Comparison of maturation, fertilization, development, and gene expression of mouse oocytes grown in vitro and in vivo.
OBJECTIVE
To investigate the difference of in vitro and in vivo grown oocytes, we compared maturation, fertilization, development, and maternal gene expression from both in vitro and in vivo grown mouse oocytes.


METHODS
The preantral follicles isolated from 12-day-old mice were cultured on Transwell-COL membrane inserts. After culture, maturation, fertilization, and developmental rates were assessed. RT-PCR (reverse transcription-polymerase chain reaction) was performed to examine the expression of beta-actin, GDF-9, and IGF-II in matured oocytes.


RESULTS
No difference in the nuclear maturation was detected between in vitro and in vivo grown oocytes, but the mean oocyte diameter of the in vitro group was smaller than that of the in vivo group. The fertilization rate was significantly lower in the in vitro group than in the in vivo group (p < 0.05). The capacities of in vitro grown oocyte to cleave and develop to blastocysts were significantly lower than those of the in vivo grown oocytes (p < 0.001). Moreover, blastocyst of in vitro group had fewer total cells than those of in vivo group (p < 0.05). In regards to the expression of genes in mature oocytes, growth differentiation factor-9 (GDF-9) expression was similar between the two groups, but beta-actin was significantly reduced in the in vitro group compared to the in vivo group. Particularly, the expression of insulin-like growth factor II (IGF-II) was not found in the in vitro grown oocytes.


CONCLUSIONS
These results showed that in vitro grown oocytes did not have the same developmental capacity as in vivo grown oocytes. We assume that the aberrant expression of maternal-derived genes in the in vitro grown oocytes may cause the poor embryo viability.
Kim
Dong-Hoon
DH
Animal Biotechnology Division, National Livestock Research Institute, Suwon, Korea. kdh1010@rda.go.kr
Ko
Duck-Sung
DS
Lee
Hoi-Chang
HC
Lee
Ho-Joon
HJ
Park
Won-Ii
WI
Kim
S Samuel
SS
Park
Jin-Ki
JK
Yang
Byoung-Chul
BC
Park
Soo-Bong
SB
Chang
Won-Kyong
WK
Lee
Hoon-Taek
HT
D000199:Actins / Q000235:genetics; D000818:Animals; D002455:Cell Division; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000502:physiology*; D004624:Embryo Transfer; D005260:Female; D005306:Fertilization / Q000502:physiology*; D005786:Gene Expression Regulation; D007335:Insulin-Like Growth Factor II / Q000235:genetics; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009865:Oocytes / Q000166:cytology* / Q000502:physiology*; D006080:Ovarian Follicle / Q000166:cytology; D011247:Pregnancy; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013084:Sperm-Ovum Interactions; D015044:Zona Pellucida / Q000502:physiology / Q000648:ultrastructure
D000199:Actins; D007335:Insulin-Like Growth Factor II