The effect of macromolecular supplementation on the surface tension of TCM-199 and the utilization of growth factors by bovine oocytes and embryos inculture

The objectives of this study were to determine the surface tension of bovin e follicular fluid (BFF) and TCM-199, and the effects of the synthetic surf actant, Twin-80, or FCS, in TCM-199 on surface tension measurements and sub sequent effects on bovine oocyte and embryo development. The surface tensio n of BFF was determined to be similar to 45.5 mN m(-1) at 25 degrees C and similar to 42.7 mN m(-1) at 39 degrees C, which was comparable to the surfa ce tension of TCM-199 containing Twin-80 (45.7 and 43.2 mN m(-1), respectiv ely). There was no difference in surface tension measurements of BFF from f ollicles 2-7 mm or 8-15 mm in diameter. Both Millipore water and phosphate buffered saline (PBS) had a surface tension measurement of 69.5 mN m(-1) at 39 degrees C. Although the presence of Twin-80 in TCM-199 resulted in a re duction in surface tension measurement as compared with unsupplemented TCM- 199, there was no effect on the number of oocytes reaching metaphase II. Ho wever, the addition of epidermal growth factor (EGF) to TCM-199 containing Twin-80 did result in increased maturation rates of oocytes in vitro. There was no effect of insulin, transferrin, and selenium (ITS), or EGF on surfa ce tension measurement of TCM-199, but significantly more zygotes cleaved a nd developed to morulae/blastocysts in TCM-199 containing both Twin-80 and growth factors. The addition of 20 mu g EGF ml(-1) to TCM-199 containing Tw in-80 was as efficacious in supporting bovine embryos in culture as was the addition of 5% or 10% fetal calf serum. This study demonstrates that surfa ce-active components in culture media positively affect bovine oocyte matur ation and embryo development in culture. Data also suggest that non-ionic s urfactants, such as Twin-80 in TCM-199, may successfully replace the surfac e-active properties but not the embryotrophic properties of serum in embryo maturation/culture media. Although commercial TCM-199 (containing Twin-SO) did not require the addition of other surface-active compounds to lower su rface tension, it did benefit from the addition of growth promoting factors , which were also provided by serum. (C) 2000 Elsevier Science B.V. All rig hts reserved.