Differential effects of chronic iron deficiency anaemia on junctional and labyrinthine zones of placenta in Sprague dawely rat

Abstract

Iron deficiency anaemia causes adverse pregnancy outcome. Studies reveal its generalized effects on histomorphometry of the placenta, without details on specific zones nor effect of gestational age. These data are important for planning  intervention. This study was, therefore, designed to describe the histomorphometric changes associated with iron deficiency anaemia on placenta of albino rat. Fourty nine (49) Sprague – Dawely albino rats were randomly separated into experimental and control groups. The  experimental group was rendered anaemic by removing 1.5 ml of blood per bleed on five alternate days. Placentas were collected on gestational days 17, 19 and 21. Five cubic milimetre segments were fixed in 10 % buffered formaldehyde solution; dehydrated in ethanol and embedded in paraffin wax. Five micron thick sections were cut, deparaffinized and stained with Hematoxylin and Eosin. Micrographs were taken using Leica ICC 50 digital photomicrographic camera attached to a computer at magnification x40 and the thickness of the labyrinth and junctional zones measured. Student t- test was used to compare values for the   experimental and control groups. The labyrinth in the chronic anaemia group was thinner than in the control group at gestational days 17, 19 and 21. The junctional zone, on the other hand, was consistently thicker in anaemic than in the control animals. The difference in thickness of junctional zone varied with  gestational age. At gestational day 17, the zone was significantly thicker in the anaemic group (628.9 μ) than in the control (381 μ). On day 19 and 21, however, the difference was not statistically  significant. In conclusion, the effects of chronic iron deficiency anaemia on the labyrinth differ from those on the junctional zone of the placenta. This differential effect appears to depend on the function and gestational age. The decrease in thickness of the  labyrinth may be designed to maintain placental diffusion capacity while increased thickness of the junctional zone constitutes a compensatory physical and nutritional adaptation to hypoxia.

Key words: placenta, labyrinthine, junctional zones, thickness, anaemia.