Late-gestation ventricular myocardial reduction in fetuses of hyperglycemic CD1 mice is associated with increased apoptosis.
BACKGROUND
Previous work in our laboratory showed reduced myocardium and dilated ventricular chambers in gestation day (GD) 17 hearts that were collected from hyperglycemic CD1 mouse dams. Pre-breeding maternal immune stimulation, using Freund's complete adjuvant (FCA), diminished the severity of these fetal heart lesions. The following experiments were performed to detect possible changes in fetal heart apoptotic cell death, under hyperglycemic conditions and with or without maternal immune stimulation.


METHODS
Female CD1 mice were injected with 200 mg/kg of streptozocin (STZ) to induce insulin-dependent diabetes mellitus. Half of these mice received prior FCA injection. Fetal hearts were collected on GD 17 and myocardial apoptotic cells were quantified using flow cytometry. A panel of apoptosis regulatory genes (Bcl2, p53, Casp3, Casp9, PkCe) was then examined in the fetal myocardium using RT-PCR.


RESULTS
Early apoptotic cells and late apoptotic/necrotic cells were significantly increased in fetal hearts from STZ or STZ+FCA dams. Pre-treatment with FCA reduced late apoptotic/necrotic cells to control level, suggesting some cell death protection was rendered by FCA. Paradoxically in the face of such increased cell death, the expression of pro-apoptotic genes Casp3 and Casp9 was decreased by diabetes, while the anti-apoptotic gene Bcl2 was increased.


CONCLUSIONS
Maternal hyperglycemia causes dys-regulated apoptosis of fetal myocardial cells. Such effect may be prevented by maternal immune stimulation.
Gutierrez
J Claudio
JC
Instituto de Farmacología y Morfofisiología, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Casilla, Chile. jcgutierrez@docentes.uach.cl
Prater
M Renee
MR
Smith
Bonnie J
BJ
Freeman
Larry E
LE
Mallela
Murali K
MK
Holladay
Steven D
SD
D000818:Animals; D017209:Apoptosis; D001786:Blood Glucose / Q000032:analysis; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000276:immunology / Q000473:pathology*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000276:immunology / Q000473:pathology*; D005260:Female; D005434:Flow Cytometry; D005620:Freund's Adjuvant / Q000494:pharmacology; D020869:Gene Expression Profiling; D005865:Gestational Age; D006330:Heart Defects, Congenital / Q000139:chemically induced / Q000276:immunology / Q000473:pathology*; D006352:Heart Ventricles / Q000187:drug effects / Q000276:immunology / Q000473:pathology*; D006943:Hyperglycemia / Q000139:chemically induced / Q000276:immunology / Q000473:pathology; D008297:Male; D008431:Maternal-Fetal Exchange; D051379:Mice; D008815:Mice, Inbred Strains; D009206:Myocardium / Q000276:immunology / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000097:blood / Q000276:immunology / Q000473:pathology*
D001786:Blood Glucose; D005620:Freund's Adjuvant