Objectives: 

Undernutrition during pregnancy is associated with low birth weight in the offspring and the development of hypertension in adult age, but the mechanisms implicated are not completely understood. Our aim was to assess if maternal undernutrition induces early vascular structural or mechanical alterations in the offspring which might participate in hypertension development later in life.

Materials: 

Rats were fed ad libitum with standard chow throughout gestation or restricted to 50 % from day 10 of gestation until birth. After birth the mother was back to ad libitum diet; the offspring was adjusted to 12 pups (C, control mother pups; R, restricted mother pups) and used at weaning (21 days). The rats were killed by decapitation and the aorta length was measured in situ and after dissection to determine the percentage of retraction. Two segments (3 mm in length) of the thoracic aorta were mounted between two wires in zero-calcium Krebs solution to record isometric tension at increasing levels of stretch (200 microns stretch intervals every 3 min until tissue failure). Segment stiffness was calculated from the slopes of the stretch-tension relationships. A ring section from the thoracic aorta was cut, photographed and diameter and wall thickness was measured with Image J software. Statistical analysis was performed by Student´s t test.

Results: 

Aortic retraction was significantly smaller in R (19.7±0.8) compared to C (22.6±0.9) rats. Isometric tension experiments showed significantly stiffening of the aorta in R group compared to C rats. There was no significant difference between C and R rats in wall thickness or lumen diameter.

Conclusions: 

The offspring of rats exposed to undernutrition during pregnancy exhibit altered passive mechanical properties of the aorta at an early age. These alterations could be related to changes in extracellular matrix content or organization and might contribute to the development of hypertension in the adult age. Supported by Ministerio de Ciencia e Innovación; FEM2009-13434-C02-02).