Nitroxide radicals protect cultured rat embryos and yolk sacs from diabetic-induced damage.
BACKGROUND
Diabetic teratogenicity relates, partly, to embryonic oxidative stress and the extent of the embryonic damage can apparently be reduced by antioxidants. We investigated the effects of superoxide dismutase-mimics nitroxides, 2,2,6,6-tetramethyl piperidine-N-oxyl (TPL) as an effective antioxidant, on diabetes-induced embryopathy.


METHODS
Embryos (10.5 day old) and their yolk sacs from Sabra female rats were cultured for 28 h in the absence or in the presence of nitroxides at 0.05-0.4 mM in control, diabetic subteratogenic, or diabetic teratogenic media, and monitored for growth retardation and congenital anomalies. The oxidant/antioxidant status was examined by oxygen radical absorbance capacity and lipid peroxidation assays, whereas the yolk sac function was evaluated by endocytosis assay.


RESULTS
Diabetic culture medium inhibited embryonic and yolk sac growth, induced a high rate of NTDs, reduced yolk sac endocytosis and embryonic antioxidant capacity, and increased lipid peroxidation. These effects were more prominent in the embryos with NTD compared to those without NTD. TPL added to diabetic teratogenic medium improved embryonic and yolk sac growth, reduced the rate of NTDs, and improved yolk sac function. The oxidant/antioxidant status of embryos was also improved. TPL at 1 mM did not damage the embryos cultured in control medium.


CONCLUSIONS
In diabetic culture medium, oxidative damage is higher in the malformed rat embryos compared to those without anomalies; the nitroxide provides protection against diabetes-induced teratogenicity in a dose-dependent manner. The yolk sac damage, apparently caused by the same mechanism, might be an additional contributor to the embryonic damage observed in diabetes.
Ryu
Seonghun
S
Laboratory of Teratology, Department of Anatomy and Cell Biology, Hebrew University-Hadassah Medical School, Jerusalem, Israel 91120.
Kohen
Roni
R
Samuni
Amram
A
Ornoy
Asher
A
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D003497:Cyclic N-Oxides / Q000494:pharmacology*; D016640:Diabetes, Gestational / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D004305:Dose-Response Relationship, Drug; D004578:Electron Spin Resonance Spectroscopy; D046149:Embryo Culture Techniques; D004622:Embryo, Mammalian / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology; D005260:Female; D015227:Lipid Peroxidation / Q000187:drug effects; D009436:Neural Tube Defects / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control; D009589:Nitrogen Oxides / Q000633:toxicity*; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D017382:Reactive Oxygen Species / Q000378:metabolism; D013113:Spin Labels; D015017:Yolk Sac / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology
D000975:Antioxidants; D003497:Cyclic N-Oxides; D009589:Nitrogen Oxides; D017382:Reactive Oxygen Species; D013113:Spin Labels; C039900:nitroxyl; C001803:tempol