) and FSH (1 μg ml −1) was investigated in the in vitro development of goat preantral follicles (PFs). The control medium was bicarbonate buffered Tissue Culture Medium 199 (TCM 199B), without supplementation. Small (40–60 μm) and large (61–100 μm) PFs were cultured for 6 days. In vitro growth of the PFs was assessed by the increase in follicle diameter, oocyte diameter, DNA synthesis by follicular cells and follicular cell number. All growth factors studied induced DNA synthesis in the small and large goat PFs. A significant increase in diameter of the follicles (EGF: 51.18 ± 0.71 versus 58.19 ± 1.41 and FSH: 53.14 ± 0.71 versus 58.30 ± 1.30) and follicular cell number (EGF: 39.21 ± 1.20 versus 55.96 ± 1.32 and FSH: 40.34 ± 1.25 versus 51.75 ± 1.81) was observed in small PFs cultured in EGF and FSH supplemented media. In the large PFs, only EGF induced a significant increase in follicle diameter and follicular cell number. It was concluded that EGF is mitogenic to goat PFs, FSH is capable of inducing growth in small but not large PFs and TGF-α and IGF-II are stimulatory to goat PFs in culture.

Epithelium–mesenchyme compartment interaction and oncosis on chemotherapy-induced hair damage

It is known that chemotherapy induces alopecia in humans, with important psychological and social implications in spite of its reversibility. Among chemotherapeutic drugs, anthracyclines are widely used, yet cause severe alopecia. One of the causes for the elevated sensibility of hair follicles to anthracyclines, and to drugs in general, is the high proliferation rate of follicular epithelium and the long duration of the growth phase (up to 7 years in humans). To clarify the mechanism of anthracycline toxicity, we used a rat model and focused our attention on the morphological alterations in hair follicles induced by doxorubicin. We observed the progression of hair follicle degeneration in the epithelial and mesenchymal compartments until alopecia arose, by both light and electron microscopy. As a first sign of damage, significant apoptosis was detected in the proximal perifollicular connective tissue sheath and sporadically in the matrix, near the interface between matrix and follicular papilla. We propose the apoptotic remodeling of the mesenchymal compartment as a process that is fundamental to the progression of events leading to alopecia. Regarding the epithelial compartment, it is important to note that oncosis was observed in a large number of follicular cells in the outer root sheath during the last stages of hair follicle regression. This indicates that oncosis is involved in a major way in the damage of epithelial cells.

Influence of transforming growth factor-α, insulin-like growth factor-II, epidermal growth factor or follicle stimulating hormone on in vitro development of preantral follicles in sheep

In an attempt to identify factor(s) that influence in vitro development of preantral follicles (PFs) in sheep, small (40–60 μm in diameter) and large (61–100 μm in diameter) PFs were cultured for 6 days in tissue culture medium (TCM 199) supplemented with transforming growth factor-α (TGF-α), insulin-like growth factor-II (IGF-II), epidermal growth factor (EGF) or follicle stimulating hormone (FSH). Increase in follicle diameter, oocyte diameter, induction of new DNA synthesis in the follicular cells and increase in number of follicular cells per follicle were measured as the indicators of development. Only EGF supplemented medium increased the follicle diameter, number of follicular cells and also induced intense DNA synthesis in both small and large PFs. TGF-α, IGF-II and FSH on the other hand were able to stimulate intense DNA synthesis only in large PFs. None of the supplemented media caused an increase in oocyte diameter. It is proposed that EGF stimulates the development of preantral follicles of sheep up to 100 μm in diameter.