In vivo fertilization improved the cryotolerance and developmental ability of vitrified-warmed rat fertilized oocytes.

The cryopreservation of rat embryos is useful for efficiently archiving rat resources in bioresource repositories. The cryopreserved fertilized oocytes can be quickly reanimated to rats with homozygous mutations using embryo transfer. In addition, cryopreserved rat fertilized oocytes are easier to transport than live animals.

High-concentration bovine serum albumin enhances fertilization ability of cold-stored rat sperm.

Cold transport of the cauda epididymides is a useful technique for shipping laboratory rat sperm. Cold transport of rat sperm avoids potential risks of microbiological infection, animal escape or death, and animal welfare issues. Previously, we reported that a cold-storage solution containing dimethyl sulfoxide and quercetin maintained the fertility of cold-stored rat sperm.

Time elapsed between ovulation and insemination determines the quality of fertilized rat oocytes.

Genetically modified rats are valuable models in human disease research. We recently developed an improved system for rat sperm cryopreservation and in vitro fertilization (IVF) that facilitates the efficient production and preservation of genetically modified rats. In the IVF procedure performed using frozen-thawed rat sperm, the IVF schedule is fixed to ensure timely hormone administration and oocyte collection.

Observation of the in vitro fertilization process in living oocytes using frozen-thawed sperm in rats.

Previous studies have observed the fertilization process in rats using whole-mount preparation at different time-points after insemination. However, very few reports have described the various events during the fertilization process using an inverted microscope without whole-mount. Moreover, to the best of our knowledge, no reports have described the observation of changes in sperm motility associated with sperm penetration into oocytes.

Optimized protocols for sperm cryopreservation and in vitro fertilization in the rat.

Laboratory rats have been used in biomedical research for over 170 years. Recently, genome editing technology has facilitated the generation of genetically modified rats worldwide. This development has increased the demand for efficient preservation and production of rat resources.

Quercetin-treated rat sperm enables refrigerated transport with motility and fertility for five days.

Shipment of laboratory rats between animal facilities is frequently performed using special containers. However, the shipment of live animals is associated with potential risks of infectious diseases, escape and death during shipment and animal welfare issues. The transport of cold-stored sperm avoids such risks; however, there have been no reports on cold storage of rat sperm.