| In recent years, large numbers of transgenic and knockout mice have been generated and it is anticipated that the numbers of lines will continue to increase as scientists further investigate the genome and gene functions. Cryopreservation provides an efficient and effective way to maintain these unique genetically modified rodent lines. However, there is a great risk of transmitting various diseases via the cryopreserved gametes and embryos. Microbial pathogens may come from both male donors (semen) and female donors (oocytes and embryos). Although pathogens associated with gametes and embryos of cattle and swine have been evaluated to a great extent, very little research has been conducted on microorganisms in mouse germ cells. Our hypothesis is that microbial pathogens may associate with mouse gametes and embryos. To investigate which of the commonly found murine pathogens contaminate mouse gametes and embryos, seven commonly found pathogens in research mice were evaluated in semen, oocyte-cumulus complexes and embryos collected from naturally infected mice in the first part of my study. These seven pathogens are: mouse parvovirus, Helicobacter, Mycoplasma pulmonis, Pasteurella pneumotropica, murine norovirus, mouse hepatitis virus and Theiler's murine encephalomyelitis virus. Five pathogens, mouse parvovirus, Helicobacter, mouse hepatitis virus, murine norovirus, Theiler's encephalomyelitis virus, were found in mouse semen, and mouse parvovirus, Helicobacter, mouse hepatitis virus, murine norovirus were found in mouse oocytes and embryos. These findings indicate there is potential risk of transmitting microbial pathogens via cryopreserved gametes and embryos.;Recent advances in the methodologies for cryopreservation of mouse spermatozoa have opened up a number of opportunities for storage of transgenic mouse strains and rederivation by assisted reproductive technologies (ART) such as in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), embryo transfer, ovarian tissue transplantation. Mouse parvovirus is one of the prevalent pathogens in research animals and mouse gametes and embryos as well. Therefore, the second part of this study focused on evaluating mouse parvovirus and determining the effect of infection in male mice on in vitro fertilization including how it will change fertilization rate, cleavage rate and embryonic development and whether Mouse parvovirus was transmitted to embryos at blastocyst stage. Our hypothesis is Moue parvovirus carried by sperm transmits to blastocysts and affects fertilization, cleavage and embryonic development. In this study, in vitro fertilization was performed with sperm collected from ICR mice that were inoculated with Mouse parvovirus-1 and oocytes collected from ICR uninfected mice. In control group, IVF was performed by using sperm and oocyte collected from ICR uninfected mice. We did not find mouse parvovirus-1 infection in male mice transmission to in vitro produced embryos and there was no effect on fertilization rate, cleavage rate and embryonic development during in vitro fertilization. |
