Developmental indices of nutritionally induced placental growth restriction in the adolescent sheep.
Most intrauterine growth restriction cases are associated with reduced placental growth. Overfeeding adolescent ewes undergoing singleton pregnancies restricts placental growth and reduces lamb birth weight. We used this sheep model of adolescent pregnancy to investigate whether placental growth restriction is associated with altered placental cell proliferation and/or apoptosis at d 81 of pregnancy, equivalent to the apex in placental growth. Adolescent ewes with singleton pregnancies were offered a high or moderate level of a complete diet designed to induce restricted or normal placental size at term, respectively. Bromodeoxyuridine (Brd-U) was administered to H and M ewes 1 h before slaughter. Placental tissues were examined for a) Brd-U (immunohistochemistry) and b) apoptosis regulatory genes by in situ hybridization, Northern analyses (bax, mcl-1), immunohistochemistry, and Western analyses (bax). Quantification was carried out by image analysis. Total placentome weights were equivalent between groups. Brd-U predominantly localized to the trophectoderm and was significantly lower in the H group. Bax and mcl-1 mRNA were localized to the maternal-fetal interface. Bax protein was significantly increased in the H group and predominant in the uninuclear fetal trophectoderm. These observations indicate that reduced placental size at term may be due to reduced placental cell proliferation and possibly increased apoptosis occurring much earlier in gestation.
Lea
Richard G
RG
Ovine Pregnancy Group, Rowett Research Institute, Bucksburn, Aberdeen, Scotland. R.Lea@rri.sari.ac.uk
Hannah
Lisa T
LT
Redmer
Dale A
DA
Aitken
Raymond P
RP
Milne
John S
JS
Fowler
Paul A
PA
Murray
Joanne F
JF
Wallace
Jacqueline M
JM
D000293:Adolescent / Q000502:physiology*; D000818:Animals; D005260:Female; D005317:Fetal Growth Retardation; D005333:Fetus / Q000033:anatomy & histology; D005865:Gestational Age; D006801:Humans; D008423:Maternal Age; D039382:Maternal Nutritional Physiological Phenomena; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D010920:Placenta / Q000166:cytology / Q000378:metabolism; D010929:Placentation; D011247:Pregnancy; D011270:Pregnancy, Animal; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034561:Sheep, Domestic; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D051028:bcl-2-Associated X Protein