Plasminogen activator production and enhanced development in medium containing plasminogen or plasmin by rabbit embryos in vitro

A series of experiments was conducted to evaluate plasminogen activator production and effects of supplementing culture medium with plasminogen or plasmin on development of rabbit embryos in vitro. In Expt 1, 495 one- to two-cell embryos were cultured in Ham's F-12 with 15 mg BSA ml \m=-\1 containing 0, 30, 60 or 120 pg porcine plasminogen ml \m=-\1 or 0, 75, 150 or 300 \g=m\grabbit plasminogen ml \m=-\1. Percentages of embryos developing to the expanded blastocyst, hatching blastocyst and hatched blastocyst stages were greater(P < 0.05) in medium with 120 \g=m\gporcine plasminogen ml \m=-\1 than in the absence of plasminogen. More (P < 0.05) embryos developed to the blastocyst, expanded blastocyst and hatching blastocyst stages in medium with 300 \g=m\grabbit plasminogen ml \m=-\1 than in the absence of plasminogen. In Expt 2, 216 one- to two-cell embryos were cultured in medium with 0, 30, 60 or 120 \g=m\gporcine plasminogen ml \m=-\1 for 96 h, fixed and stained with haematoxylin and eosin, and the number of cells determined. No differences (P> 0.05) were observed in number of cells of morulae but blastocysts developing in medium with 120 \g=m\g porcine plasminogen ml\m=-\1had more (P < 0.05) cells (109.9 \m=+-\10.4) than did blastocysts in medium with either 0 (69.4 \m=+-\14.6) or 30 \g=m\gporcine plasminogen ml \m=-\1 (73.3 \m=+-\12.2). In Expt 3, 144 one- to two-cell embryos were cultured in medium with 0, 13 or 45 \g=m\gporcin