Morphological and Functional Changes in the Thyroid Follicles of the Aged Murine and Humans

Abstract

BackgroundAlthough both thyroid histology and serum concentrations of hormones are known to change with age, only a few reports exist on the relationship between the age-related structural and functional changes of the thyroid follicles in both mice and humans. Our objectives were to investigate age-related histological changes of the thyroid follicles and to determine whether these morphological changes were associated with the functional activity of the follicles.MethodsThe thyroid glands of mice at 18 weeks and at 6, 15, and 30 months of age were histologically examined, and the serum levels of thyroid hormones were measured in 11-week-old and 20-month-old mice. Samples of human thyroid tissue from 10 women over 70 years old and 10 women between 30 and 50 years of age were analyzed in conjunction with serum thyroid hormone level.ResultsThe histological and functional changes observed in the thyroid follicles of aged mice and women were as follows: variable sizing and enlargement of the follicles; increased irregularity of follicles; Sanderson’s polsters in the wall of large follicles; a large thyroglobulin (Tg) globule or numerous small fragmented Tg globules in follicular lumens; oncocytic change in follicular cells; and markedly dilated follicles empty of colloid. Serum T3 levels in 20-month-old mice and humans were unremarkable.ConclusionsThyroid follicles of aged mice and women show characteristic morphological changes, such as cystic atrophy, empty colloid, and Tg globules.

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

“…Follicles were dilated and disrupted in considerable portions of the gland. These findings are similar to those of other authors [30]. Follicular disruption observed in our study in the thyroids of aged rats may result in a follicular fusion, and, hence, the emergence of dilated large follicles.…”

“…These vacuolations reflect the endocytotic activity of thyrocytes during thyroid hormones' release [3]. In the thyroids of late adult control and senile rats, many follicles were devoid of the colloid which is a distinctive sign of inactive follicles [30].…”

Morphological and functional changes in neonatally X-irradiated thyroid gland in rats

“…In fact, there were no increases in thyroid weights in the Neo-X groups. In the thyroid gland, follicle size is not uniform and depends on the location in the gland: peripheral follicles are larger than central follicles [15,26]. Then we performed the histomorphological analysis both in the peripheral zone and the central zone separately.…”

“…The areas of epithelium were obtained subtracting colloid areas from follicular areas [14]. The 'peripheral zone' was defined as the area within 2 layers of follicles from the outer layer of the gland, otherwise it was defined as 'central zone' [15].…”

Sanderson's polster

“…opined that Sanderson's polsters, small follicles and irregularly-shaped follicles, were hyperactive as compared with markedly enlarged follicles. [ 5 ] Abundant colloid in large follicles was stained purple-red or dark blue-purple by PAS, while cellular areas composed of small follicles were pale-red or negative. In another study, Aeschimann et al .…”