Related Experiment Video
Updated: Aug 30, 2026
Depletion and Reconstitution of Macrophages in Mice
Published on: August 1, 2012
Macrophage populations in L-cysteine-induced rat sperm granulomas
O Sawamoto1, J Yamate, M Kuwamura
1Division of Pharmacology, Drug Safety and Metabolism, Otsuka Pharmaceutical Factory, Inc, 115 Tateiwa, Muya-cho, Naruto, Tokushima 772-8601, Japan.
Abstract:
Histopathologically, sperm granulomas consist of a central mass of degenerating spermatozoa surrounded by many epithelioid macrophages and lymphocytes. Using monoclonal antibodies (ED1, ED2, and OX6), the authors investigated immunohistochemically the participation of different macrophage populations in epididymal sperm granulomas induced in pubertal rats by repeated injection of L-cysteine. Monocyte-like and epithelioid macrophages expressed the ED1 antigen found on activated lysosomal membranes in rat blood monocytes and exudate macrophages, but did not express the ED2 antigen found on the membrane antigens of rat resident macrophages. Cells expressing MHC class II antigens (as detected by the OX6 antibody) were present in the granulomas in moderate numbers, particularly in the early stages. Ultrastructurally, fragmented spermatozoa were observed in the cytoplasm of epithelioid macrophages. These findings suggest that macrophages appearing in rat sperm granulomas originate mainly from blood monocytes, and that they have a high phagocytic activity and a potential for antigen presentation.
Insights
Macrophages in rat sperm granulomas originate from blood monocytes, exhibiting phagocytic activity and antigen presentation potential. This study used immunohistochemistry to identify macrophage populations involved in induced epididymal sperm granulomas.
Area of Science:
- Immunology
- Reproductive Biology
- Histopathology
Background:
- Sperm granulomas are inflammatory lesions characterized by degenerating sperm and immune cells.
- Macrophage involvement in sperm granuloma formation is crucial but requires detailed characterization.
Purpose of the Study:
- To investigate the origin and phenotype of macrophages within experimentally induced epididymal sperm granulomas in rats.
- To elucidate the role of different macrophage populations in the pathogenesis of sperm granulomas.
Main Methods:
- Induction of sperm granulomas in pubertal rats via repeated L-cysteine injection.
- Immunohistochemical analysis using monoclonal antibodies (ED1, ED2, OX6) to identify macrophage markers.
- Ultrastructural examination of granuloma tissues.
Main Results:
- ED1-positive macrophages (monocyte-like and epithelioid) were abundant, indicating activation.
- ED2-positive resident macrophages were largely absent.
- MHC class II-expressing cells (OX6) were present, suggesting antigen-presenting capacity.
- Ultrastructural analysis confirmed phagocytosis of spermatozoa by epithelioid macrophages.
Conclusions:
- Macrophages in rat sperm granulomas predominantly derive from blood monocytes.
- These macrophages display significant phagocytic activity and possess antigen-presenting capabilities.
- The findings contribute to understanding the immune response in sperm granuloma formation.
