Pathogenesis of Pregnancy-Induced Hypertensive Disorders A Review of Experimental Animal Models

Stress in pregnancy: a new Wistar rat model for human preeclampsia

OBJECTIVE

Our study evaluated the effects of chronic and/or acute stress on pregnant and nonpregnant female rats.

STUDY DESIGN

The rats were exposed to the sonic stimulus associated with overpopulation between days 7 and 14 of pregnancy. The rats were immobilized 2 days before the vascular reactivity experiments.

RESULTS

In 14-day pregnant rats, chronic stress led to lower weight, increased adrenal weight, lower endothelium-derived relaxing factor release, and lower fetal weight. In 20-day pregnant rats, chronic stress caused decreased weight gain, higher blood pressure, increased vasomotility and proteinuria, lower endothelium-derived relaxing factor release, and lower fetal weight. In the 20-day pregnant group, the higher adrenal weight resulted in higher blood pressure, lower vascular relaxation, and lower average fetal weight. A greater number of fetuses had higher adrenal weight, higher blood pressure, and lower vascular relaxation.

CONCLUSION

The alterations found in the rats were similar to those that occur in human preeclampsia. Therefore, we propose a new animal model for human preeclampsia.

Animal models of preeclampsia

Some of the maternal symptoms of preeclampsia can be produced by uterine ischemia, although no quadriped spontaneously exhibits this disease. It may be that the combination of upright posture and uteroplacental ischemia are necessary for manifestation of the full syndrome. Chronic nitric oxide synthase inhibition in rats produces a pattern of change that resembles the symptoms of preeclampsia, and the preeclamptic-like response of rats with adriamycin nephropathy and hyperinsulinemia is associated with endothelial dysfunction. These models are definitely of use in preeclampsia research, but because this disease only occurs spontaneously in primates, the definitive studies on preeclampsia will, of necessity, be clinical.