Effect of vitrification on mitochondrial distribution and membrane potential in mouse two pronuclear (2-PN) embryos.
The present study was designed to investigate the effect of vitrification on mitochondrial distribution, membrane potential (Deltapsi) and microtubule distribution in mouse 2-PN embryos, as well as to document the relationship between mitochondrial distribution and developmental ability of those embryos. Mitochondrial distribution was examined by fluorescence microscopy technology. Results indicated that: (1) The rate of mitochondrial ring formation around pronuclei in vitrified 2-PN embryos was significantly lower than in fresh ones (67.3 +/- 3.0% vs. 84.9 +/- 3.1%) (P < 0.05). (2) Blastocyst development rate of vitrified 2-PN embryos without mitochondrial rings (61.7 +/- 4.5%) was significantly lower than that of vitrified embryos with mitochondrial rings (82.1 +/- 2.8%). (3) Following staining by 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl-imidacarbo-cyanine iodide (JC-1), most red-colored mitochondria (high Deltapsi) were distributed peripherally around pronuclei and along cell membranes of fresh 2-PN embryos. Conversely, red-colored mitochondria were greatly diminished in vitrified embryos, with green mitochondria (low Deltapsi) evenly distributed throughout the cytoplasm. The proportion of fresh 2-PN embryos with obvious aggregation of high Deltapsi mitochondria (84.2 +/- 2.2%) was significantly higher than that of vitrified embryos (26.7 +/- 3.0%) (P < 0.05). (4) The proportion of fresh embryos with microtubules distributed around pronuclei (83.5 +/- 3.4%) was similar to that of vitrified embryos (74.7 +/- 2.5%). In conclusion, vitrification affected mitochondrial distribution and decreased the mitochondrial membrane potential in mouse 2-PN embryos, events which may affect subsequent developmental viability of such embryos.
Zhao
Xue-Ming
XM
Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, and State Key Laboratories for Agrobiotechnology, China Agricultural University, Beijing 100193, P.R. China.
Fu
Xiang-Wei
XW
Hou
Yun-Peng
YP
Yan
Chang-Liang
CL
Suo
Lun
L
Wang
Yan-Ping
YP
Zhu
Hua-Bin
HB
Dinnyés
Andras
A
Zhu
Shi-En
SE
D000704:Analysis of Variance; D000818:Animals; D001755:Blastocyst / Q000166:cytology; D015925:Cryopreservation; D004622:Embryo, Mammalian / Q000166:cytology / Q000648:ultrastructure*; D005615:Freezing; D053078:Membrane Potential, Mitochondrial / Q000502:physiology; D051379:Mice; D008856:Microscopy, Fluorescence; D008858:Microscopy, Phase-Contrast; D008870:Microtubules / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism* / Q000502:physiology; D009028:Morula / Q000166:cytology