EXPRESSION OF GENES ENCODING ANTIOXIDANT ENZYMES IN PREIMPLANTATION MOUSE AND COW EMBRYOS AND PRIMARY BOVINE OVIDUCT CULTURES EMPLOYED FOR EMBRYO COCULTURE
Mb. Harvey et al., EXPRESSION OF GENES ENCODING ANTIOXIDANT ENZYMES IN PREIMPLANTATION MOUSE AND COW EMBRYOS AND PRIMARY BOVINE OVIDUCT CULTURES EMPLOYED FOR EMBRYO COCULTURE, Biology of reproduction, 53(3), 1995, pp. 532-540
Preimplantation embryos from a variety of mammalian species contrast m
arkedly in their response to culture in vitro. Murine preimplantation
embryos display a wider tolerance than other mammalian species to cult
ure environments, and this has contributed to the development of sever
al effective defined culture media. Embryo coculture on somatic cells
remains the most effective method of supporting reasonable rates of bo
vine preimplantation development in vitro. The patterns of gene expres
sion for several antioxidant enzymes during preimplantation murine and
bovine development were examined by use of the reverse transcription-
polymerase chain reaction technique to determine whether the different
ial developmental capacity of mammalian preimplantation embryos in cul
ture may reflect variations in the patterns of expression for a series
of antioxidant enzymes. Transcripts for catalase, CuZn-containing sup
eroxide dismutase (CuZn-SOD), Mn-SOD, glutathione peroxidase (GPX), an
d glutamylcysteine synthetase (GCS) were detected in mouse embryos at
all stages of development regardless of in vivo or in vitro developmen
t. Preimplantation cow embryos produced by in vitro procedures express
ed mRNAs for catalase, CuZn-SOD and GPX, whereas transcripts for Mn-SO
D were not detected at any stage, GCS transcripts, although present in
stages up to the morula, were not detected in cow blastocysts. Analys
is of antioxidant gene expression in both bovine primary oviductal cel
l monolayer cultures and nonattached, ciliated oviductal cell vesicle
cultures revealed a constitutive pattern of expression of all five enz
ymes for the 8-day culture interval. These experiments suggest that di
fferences in gene expression may contribute to the variation in the ab
ility of embryos to develop in vitro with respect to levels of oxygen
and dependence on coculture.