Pseudopregnancy and reproductive cycle synchronisation cannot be induced using conventional methods in the spiny mouse (Acomys cahirinus)

Reprod Fertil Dev. 2020 Feb;32(4):363-372. doi: 10.1071/RD18506.

Abstract

The menstruating spiny mouse is the first rodent identified to exhibit natural spontaneous decidualisation, cyclical endometrial shedding and regeneration. While the spiny mouse shares several primate-like characteristics in its reproductive biology, it has not been established whether pseudopregnancy can be induced or if its cycles can be synchronised as in non-human mammals. Here we describe attempts to induce pseudopregnancy and synchronisation of menstrual cycles (i.e. Whitten effect) in spiny mice. Virgin females (n=3-8 per group) underwent one of the following procedures to induce pseudopregnancy: daily vaginal lavage only (control), progesterone injection, mechanical stimulation of the cervix and sterile mating. A separate cohort was also exposed to male-soiled bedding to assess the Whitten effect. Pseudopregnancy was deemed successful if females presented with extended (>12 consecutive days) leukocytic vaginal cytology. No female from any method of induction met this criterion. In addition, the menstrual cycles of a group of six females could not be synchronised, nor immediate ovulation induced via exposure to male-soiled bedding. These responses indicate that the spiny mouse does not behave as a typical rodent. Like higher-order primates, the spiny mouse exhibits a relatively rare reproductive strategy, of failure to show pseudopregnancy or cyclical synchronisation. This is further endorsement of the use of this species as a versatile animal model for translational studies of menstruation and fertility.

MeSH terms

  • Animals
  • Endometrium / drug effects
  • Endometrium / physiology*
  • Female
  • Male
  • Menstrual Cycle* / drug effects
  • Murinae
  • Ovulation* / drug effects
  • Periodicity
  • Physical Stimulation
  • Pregnancy
  • Progesterone / administration & dosage
  • Pseudopregnancy / etiology
  • Pseudopregnancy / physiopathology*
  • Reproduction* / drug effects
  • Species Specificity
  • Vasectomy

Substances

  • Progesterone