Author/Editor		Kovačič, B; Vlaisavljević, V
Title		Primerjava ultrahitrega in počasnega zamrzovanja mišjih zarodkov
Translated title		Comparison of ultrarapid and slow freezing of mouse embryos
Type		članek
Source		Zdrav Vestn
Vol. and No.		Letnik 64, št. 7-8
Publication year		1995
Volume		str. 413-7
Language		slo
Abstract		Background. The aim of the study was to compare the ultrarapid method of embryo freezing and the technique of slow cooling by means of a portable computer-controlled device Freeze Control L863 (Cryologic, Australia). Methods. Mouse embryos of different preblastular stages were frozen, and their morphologic survival immediately after thawing as well as their capacity for further development under in vitro conditions were evaluated. The success of freezing procedures was expressed by the percentage of thawed embryos which had reached the blastocyst stage - actual survival. Results. Only 40.2 percent (51/127) of four-cell embryos (p less th. 0.001) and 78.4 percent (76/97) of eight-cell embryos (p less th. 0.025) actually survived ultrarapid freezing. Slow freezing proved successful in 76.9 percent (103/134) of four-cell embryos (p less th. 0.01) and in 72.4 percent (113/156) of eight-cell embryos (p less th. 0.001). Embryos having less than half of their blastomeres intact after thawing also developed to blastocysts. Among such damaged embryos, vitality was conserved in 47.4 percent (9/19) of ultrarapidly frozen embryos and in 44.1 percent (15/34) of slowly frozen embryos. Conclusions. After ultrarapid freezing, early embryonal stages with larger blastomeres show a poor survival rate. In slow cooling using the controlled freezing device, the size of blastomeres bears no effect on the success of the procedure and is therefore more appropriate for clinical application in human material.
Summary		Izhodišča. Smoter raziskave je bil primerjati metodo ultrahitrega in počasnega zamrzovanja zarodkov in uporabnost prenosne računalniško vodene zamrzovalne aparature Freeze Control L863 (Cryologic, Australia). Metode. V poskusu smo zamrzovali mišje zarodke različnih predblastularnih stadijev in opazovali njihovo morfološko preživetje takoj po odmrznjenju in sposobnost nadaljnjega razvoja v pogojih in vitro. Uspešnost zamrzovalnih postopkov smo izrazili z deležem odmrznjenih zarodkov, ki so dosegli stadij blastociste - dejansko preživetje. Rezultati. Ultrahitro zamrzovanje je dejansko preživelo le 40,2 odst. (51/127) 4-celičnih (p manjše kot 0,001) in kar 78,4 odst. (76/97) 8-celičnih zarodkov (p manjše kot 0,025). Počasno zamrzovanje je bilo uspešno v 76,9 odst. (103/134) 4-celičnih (p manjše kot 0,01) in 72,4 odst. (113/156) 8-celičnih zarodkov (p manjše kot 0,001). Do blastociste so se razvili tudi embrii, ki so imeli po odmrznjenju manj kot polovico intaktnih blastomer. Med tako poškodovanimi embrii je vitalnost ohranilo 47,4 odst. (9/19) ultrahitro zamrznjenih in 44,1 odst. (15/34) počasi zamrznjenih zarodkov. Zaključki. Zgodnji embrionalni stadiji z večjimi blastomerami slabo preživijo ultrahitro zamrzovanje. Pri počasnem zamrzovanju s pomočjo kontroliranega zamrzovalnika velikost blastomer ne vpliva na uspešnost postopka in je zato primernejše za klinično uporabo v humanem materialu.
Descriptors		EMBRYO CRYOPRESERVATION BLASTOCYST ANIMALS, LABORATORY MICE CRYOPROTECTIVE AGENTS BLASTOMERES EMBRYO TRANSFER