Non-surgical embryo transfer with the NSET~(TM) device is a 3Rs refinement technique that reduces stress in CD-I mice

摘要

Non-surgical embryo transfer (NSET) can be used to transfer blastocysts to recipient mice during the generation of transgenic mice, after cryopreservation or embryos, after in-vitro fertilisation and during rederivation of mouse strains. Non-surgicalembryo transfer is a refinement (one of the 3Rs) of the surgical embryo transfer procedure. The NSET~(TM) device is a small tapered catheter that attaches to a P2 pipette and deposits embryos directly into the mouse's uterine horn. Use of an NSET~(TM) device in mice should substantially reduce pain, suffering and recovery time of mice as the surgical procedure is replaced with an alternative method. No anaesthesia is required for nonsurgical embryo transfer and the mice require no postprocedure recovery. Because the NSET procedure is non-surgical and does not need anaesthesia, we hypothesised that use of the NSET~(TM) device is less stressful than surgery for the mouse. We therefore compared the stress responses of pseudopregnant CD-1 mice (2.5 days post coitum) following uterine embryo transfer surgery and nonsurgical embryo transfer procedures using the NSET~(TM) device. ELISA analysis was used to quantify levels of faecal cortisone, a biomarker of stress.