Characteristics of uterine aging

Abstract

Uterine aging is in part responsible for a decline in fecundity which begins in middle age in most mammals. Characteristics of uteri from a variety of animals in middle age and old age are reviewed and the factors which may be responsible for this decline discussed. These include age-related changes in the hypothalamus, pituitary, and ovaries; loss of number or function of steroid hormone receptors; morphological changes in the uterine epithelium; the accumulation of collagen fibrils in the uterine stroma; and loss or impairment of the decidual response. The ultrastructural morphology of uterine epithelial, stromal, and decidual tissue from 4 month old and 18 month old Fischer 344 rats is presented and compared.

Determinants of uterine aging: lessons from rodent models

“…The density of collagen fibrils increased with age, especially in the basal areas of the endometrium, where the degree of cellularity was markedly diminished and collagen bundles formed large, closely packed aggregates. The majority of fibrils measured was between 35 and 60 nm in diameter, and loosely arranged in the subluminal areas and more aggregated deeper into the tissue [16].…”

“…Golgi cisternae were sometimes dilated in older animals but were in general similar to those seen in young rats. Secondary lysosomes, with contents of variable electron density, were often increased in the older animals [16]. The stroma cells, which need to be differentiated to decidual cells, also had different appearances between the young and old animals.…”

“…The most notable change in the aging uterus was a dramatic increase in uterine collagen [16,53,54]. This collagen deposition in aging mice was stimulated by estrogen [55].…”

“…Remodeling of the extracellular matrix during decidualization appeared to be a requirement and function of decidual cells in human and rodent uteri [76]. The abnormally deposited extracellular matrix, such as collagen, appeared to prevent the formation of extensive junctional complexes and interdigitation, which may impair the stromal-decidual transformation and subsequent placental development [16].…”

“…The endometrial environment of uteri is proved to be one of the critical aspects to determine the reproductive capacity [14] and uterine factor has been proved to be critical for the decline of fecundity in both rodents and humans [4,15]. Most of the available information on uterine aging derives from studies on rats and mice [16]. In these species, life span is short and aging animal model can be easily established.…”