Simple induction of pseudopregnancy by artificial stimulation using a sonic vibration in rats

Self Cite

Psuedopregnancy for embryo transfer (ET) is usually induced in rats by mating with vasectomized males. Previously, we successfully induced pseudopregnancy using sonic vibration instead (Easy-ET method). The transferred embryos developed normally. Conventionally, stimulation is performed 7 × 30 s with 5 min intervals at the day before ET. However, this protocol is time-consuming because it imitates natural mating behavior. Here, we investigated pseudopregnancy induction with shorter stimulation times. Stimulation was performed 2 × 30 s, with 30 s intervals at the proestrus stage at the day before ET. Of the transferred pronuclear or two-cell embryos, 43% or 62% developed normally, respectively. Furthermore, 67% or 68% of transferred pronuclear or two-cell embryos in rats at estrus stage stimulated on the day of ET developed normally, respectively. Pseudopregnancy was successfully induced with shorter stimulation. Furthermore, this protocol may be used to perform a single-day stimulation and ET operation at the estrus stage.

Section: Discussionmentioning

confidence: 99%

“…A self-made sonic vibrator (Fig. 1 A) 23 was used for artificial stimulation. The probe of the vibrator was inserted into the vagina of the female.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Successful pseudopregnancy of rats by short period artificial stimulation using sonic vibration

Endo

Tsunoda

Tawara

et al. 2022

Self Cite

“…However, this procedure requires a large breeding space, and it is costly to maintain a sufficient number of healthy females and vasectomized males to induce pseudopregnancy. We recently developed method, named Easy-ET, to induce pseudopregnancy in female rats by artificial stimulation using sonic vibration instead of vasectomized males 27 . The production of female mice with pseudopregnancy induced using sonic vibration was as efficient as rats.…”

Section: Introductionmentioning

confidence: 99%

Successful induction of pseudopregnancy using sonic vibration in mice

Wake

Endo

Tsunoda

et al. 2023

Self Cite

Embryo transfer (ET) is an essential reproductive technology for the production of new animal strains and maintenance of genetic resources. We developed a method, named Easy-ET, to induce pseudopregnancy in female rats by artificial stimulation using sonic vibration instead of mating with vasectomized males. This study examined the application of this method for the induction of pseudopregnancy in mice. Offspring were obtained from two-cell embryos transferred into females with pseudopregnancy induced using sonic vibration in proestrus on the day before embryo transfer. Furthermore, high developmental rates of offspring were observed when pronuclear and two-cell embryos were transferred to females in estrus that were stimulated on the day of embryo transfer. Genome-edited mice were also obtained using frozen-warmed pronuclear embryos with clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated system (Cas) nucleases introduced using the technique for animal knockout system by electroporation (TAKE) method, which were transferred to females with pseudopregnancy induced on the day of embryo transfer. This study demonstrated that induction of pseudopregnancy by sonic vibration was also possible in mice.

“…In contrast, several efficient methods for producing pseudopregnant female rats using exogenous hormone treatment have been described previously [23][24][25][26] .…”

mentioning

confidence: 99%

Scheduled simple production method of pseudopregnant female mice for embryo transfer using the luteinizing hormone-releasing hormone agonist

Sari

Hilario

Yuri

et al. 2022

The use of mice as experimental animal models has been a practice since the development of genetically engineered mouse models (GEMMs) in the early 1980s. New technologies, including genome editing, have helped in the time- and cost-efficient generation of GEMMs. However, methods for preparing pseudopregnant females, essential for the generation of GEMMs, remain less advanced. This study proposes a new method to achieve simple production of pseudopregnant female mice using a luteinizing hormone-releasing hormone agonist (LHRHa). A 20 µg LHRHa/mouse was identified as the best dose for inducing estrus synchronization. However, the frequency of copulation was 40% on a single injection. With sequential injections of 20 µg LHRHa/mouse on Days-1 and -2, followed by pairing on Day-5, 74% of LHRHa-treated females copulated with male mice. Moreover, LHRHa treatment did not affect fetal and postnatal development. Eventually, successful generation of offspring via embryo transfer was attained using LHRHa-treated pseudopregnant females. LHRHa administration method is efficient in producing pseudopregnant female mice for the generation of GEMMs, and we expect that it will contribute towards advancing the clinical research.