281 REDUCTION OF POLYSPERMY IN PORCINE IN VITRO FERTILIZATION BY MODIFIED SWIM-UP METHOD
C.-H. Park A , B.-S. Koo A , J.-I. Yun A , M.-G. Kim A , S.-G. Lee A , H.-Y. Son A and C.-K. Lee BA Department of Agricultural Biotechnology, Seoul National University, Suwon, South Korea;;
B Department of Agricultural Biotechnology, Xenotransplantation Research Center, Seoul National University, Suwon, South Korea. email: nabjaru@hotmail.com
Reproduction, Fertility and Development 16(2) 260-261 https://doi.org/10.1071/RDv16n1Ab281
Submitted: 1 August 2003 Accepted: 1 October 2003 Published: 2 January 2004
Abstract
In vitro production (IVP) of porcine embryos facilitates research related to biotechnology and biomedicine. Even though many attempts have been made to optimize the IVP of porcine embryos, the outcome is still unsatisfactory compared to other species, such as mouse and cattle. The high incidence of polyspermic fertilization is one of the major causes lowering the overall efficiency of porcine IVF. The common procedure for fertilization in vitro involves the co-culture of both gametes in the medium drop, which increases sperm concentration and incidence of polyspermy. Therefore, the present study was carried out to increase the efficiency of porcine IVF by reducing polyspermy using a modified swim-up method. This method modifies conventional swim-up washing by placing oocytes directly at the time of washing. Porcine oocytes were aspirated from ovaries and matured. Sperm pellet was prepared in the tube and mature oocytes were placed on a cell strainer with 70-μm pore size (Falcon 2350) at the top of the tube. After fertilization, the oocytes were fixed and stained for examination. Also, the developmental potential of fertilized embryos was measured to evaluate for the feasibility of this method. While penetration rates were similar in both methods (86.67 ± 2.36% to 83.33 ± 1.36%), there was a significant reduction of polyspermy in the modified swim-up method (17.50 ± 1.60%) compared to the control (44.1 ± 3.70%) (P < 0.05). Subsequent culture showed higher rate of blastocyst formation in the modified swim-up method (20.44 ± 0.99%) than in the control (15.73 ± 3.26%) (P < 0.05), even though the difference was not significant. These results suggest that, by controlling the number of spermatozoa reaching the oocytes, porcine oocytes might be protected from polyspermy in vitro. Also, the developmental potential of the fertilized embryos using this method could be improved by increasing the pool of spermatozoa with better quality. Further optimization of the procedure is required to impliment this method in routine porcine IVF.
