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Updated: Aug 21, 2026
Depletion and Reconstitution of Macrophages in Mice
Published on: August 1, 2012
Ultrastructure of testicular macrophages in aging mice
Francesco Giannessi1, Maria A Giambelluca, Maria C Scavuzzo
1Dipartimento di Morfologia Umana e Biologia Applicata Facoltà di Medicina e Chirurgia, Università di Pisa, Pisa, Italy.
Abstract:
Testicular macrophages of aging mice were studied by TEM. Testicular macrophages retained with Leydig cells the close morphological relationships observed in the adult young animals, but digitations were not found. Lipofuscin granules like those of the Leydig cells from aging mice were observed in the cytoplasm. These organelles were generally absent in the testicular macrophages of young adult mice. Testicular macrophages did not display phagocytosis of the lipofuscin granules. In addition, the latter were not found in the intercellular spaces. These observations indicated that lipofuscin granules were formed, at least in a great part, within testicular macrophages as a consequence of metabolic changes occurring with age. Fine lamellar organization was seen in the lipofuscin granules of both Leydig cells and testicular macrophages. Frequently, lipofuscin granules originated from secondary lysosomes containing lipidic vacuoles only. Together with accumulation of the lipofuscin granules, changes of testicular macrophage fine morphology were observed. Endoplasmic reticulum and Golgi apparatus became poorly developed, and coated vesicles were rarely found. Fewer mitochondria were encountered, but their ultrastructure was not altered. These results suggest that in testicular macrophages lipofuscin accumulation is associated with a functional involution.
Insights
Aging testicular macrophages accumulate lipofuscin granules, indicating a decline in cellular function. These granules appear to form within the macrophages, suggesting age-related metabolic changes impact testicular health.
Area of Science:
- Reproductive biology
- Cellular aging
- Immunology
Background:
- Testicular macrophages play a crucial role in maintaining testicular function.
- Aging is associated with cellular changes in various tissues, including the testes.
- The specific changes in testicular macrophages during aging are not fully understood.
Purpose of the Study:
- To investigate the morphological and functional changes in testicular macrophages of aging mice.
- To determine the origin and characteristics of lipofuscin granules in aging testicular macrophages.
Main Methods:
- Transmission electron microscopy (TEM) was used to examine testicular macrophages from young adult and aging mice.
- Morphological relationships between macrophages and Leydig cells were analyzed.
- The presence, origin, and ultrastructure of lipofuscin granules were studied.
Main Results:
- Testicular macrophages in aging mice exhibited close morphological relationships with Leydig cells, but lacked digitations.
- Lipofuscin granules, similar to those in Leydig cells, were observed in the cytoplasm of aging testicular macrophages but were absent in young mice.
- These granules appeared to originate from secondary lysosomes and were not phagocytosed by macrophages, suggesting intracellular formation due to metabolic changes.
Conclusions:
- Lipofuscin accumulation in testicular macrophages of aging mice is likely a result of age-related metabolic alterations.
- The presence of lipofuscin correlates with a decline in testicular macrophage morphology, including poorly developed endoplasmic reticulum and Golgi apparatus.
- These findings suggest that lipofuscin accumulation is associated with functional involution of testicular macrophages during aging.
