Vascular anomalies of mouse fetuses exposed to anoxia during pregnancy

Prenatal immune challenge alters the hypothalamic-pituitary-adrenocortical axis in adult rats

We investigated whether non-abortive maternal infections would compromise fetal brain development and alter hypothalamic-pituitary-adrenocortical (HPA) axis functioning when adult. To study putative teratogenic effects of a T cell-mediated immune response versus an endotoxic challenge, 10-d-pregnant rats received a single intraperitoneal injection of 5 x 10(8) human red blood cells (HRBC) or gram-negative bacterial endotoxin (Escherichia coli LPS: 30 micrograms/kg). The adult male progeny (3 mo old) of both experimental groups showed increased basal plasma corticosterone levels. In addition, after novelty stress the HRBC group, but not the LPS group, showed increased ACTH and corticosterone levels. Both groups showed substantial decreases in mineralocorticoid (MR) and glucocorticoid receptor (GR) levels in the hippocampus, a limbic brain structure critical for HPA axis regulation, whereas GR concentrations in the hypothalamus were unchanged and in anterior pituitary were slightly increased. HRBC and LPS indeed stimulated the maternal immune system as revealed by specific anti-HRBC antibody production and enhanced IL-1 beta mRNA expression in splenocytes, respectively. This study demonstrates that a T cell-mediated immune response as well as an endotoxic challenge during pregnancy can induce anomalies in HPA axis function in adulthood. Clinically, it may be postulated that disturbed fetal brain development due to prenatal immune challenge increases the vulnerability to develop mental illness involving inadequate responses to stress.

Simultaneous prevention of blood abnormalities and hereditary congenital amputations in a brachydactylous rabbit stock

Hematological and histological studies of the rabbit brachydactyly mutant were made to clarify the question of the blood abnormality that had previously been implicated in the teratogenic process leading to congenital amputation. The hemoglobin of fetal and adult br/br rabbits, studied by electrophoresis and cyanmethemoglobin assay, exhibited no differences from that of controls. The br/br fetuses were polycythemic and severely macrocytic. Fetal limb vessels showed thrombosis leading to hemorrhages in the extremities. The hepatic tissue was abnormal, being particularly poor in hematopoietic cells; blood cell macrocytosis was attributed to impaired erthropoiesis. Treatment of pregnant rabbits with folic acid plus vitamin B12 or with folinic acid was able simultaneously to prevent the fetal blood cell macrocytosis and the congenital abnormalities.

Maternal endotoxemia, fetal anomalies, and central nervous system damage: a rat model of a human problem

Endotoxemia is a common consequence of the gram-negative urinary tract infections that complicate human pregnancies. Only rarely, however, have the effects of maternal endotoxemia been evaluated by animal experiments or by human investigations. Data of the Collaborative Perinatal Study suggest an association between maternal endotoxemia and fetal central nervous system damage. For these reasons we performed controlled studies of the fetal effects of treatment of pregnant rats, at appropriate gestational ages, with E. coli endotoxin. We found a maximum 7 per cent incidence of fetal anomalies in the treated animals but no anomalies in controls. Placental light microscopy examinations indicated the mechanism to include Shwartzman-lixemia produces periventricular leukomalacia. We obtained an incidence of neuronal necrosis in treated fetuses that was 10 times greater than in control fetuses. It is therefore of importance that additional studies of the pathologic effects of endotoxin be performed.

Cardiac malformations in the rat induced by maternal hypercapnia with hypoxia

Forty-seven pregnant rats were exposed for 24 hours to a gas mixture of 6% carbon dioxide, 10% oxygen and 84% nitrogen on different days during gestation. The earliest exposure was on the fifth day after observed copulation, the latest on the sixteenth. The hearts of 370 newborn test rats were studied in serial sections and compared with those from 111 newborn control rats. The over-all incidence of cardiac malformations was 28.1% in the experimental animals and 4.5 % in the controls. In the test groups, severe structural anomalies resulted from exposures as early as the fifth day of gestation.

The results of the present and of previous experiments suggest that maternal hypercapnia in the presence of normal and low oxygen tensions is markedly teratogenic for the cardiovascular system in the rat.

Lactic Acid Accumulation as a Cause of Hypoxia-Induced Malformations in the Chick Embryo

Most hypoxia-induced malformations are caused by a syndrome involving tremendous edema followed by formation of clear blisters and hematomas. These, in turn, mechanically interfere with development. Studies of blood pH and lactic acid indicate that lactate accumulation initiates this syndrome. The effects of lactic acid injections parallel those of subjection to hypoxia, confirming this conclusion.