THURSDAY, Sept. 6 (HealthDay News) -- Scientists have discovered that sperm stem cells cluster around blood vessel branch points in the testes of mice, and may be a potential "microenvironmental niche," according to a study published online Sept. 6 in Science.
Shosei Yoshida, of Kyoto University in Japan, and colleagues used time-lapse imaging of fluorescent protein-labeled sperm stem cells and three-dimensional modeling to determine the localization of undifferentiated spermatogonia in mice.
The researchers showed that undifferentiated spermatogonia clustered around interstitium-rich branch points of blood vessels within the seminiferous tubules, suggesting that these areas act as a microenvironmental niche. When researchers disrupted the vasculature structure, the spermatogonia migrated to new positions so that they were still adjacent to these regions.
The authors postulate that the mammalian germline niche develops based on the formation of blood vessels.
"A vasculature-oriented niche formation has several attractive features. It allows niches to form at regular intervals all through the seminiferous tubule loops independently from their length. Additionally, new niches could be added as the tissue increases in size, or following tissue damage and revascularization," the authors write. "Such niche plasticity could be particularly beneficial for continuous spermatogenesis during long reproductive periods of mammalians."
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