Pig has been known to be one of the most feasible animals as a bioreactor to produce pharmaceuticals in milk and as a mediator in xenotransplantation research. Previously, we generated transgenic pigs for both purposes, which were expressing Factor 8, vWF, hTPA, and hEPO in milk, along with expression of MCP at GalT gene locus (GalT-MCP/-MCP) as well as expressing MCP at GalT gene loci with CD73 expression (GalT-MCP/+/CD73). In this study, we performed comparative analyses of sperm parameters between wild type male (WT) pig and those transgenic males to examine the effects of transgenes integrated into the pigs on motility, morphology, viability, and acrosome integrity of the spermatozoa. Our results showed that the rates of actively motile spermatozoa of WT, Factor 8, vWF, hTPA, hEPO, GalT-MCP/+/CD73, and GalT-MCP/-MCP pigs were 85.0%, 83.3%, 82.5%, 83.3%, 82.5%, 77.5%, and 78.7%, respectively. Whereas, the rates of morphologically normal spermatozoa of WT, Factor 8, vWF, hTPA, hEPO, GalT-MCP/+/CD73, and GalT-MCP/-MCP pigs were 90.0%, 80.0%, 80.0%, 83.3%, 85.0%, 91.8%, and 80.8%, respectively. In addition, the viability in spermatozoa of WT, Factor 8, vWF, hTPA, hEPO, GalT-MCP/+/CD73, and GalT-MCP/-MCP pigs were 93.9%, 82.4%, 89.9%, 83.9%, 87.4%, 92.8%, and 83.6%, respectively. The rates of spermatozoa with normal acrosome integrity in WT, Factor 8, vWF, hTPA, hEPO, GalT-MCP/+/CD73, and GalT-MCP/-MCP pigs were 98.1%, 98.6%, 98.6%, 98.7%, 98.1%, 99.5%, and 95.1%, respectively. There were no significant differences in motility, morphology, viability, and acrosome integrity of the spermatozoa among WT, Factor 8, vWF, hTPA, and hEPO, GalT-MCP/+/CD73, and GalT-MCP/-MCP pigs. These mean that neither random integration nor targeted integration of the transgene into chromosome of pig effect on characteristics of spermatozoa. Ultimately, the transgenic male pigs subjected in this study could apply to propagate their progenies for production of human therapeutic proteins and advancing the xenotransplantation research.

Pigs have been extensively used as mediators of xenotransplantation research. Specifically, the Massachusetts General Hospital (MGH) miniature pig was developed to fix major histocompatibility antigens for use in xenotransplantation studies. We generated transgenic pigs for xenotransplantation using MGH pigs. However, it has not been studied yet whether these pigs show similarity of reproductive physiological characteristics to wild types of MGH miniature pig. In this study we analyzed the estrous cycles and pregnancy characteristics of wild type (WT) and transgenic MGH miniature pigs, which were α1,3-galactosyltransferase (GalT) heterozygous and homozygous knock-out, and membrane cofactor protein (MCP) inserted in its locus, GalT-MCP/+ and GalT-MCP/-MCP pigs. Estrous cycles of WT, GalT-MCP/+ and GalT-MCP/-MCP pigs were 20.9±0.74, 20.1±1.26, and 17.3±0.87 days, respectively, and periods of estrous were 3.2±0.10, 3.1±0.12, and 3.1±0.11 days. The periods of gestation of WT, GalT-MCP/+ and GalT-MCP/-MCP pigs were 114.2±0.37, 113.3±0.67, and 115.4±0.51 days, respectively. Litter sizes of WT, GalT-MCP/+ and GalT-MCP/-MCP pigs were 4.8±0.35, 4.8±1.11 and 3.0±0.32 respectively. There were no significant differences on estrous cycle, periods of estrous and gestation, and litter size among WT, GalT-MCP/+ and GalT-MCP/-MCP pigs, meaning that GalT knock-out and additional expression MCP of the MGH miniature pig did not effect on reproduction traits. These results provide relevant information to establish breeding system for MGH transgenic pig, and for propagation of GalT-MCP/-MCP pig to supply for xenotransplantation research.

Transplantation is considered to be a very useful approach to improve human welfare and to prolong life-span. Heterologous organ transplantation using pig organs which are similar to human beings and easy to make mass-production has known as one of the alternatives. To ensure potential usage of the pig organ for transplantation application, it is essentially required to generate transgenic pig modifying immuno-related genes. Previously, we reported production of heterozygous α 1,3-galactosyltransferase (GalT) knock-out and human membrane cofactor protein (MCP) expressing pig (GalT-MCP/+), which is enforced for suppression of hyperacute and acute immunological rejection. In this study, we reported generation of homozygous pig (GalT-MCP/-MCP) by crossbreeding GalT-MCP/+ pigs. Two female founders gave birth to six of GalT-MCP/-MCP, and seven GalT-MCP/+ pigs. We performed quantitative real-time PCR, western blot, and flow cytometry analyses to confirm GalT and MCP expression. We showed that fibroblasts of the GalT-MCP/-MCP pig do not express GalT and its product Gal antigen, while efficiently express MCP. We also showed no expression of GalT, otherwise expression of MCP at heart, kidney, liver and pancreas of transgenic pig. Taken together, we suggest that the GalT-MCP/-MCP pig is a useful candidate to apply xenotransplantation study.