| Immunodeficient mouse models are very important for biomedical research.NODSCIDIL-2rγ-/-(NSG)immunodeficient mice are defective in innate immunity-mediated rejection of human cell transplants,and are also abolished in acquired immunity.Therefore,NSG mice have been widely used in developing humanized mouse models.When compared to mouse,the physiology of rat is more similar to that of human.The rat models have apparent advantages over mouse models in the context of studing human diseases in cardiovascular system,neural system and liver.Therefore,it is important to develop NSG like rat models.we generated Prdkc-/-and IL2-rg-/-rats.We also generated transgenic rats that express human SIRPα(hSIRPα)gene.The intercross of these genetically modified rats led to the generation of NODSCIDIL2-rg-/-rats,denoted NSG rats.Like NSG mice,NSG rats lack T cells,B cells and NK cells,and do not reject human embryonic stem cells and hematopoietic stem cells.But like Prdkc-/-rats,NSG rats exhibit delayed growth and other developmental defects,and low survival and reproduction rate.These problems limit the broad ultilization of NSG rats.To resolve this bottleneck,we generated Ragl-/-rats,and through intercross,generate NODRagl-/-IL-2rγ-/-rats,denoted NRG rats.We detected and analyzed the levels of T cells,B cells and NK cells in peripheral blood of NRG and NSG rats.The expression levels of hSIRP alpha and rSIRP alpha in the remaining cells of the two groups were detected.The results showed that compared with WT rats,T cells,B cells and NK cells disappeared in NRG rats and NSG rats,while the remaining most cells were hSIRP alpha and rSIRP alpha double positive in NSG rats(more than 95%)and hSIRP alpha and rSIRP alpha double positive in NRG rats(more than 97%).There was no statistical difference between NRG rats and NSG rats.We analyzed and compared the transplantation efficiency of human embryonic stem cells between NRG rats and NSG rats.The results showed that there was no significant difference in the volume of transplanted tumors between NRG rats and NSG rats.We analyzed and compared the reproduction and development of NRG rats and NSG rats.The results showed that there were 4.75 NSG rats per fetus and 10 NSG rats per fetus.There was significant difference between the two groups.The body weight of NRG rats was significantly higher than that of NSG rats at all developmental stages.There was significant difference between the two groups.The hair of NRG rats was more lustrous,and there was no abdominal distension or diarrhea,which indicated that the growth condition was better.In conclusion,we knocked out Ragl and IL-2r gamma genes simultaneously for the first time in our newly developed NRG rats.The knockout of these two genes at the same time can achieve the immune deficiency of NSG rats and SG rats,and solve the problems of low reproductive rate and growth retardation of NSG rats and SG rats.Because the hSIRP alpha gene was also transfected into NRG rats,the transplantation efficiency of immunodeficient rats was further improved,and the transplantation effect was the same as that of NSG rats.Therefore,compared with NSG rats,NRG immunodeficient rats will be the future development direction of immunodeficient animal models. |
