Limits...
Effects of chronic estradiol treatment on the thyroid gland structure and function of ovariectomized rats.

Abdel-Dayem MM, Elgendy MS - BMC Res Notes (2009)

Bottom Line: The results of this study revealed that serum levels of T3 and T4 decreased in ovariectomized animals and significantly increased after estradiol treatment, while TSH increased in ovariectomized animals and decreased with estradiol treatment.After estradiol treatment the follicles became smaller in size, having small amount of colloid with increased epithelial height in addition to decreased connective tissue content.Ultrastructural study supported these results in addition to the presence of large amount of intracytoplasmic colloid vesicles after estradiol treatment.

View Article: PubMed Central - HTML - PubMed

Affiliation: Histology Department, Faculty of Medicine, Fayoum University, Fayoum, Egypt. dmenna@msn.com

ABSTRACT

Background: Estrogen therapy is widely used nowadays in women to treat many postmenopausal symptoms but it may have some undesirable effects due to multiple organs affection. So, the aim of this study was to determine the effects of chronic estradiol treatment on the structure and function of the thyroid gland in ovarictomized rats as a model simulating menopause.

Findings: Thirty adult female Wistar rats divided into three groups were used in this study; the first group was sham-operated, while the second and third groups were ovariectomized. The first and second groups were injected with olive oil while the third group was injected with estradiol dipropionate daily for three months, after that; hormonal assay for T3, T4, TSH and specimens of the thyroid were taken and processed to be examined by light and electron microscopy. The results of this study revealed that serum levels of T3 and T4 decreased in ovariectomized animals and significantly increased after estradiol treatment, while TSH increased in ovariectomized animals and decreased with estradiol treatment. Histological and morphometric study in ovariectomized group revealed marked accumulation of colloid in follicular lumens with decreased epithelial height in addition to increased connective tissue amount. After estradiol treatment the follicles became smaller in size, having small amount of colloid with increased epithelial height in addition to decreased connective tissue content. Ultrastructural study supported these results in addition to the presence of large amount of intracytoplasmic colloid vesicles after estradiol treatment.

Conclusion: Low estrogen level may lead to mild thyroidal hypofunction while estradiol treatment may lead to hyperactivity so it should be used very cautiously in the treatment of postmenopausal symptoms to avoid its undesirable stimulatory effect on the thyroid.

No MeSH data available.


Related in: MedlinePlus

electron micrograph of thyroid follicular cells in (a) sham operated rats, (b) ovariectomized rats and (c) ovariectomized rats treated with estradiol. (a) This is a part of a thyroid follicle. The follicles are bounded with a basement membrane (double arrows) and surrounded with capillaries (Cap). Two follicular cells with rounded nuclei (N) and a parafollicullar cell (P) could be demonstrated. In the follicular cells; saccules of Golgi apparatus (curved arrow), prominent endoplasmic reticular cisternae (thick arrows), rounded mitochondria (arrow heads), lysosomes (dashed arrows) intracytoplasmic colloid vesicles (thin arrows) with mild apical vacuolization near the center of the follicle (C) could be demonstrated (EM × 2000). (b) There are rounded nuclei of follicular cells (N), while the mitochondria (arrow heads) and endoplasmic reticular cisternae (thick arrows) showed no remarkable changes. Intracytoplasmic colloid vesicles (thin arrows) were more prominent while the apex of the cell facing colloid (C) showed microvilli (double arrows) and many lysosomes (dashed arrows) with apical vacuolization could be clearly demonstrated (EM × 2000). (c) There are oval nuclei (N), endoplasmic reticular cisternae (thick arrows) and prominent rounded mitochondria (arrow heads) were comparable to the control group. Large amount of intracytoplasmic colloid vesicles (thin arrows) were much more evident, while the apex of the cell facing colloid (C) showed microvilli (double arrows) with much more apical vacuolization and many lysosomes (dashed arrows) (EM × 2000).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2743701&req=5

