Inhibition by tocopherol of prostaglandin-induced apoptosis in ovine corpora lutea.
Accumulation of toxic oxidants within corpora lutea is a prelude of apoptotic cell death. Vitamin E (alpha-tocopherol) is a biological antioxidant that protects cells from the inductive effects of reactive oxygen on DNA damage and nuclear/cytoplasmic condensation that dictate apoptosis. Ewes were challenged with a luteolytic dose of PGF2 alpha on d 10 of the estrous cycle. The acute decline in circulatory progesterone indicative of the onset of functional luteolysis was not affected by systemic administration of alpha-tocopherol; however, corpora lutea consequently (beyond 24 h) rebounded from the steroidogenic insult. Luteal tissues obtained at 24 h after PGF2 alpha revealed that internucleosomal DNA fragmentation and cellular collapse were inhibited by alpha-tocopherol. These observations indicate that regressive corpora lutea can be spared from terminal involution by diminishing the apoptotic influence of luteolytic hormone with an antioxidant.
Vierk
J E
JE
Department of Animal Science, University of Wyoming, Laramie 82071, USA.
Hansen
T R
TR
Austin
K J
KJ
Van Kirk
E A
EA
Hess
B W
BW
Murdoch
W J
WJ
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001345:Autoradiography; D003338:Corpus Luteum / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D004247:DNA / Q000032:analysis; D015237:Dinoprost / Q000037:antagonists & inhibitors; D005260:Female; D010053:Ovary / Q000502:physiology; D011374:Progesterone / Q000032:analysis / Q000097:blood; D011448:Prostaglandin Antagonists / Q000502:physiology*; D012756:Sheep / Q000502:physiology; D013997:Time Factors; D014018:Tissue Distribution; D014810:Vitamin E / Q000494:pharmacology*