Oestrus cycle of the Desert hamster (Phodopus roborovskii, Satunin, 1903)

Abstract

The Desert hamster, Phodopus roborovskii, is one of the lesser-known laboratory animal models and therefore knowledge of its reproductive system and physiology is limited. This study investigated the time course of vaginal and behavioural oestrus cycles by means of vaginal smear cytology, serum luteinizing hormone (LH) levels, wheel-running activity patterns, and pairing tests. The oestrus cycle lasts between four and six days and follows a pattern rather similar to that described for other rodent species. An important finding of this study is the existence of a fifth cycle stage between pre-oestrus and oestrus, the so-called early oestrus. Early oestrus differs from pre-oestrus by a complete lack of leucocytes in the vaginal cytology and a dramatic increase of serum LH levels just before activity onset. The early oestrus stage lasts 4-6 h, but was not observed in every female. When present it affects the length of the whole oestrus cycle. With early oestrus the pre-oestrus stage lasts only 14-18 h and the total length of the oestrus cycle length is four days. Without early oestrus, the pre-oestrus is prolonged to 18-36 h and the oestrus cycle length varies between four and six days. Desert hamsters showed only subtle oestrus-correlated changes in wheel-running activity, i.e. they failed to show the characteristic scalloping of activity onset, but showed prolonged activity during early oestrus. Pairing tests revealed characteristic changes in the relative frequencies of socio-positive, neutral, aggressive and sexual behaviour during the course of the oestrus cycle, with an elevated level of sexual behaviour during oestrus.Keywords oestrus cycle, vaginal smears, activity, behaviour, luteinizing hormone (LH) Hormonal changes accompanying the oestrus cycle have been investigated in great detail in rodent laboratory animals because they affect the behaviour and physiology of female animals in a complex manner.

Spermatogenesis in the Roborovski hamster (Phodopus roborovskii) and the Chinese hamster (Cricetulus griseus)

“…For the first time, we present details about spermatogenesis and the morphological characteristics of male reproductive organs and sperm cells at different stages in the Roborovski hamster. Following the detailed descriptions of the female estrous cycle, 20 our study advances the understanding of the complexity of the reproductive system in hamsters. Furthermore, we present a novel tool to analyze the DCSE of the Roborovski hamster that can be easily adapted to understand the DCSE of other species.…”

“…[15][16][17] Previous studies found that SARS, 1 of the 3 epidemic coronaviruses to emerge in the past 20 years and that shows similar clinical presentations to COVID-19, 18 could cause orchitis 19 and focal testicular atrophy. 20 Considering the tens of millions of COVID-19 cases and that men are more vulnerable to COVID-19 than women, [21][22][23] it is imperative to determine the effect of COVID-19 on male reproduction. 24 Several studies have been performed on this topic.…”