Figure 4: electron micrograph of thyroid follicular cells in (a) sham operated rats, (b) ovariectomized rats and (c) ovariectomized rats treated with estradiol. (a) This is a part of a thyroid follicle. The follicles are bounded with a basement membrane (double arrows) and surrounded with capillaries (Cap). Two follicular cells with rounded nuclei (N) and a parafollicullar cell (P) could be demonstrated. In the follicular cells; saccules of Golgi apparatus (curved arrow), prominent endoplasmic reticular cisternae (thick arrows), rounded mitochondria (arrow heads), lysosomes (dashed arrows) intracytoplasmic colloid vesicles (thin arrows) with mild apical vacuolization near the center of the follicle (C) could be demonstrated (EM × 2000). (b) There are rounded nuclei of follicular cells (N), while the mitochondria (arrow heads) and endoplasmic reticular cisternae (thick arrows) showed no remarkable changes. Intracytoplasmic colloid vesicles (thin arrows) were more prominent while the apex of the cell facing colloid (C) showed microvilli (double arrows) and many lysosomes (dashed arrows) with apical vacuolization could be clearly demonstrated (EM × 2000). (c) There are oval nuclei (N), endoplasmic reticular cisternae (thick arrows) and prominent rounded mitochondria (arrow heads) were comparable to the control group. Large amount of intracytoplasmic colloid vesicles (thin arrows) were much more evident, while the apex of the cell facing colloid (C) showed microvilli (double arrows) with much more apical vacuolization and many lysosomes (dashed arrows) (EM × 2000).

Mentions: Electron microscopic study of the thyroid follicles in control sham operated rats showed rounded follicles formed of cuboidal cells with rounded nuclei. The follicles are bounded with a basement membrane and surrounded with capillaries. The cells are rich in rough endoplasmic reticulum and mitochondria in addition to a prominent Golgi apparatus and intracytoplasmic colloid vesicles. The apex of the cells adjacent to the follicular lumen showed apical cytoplasmic vacuolization with the presence of many lysosomes (fig. 4a).


Effects of chronic estradiol treatment on the thyroid gland structure and function of ovariectomized rats.

Abdel-Dayem MM, Elgendy MS - BMC Res Notes (2009)

electron micrograph of thyroid follicular cells in (a) sham operated rats, (b) ovariectomized rats and (c) ovariectomized rats treated with estradiol. (a) This is a part of a thyroid follicle. The follicles are bounded with a basement membrane (double arrows) and surrounded with capillaries (Cap). Two follicular cells with rounded nuclei (N) and a parafollicullar cell (P) could be demonstrated. In the follicular cells; saccules of Golgi apparatus (curved arrow), prominent endoplasmic reticular cisternae (thick arrows), rounded mitochondria (arrow heads), lysosomes (dashed arrows) intracytoplasmic colloid vesicles (thin arrows) with mild apical vacuolization near the center of the follicle (C) could be demonstrated (EM × 2000). (b) There are rounded nuclei of follicular cells (N), while the mitochondria (arrow heads) and endoplasmic reticular cisternae (thick arrows) showed no remarkable changes. Intracytoplasmic colloid vesicles (thin arrows) were more prominent while the apex of the cell facing colloid (C) showed microvilli (double arrows) and many lysosomes (dashed arrows) with apical vacuolization could be clearly demonstrated (EM × 2000). (c) There are oval nuclei (N), endoplasmic reticular cisternae (thick arrows) and prominent rounded mitochondria (arrow heads) were comparable to the control group. Large amount of intracytoplasmic colloid vesicles (thin arrows) were much more evident, while the apex of the cell facing colloid (C) showed microvilli (double arrows) with much more apical vacuolization and many lysosomes (dashed arrows) (EM × 2000).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2743701&req=5

