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Activin A and Follistatin Regulate Developmental Competence: RESULTS(3)

Furthermore, the percentages of embryos that developed to morulae (29%) and blastocysts (18%) in the culture with a combination of 10 ng/ml activin A and 100 ng/ ml follistatin were significantly lower (p < 0.01) than those in the control. The total numbers of cells in morulae and blastocysts obtained by culture with activin A and/or fol-listatin are shown in Table 1. There was no significant difference in the total number of cells in morulae or blastocysts among the treatments. antibiotic levaquin

Effects of the Developmental Stages of Embryos Affected by Activin A or Follistatin

Figure 4 shows the effects of adding either 10 ng/ml activin A or 10 ng/ml follistatin at various developmental stages on the development in vitro of embryos to the blastocyst and hatched blastocyst stages. Addition of activin A to medium at the 1-cell, 2-cell, 3- to 4-cell, and 5- to 8cell stages significantly increased (p < 0.05) the percentage of embryos that developed to blastocysts (32%, 43%, 45%, and 52%, respectively) compared with no addition (24%, 32%, 33%, and 39%, respectively) and compared with addition of follistatin (1б%, 22%, 24%, and 30%, respectively) at each stage. Furthermore, the percentage of embryos at these stages that developed to blastocysts with addition of follistatin was significantly lower (p < 0.05) than the percentage obtained with no addition. In contrast, addition of activin A or follistatin at the 9- to 16-cell and morula stages did not affect the percentage of embryos that developed to blastocysts . There was no significant difference in hatching rate of embryos among the treatments (Fig. 4, B-G), except that the percentage of zygotes that hatched was significantly higher (p < 0.05) with addition of activin A than with addition of follistatin.
TABLE 1.

Addition Total number of cells in (n)
Morulae [120 h]b Blastocysts [175 h]b
None 29.0 ± 9.1 150.9 ± 54.3
10 ng/ml Follistatin 2 7.9 ± 7.5 130.6 ± 36.1
10 ng/ml Activin A 28.4 ± 9.1 153.1 ± 54.7
10 ng/ml Activin A + 10 ng/ml follistatin 27.4 ± 8.3 149.9 ± 58.9
10 ng/ml Activin A + 100 ng/ml follistatin NTc 140.3 ± 49.0

a Data are pooled from 5-8 replicates; values are mean ± SD. bTime after in vitro insemination. c Not tested.