science
Mouse Ovaries Show Fewer Follicles, More Scarring, and Higher Immune-Cell Activity With Age
Northwestern University researchers examined ovaries from mice aged 2, 18 and 24 months. Older ovaries lost follicles, gained scarring and displayed more active inflammation-related genes along with higher counts of T cells and macrophages. A related March study on post-menopausal human ovaries remains unpublished.
Jul 9, 1:29 PM·1m read1 source
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Researchers at Northwestern University examined the ovaries of mice aged 2 months, 18 months and 24 months, analyzing tissue structure and gene expression in each group. Ovaries from the older mice showed fewer egg-producing follicles, more scarring, and reduced activity of genes tied to reproduction and estradiol production.
At the same time, genes linked to inflammation and immune activity increased, and the number of immune cells including T cells and macrophages rose with age.
The mouse study appears in the journal Molecular Human Reproduction with DOI 10.1093/molehr/gaag038. In March, the same team published findings on the protein composition of ovaries from post-menopausal women aged 50 to 75; that work has not yet been peer reviewed. Francesca Duncan at Northwestern University said the results were unexpected.
“We assumed the organ had done its job [post-reproduction],” she stated. ” Mice do not undergo menopause or shed a uterine lining but experience age-related loss of fertility and hormonal function as egg reserves decline. Duncan noted that the ovaries appeared to shift from a reproductive signature toward an immune signature.
Diana Laird at the University of California, San Francisco, said similar immune changes may occur in humans because both species stop cycling once oocyte supply falls below a threshold and share other age-related ovarian changes such as fibrosis.
