MICROMANIPULATION OF MOUSE GAMETES WITH LASER MICROBEAM AND OPTICAL TWEEZERS

Micromanipulation of mouse gametes with a commercially available compa ct laser microbeam system was studied. Both the normal in-vitro fertil ization (IVF) group and the laser zona dissection (LZD) group were tes ted under normal (2X10(6) motile spermatozoa/ml) and low (500 000 moti le spermatozoa/ml) insemination conditions. Subzonal insemination (SUZ I) was also tried in a small group of gametes and the results were com pared with those of the low insemination groups. Fertilization rates a nd blastocyst formation rates for the IVF and the LZD-treated groups w ere respectively 53 and 60% and 60 and 78%, which were not significant ly different. However, under low insemination conditions, the results were significantly better in the LZD-treated group (58% fertilization rate and 83% blastocyst formation rate) compared to the results of the IVF group (33 and 48%) (P < 0.05), The SUZI-treated group showed the lowest fertilization rate (18%). No significant difference between the LZD and the IVF group was observed with respect to parthenogenetic ac tivation, LZD has a beneficial effect on fertilization rates in cases of reduced sperm quality.