Is embryo-cryopreservation really neutral? A new long-term effect of embryo freezing in mice: protection of adults from induced cancer according to strain and sex.
BACKGROUND
Beneficial or harmful effects of embryo freezing have been described in man and animals, raising the question of the neutrality of this technique.


OBJECTIVE
We examined, in mice, the possibility that embryo freezing influences the probability of the emergence, in adults, of an induced urinary bladder cancer.


METHODS
The experiment was conducted in mice derived from embryos of two different genotypes. Females receiving embryos were parsed into two groups according to whether these embryos were cryopreserved or not. The derived adults received the chemical carcinogen N-butyl-N-4hydroxybutylnitrosamine (BBN), in the drinking water. Time to death since the onset of treatment was measured for each animal until the 300th day.


RESULTS
In females from one of the two strains tested, embryo freezing led to a favorable long-term effect on the probability of resistance to induced cancer.


CONCLUSIONS
This beneficial effect, taken together with other effects reported in the literature be they beneficial or harmful, suggests that embryo freezing in mice may not be neutral.
Andrologie et Biologie de la Procréation, CHU de Bicêtre, 94275 Le Kremlin-Bicêtre, France. damien.schoevaert@bct.ap-hop-paris.fr
Maurice
M
Auroux
Italina
I
Cerutti
Béatrice
B
Ducot
Arlette
A
Loeuillet
D000818:Animals; D002273:Carcinogens / Q000633:toxicity; D015925:Cryopreservation; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000378:metabolism / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011247:Pregnancy; D012306:Risk; D012727:Sex Characteristics; D013045:Species Specificity; D016019:Survival Analysis; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced / Q000453:epidemiology / Q000517:prevention & control*
D002273:Carcinogens