ISSN:
0148-7280
Keywords:
oocytes
;
acidification
;
CO2
;
in vitro fertilization
;
preimplantation development
;
mouse
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
The effects of varying pH levels on superovulated mouse oocytes before in vitro fertilization, culture, and transfer were investigated. Mouse oocytes acidified for 1 hour with 20% CO2 (pH 6.9) exhibited a wide range of alterations. Five hours after insemination, 25% of these eggs showed different degrees of cytolysis and their perivitelline space contained numerous spermatozoa. At 12 hours normal-looking eggs from this group showed a higher proportion of polypronuclear zygotes than the control group (exposed, 51%; controls, 18%). Acidification thus markedly increased the permeability of the zona pellucida and/or interfered with the normal block to polyspermy. Fewer eggs achieved the two-cell stage among groups submitted to acidotic pH levels (6.9 to 6.6). In contrast, alkaline conditions (pH 7.8) did not reduce the proportion of two-cell embryos. However, only eggs maintained at pH 7.5 were capable of producing 80% of blastocysts. In other groups developmental blockage occurred mainly between stages 2 and 4. A significant reduction was found in the proportion of recipient females becoming pregnant after intrauterine transfer of blastocysts originating from CO2-treated oocytes. This difference might be related to the existence of a large polyploid population among experimental eggs.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrd.1120130305
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