Quantitative microscopic changes in the mole rat testes during an annual cycle

Ahuva Gottreich, Ilan Hammel, Leah Yogev, Joseph Terkel*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Background: The mole rat Spalax ehrenbergi is a solitary, aggressive subterranean rodent. The present study summarizes a year‐round investigation of histological changes and sperm production in the mole rat testes. Methods: The testes were processed for routine histological examination. Tissues were fixed in Bouins' solution embedded in paraffin blocks and stained by hematoxylin‐eosin. A systemic sampling approach was used to photomicrograph the tissues for histomorphometric assessment. Results: Quantitative morphometry provided parameters indicating the activity of the tubuli testes during the year. The volume fraction of testes interstitial tissue from animals kept in captivity was unimodal and demonstrated an almost 3‐fold increase (from Vv = 0.19 ± 0.02 μm3/μm3 in October to 0.55 ± 0.05 μm3/μm3 in November) (i.e., early winter). The testes tubuli Vv of these animals demonstrated a significant decrease (from 0.75 ± 0.08 μm3/μm3 in October to 0.37 ± 0.04 μm3/μm3 in November). The testes tubuli star‐volume demonstrated an annual bi‐modal distribution, during winter (November‐February, v* = 0.075 ± 0.015 μm3) and summer (July‐August, v* = 0.085 ± 0.016 μm3); the lowest star‐volume was found in April (v* = 0.017 ± 0.004 μm3 in the field group). The testes tubuli revealed the entire sperm differntiation process throughout the year, from spermatogenesis (cells at all stages) to observation of mature spermatozoa, even though the mole rat is fertile only once a year during the winter. An increase in spermatogenesis and sperm production occurs during winter (Novermber‐December) and autumn (April‐May). Conclusion: It would appear that although changes in spermatogenesis and tissue structure are found during the annual cycle, the males none the less have a fecundity potential throughout the entire year. ± 1995 Wiley‐Liss, Inc.

Original languageEnglish
Pages (from-to)195-199
Number of pages5
JournalAnatomical Record
Issue number2
StatePublished - Oct 1995


  • Annual cycle
  • Fertility
  • Light microscopy
  • Sperm production
  • Star volume
  • Subterranean rodent
  • Volume fraction


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