Fertilization and early embryolgoy: Can Matrigel substitute for Vero cells in promoting the in-vitro development of mouse embryos?

The influences of Vero cells and the basement membrane substratumfor these cells (Matrigel^®) on the rate of hatched blastocystformation from mouse zygotes in vitro were compared. Zygotesobtained from C57BL/6xBALB/c F1 females pretreated with pregnantmare's serum gonadotrophin/human chorionic gonadotrophin matedwith BDF1 males were cultured (120 h) in human tubal fluid mediumsupplemented 0.5% with bovine serum albumin. The rates of earlyhatching and hatched blastocyst formation at 96 and 120 h ofculture were expressed as the percentage of 2-cell embryos visualizedafter the initial 24 h. The rate of total blastocyst formationdid not differ between treatment groups. However, <10% ofembryos cultured for 96 h in medium alone advanced to the hatchingstage compared with 35–40% of blastocysts cultured withVero cells or with Matrigel alone. Similarly, by 120 h of culture,only 20% of embryos cultured in medium alone developed to hatchingor hatched blastocysts compared with >70% for those embryosco-cultured with Vero cells or with Matrigel. In conclusion,Vero cells improved the rate of development of mouse embryosto hatched blastocysts during serum-free culture. Similar improvementswere seen in the presence of Matrigel alone; Matrigel is thebasement membrane substratum used for the Vero cells. Furtherstudies on the means whereby Matrigel promotes early embryonicdevelopment (e.g. appropriate combination of basement membrane-associatedgrowth factors) may lead to a safe, defined medium preparationfor the stimulation of in-vitro development of human embryos.