Ovaries may take on job in immune system after their tenure as reproductive organs (Jun 2026, mice) The post-reproductive ovary shifts from a reproductive to an immune-like organ Study

[Michael Harrop]

https://medicalxpress.com/news/2026-07-ovaries-job-immune-tenure-reproductive.html
https://academic.oup.com/molehr/article/32/2/gaag038/8705536

For most women, the body begins to change dramatically in their 40s or 50s. This transition, known as menopause, is defined as 12 consecutive months without a menstrual period, marking the end of the reproductive years. While researchers are aware of the functions the ovaries perform during active reproductive years, what happens to the organ after menopause is largely a mystery.

Researchers found that even after the ovary can no longer support reproduction, it doesn't simply become inactive. Instead, aging ovaries undergo remarkable changes, producing a different set of signaling molecules from those of younger ovaries.

In doing so, the ovary shifts away from its reproductive role and transforms into an organ that assumes immune functions, participating in processes such as inflammatory signaling and leukocyte activation.

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Abstract​

Reproductive aging in females is characterized by the irreversible depletion of ovarian follicles, yet the structure and function of the post-reproductive ovary remain poorly defined.

Using paired histological and bulk transcriptomic analyses of ovaries from reproductively young (2 m), reproductively old (18 m), and post-reproductive (24 m) mice, we mapped how ovarian identity evolves beyond follicle exhaustion. As expected, follicle loss, stromal remodeling, and increased collagen deposition were observed in the reproductively old and post-reproductive cohorts. Transcriptomic analyses revealed a shift from reproductive functionality to an immune-dominant signature with age. Correspondingly, post-reproductive ovaries exhibited increased infiltration of T cells, macrophages, and multinucleated giant cells.

Although old and post-reproductive ovaries diverged substantially from young ovaries, they also showed discrete transcriptomic differences, indicating that the ovary continues to undergo molecular changes after reproductive senescence. Lastly, age-dependent changes in ovarian factors that are predicted to be secreted suggest that the post-reproductive ovary could be a source of pro-inflammatory signaling mediators with the potential to modulate extra-ovarian tissues.

These findings challenge the assumption that the post-reproductive ovary is inert, instead indicating that it acquires an immune identity with potential endocrine and paracrine influence on whole-body aging.

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