Page 141 - PCC02

PHYSICAL FACTORS
CO2
• Is essential to maintain the pH of bicarbonate buffered medium
• Incorporated into protein and nucleic acids by the mouse
embryo at all stages prior to implantation
• Even though culture systems for the pre-implantation mammalian embryo employ 5%C02 coupled with 25mM bicarbonate concentration, analysis of the uterine environment for various mammalian species vary up to 10%
• Possible beneficial effect of a high CO2% is due to the decrease in the pH of the medium as the beneficial effect of increased CO2 could be replicated with a weak acid
CO2
• pH of media containing 25mM bicarbonate that is equilibrated in a CO2 environment can be calculated using the Henderson- Hasselbach equation
• At 5% CO2 the pH of the 25mM bicarbonated medium is 7.45, while a 6% CO2 is required to maintain the external pH of the medium around 7.4
• Optimal CO2% for human embryo development has yet to be determined, however the CO2 % is related to the pH of the medium that needs to be considered
• Measurement of CO2% should be performed with high accuracy CO2 analysis meters
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PRECONGRESS COURSE 02 I BARCELONA, SPAIN – 1 JULY 2018 141