Figure 4: electron micrograph of thyroid follicular cells in (a) sham operated rats, (b) ovariectomized rats and (c) ovariectomized rats treated with estradiol. (a) This is a part of a thyroid follicle. The follicles are bounded with a basement membrane (double arrows) and surrounded with capillaries (Cap). Two follicular cells with rounded nuclei (N) and a parafollicullar cell (P) could be demonstrated. In the follicular cells; saccules of Golgi apparatus (curved arrow), prominent endoplasmic reticular cisternae (thick arrows), rounded mitochondria (arrow heads), lysosomes (dashed arrows) intracytoplasmic colloid vesicles (thin arrows) with mild apical vacuolization near the center of the follicle (C) could be demonstrated (EM × 2000). (b) There are rounded nuclei of follicular cells (N), while the mitochondria (arrow heads) and endoplasmic reticular cisternae (thick arrows) showed no remarkable changes. Intracytoplasmic colloid vesicles (thin arrows) were more prominent while the apex of the cell facing colloid (C) showed microvilli (double arrows) and many lysosomes (dashed arrows) with apical vacuolization could be clearly demonstrated (EM × 2000). (c) There are oval nuclei (N), endoplasmic reticular cisternae (thick arrows) and prominent rounded mitochondria (arrow heads) were comparable to the control group. Large amount of intracytoplasmic colloid vesicles (thin arrows) were much more evident, while the apex of the cell facing colloid (C) showed microvilli (double arrows) with much more apical vacuolization and many lysosomes (dashed arrows) (EM × 2000).
Mentions: Electron microscopic study of the thyroid follicles in control sham operated rats showed rounded follicles formed of cuboidal cells with rounded nuclei. The follicles are bounded with a basement membrane and surrounded with capillaries. The cells are rich in rough endoplasmic reticulum and mitochondria in addition to a prominent Golgi apparatus and intracytoplasmic colloid vesicles. The apex of the cells adjacent to the follicular lumen showed apical cytoplasmic vacuolization with the presence of many lysosomes (fig. 4a).

Bottom Line: The results of this study revealed that serum levels of T3 and T4 decreased in ovariectomized animals and significantly increased after estradiol treatment, while TSH increased in ovariectomized animals and decreased with estradiol treatment.After estradiol treatment the follicles became smaller in size, having small amount of colloid with increased epithelial height in addition to decreased connective tissue content.Ultrastructural study supported these results in addition to the presence of large amount of intracytoplasmic colloid vesicles after estradiol treatment.

View Article: PubMed Central - HTML - PubMed

Affiliation: Histology Department, Faculty of Medicine, Fayoum University, Fayoum, Egypt. dmenna@msn.com

ABSTRACT

Background: Estrogen therapy is widely used nowadays in women to treat many postmenopausal symptoms but it may have some undesirable effects due to multiple organs affection. So, the aim of this study was to determine the effects of chronic estradiol treatment on the structure and function of the thyroid gland in ovarictomized rats as a model simulating menopause.

Findings: Thirty adult female Wistar rats divided into three groups were used in this study; the first group was sham-operated, while the second and third groups were ovariectomized. The first and second groups were injected with olive oil while the third group was injected with estradiol dipropionate daily for three months, after that; hormonal assay for T3, T4, TSH and specimens of the thyroid were taken and processed to be examined by light and electron microscopy. The results of this study revealed that serum levels of T3 and T4 decreased in ovariectomized animals and significantly increased after estradiol treatment, while TSH increased in ovariectomized animals and decreased with estradiol treatment. Histological and morphometric study in ovariectomized group revealed marked accumulation of colloid in follicular lumens with decreased epithelial height in addition to increased connective tissue amount. After estradiol treatment the follicles became smaller in size, having small amount of colloid with increased epithelial height in addition to decreased connective tissue content. Ultrastructural study supported these results in addition to the presence of large amount of intracytoplasmic colloid vesicles after estradiol treatment.

Conclusion: Low estrogen level may lead to mild thyroidal hypofunction while estradiol treatment may lead to hyperactivity so it should be used very cautiously in the treatment of postmenopausal symptoms to avoid its undesirable stimulatory effect on the thyroid.

No MeSH data available.


Related in: MedlinePlus