Histological Study of Lumbosacral Spinal Cord of Mice Embryos who’s Mothers were Administered Retinoic Acid

Abstract

The usefulness of retinoic acid (RA) in reproduction, embryonic and fetal development, growth and tissue maintenance has been established. Excess/low consumption of RA by pregnant rat also leads to congenital malformations affecting the musculoskeletal system and nervous system.

The aim of this study was to investigate the histological changes of the lumbosacral spinal cord in mice embryos whose mothers were administered RA on day 8 post coitum (dpc). Twenty pregnant albino mice were divided into two groups of 10 each. The experimental group received a single dose (70mg/kg) of RA dissolved in vegetable oil by gastrointestinal route, delivered by gavage on gestational day 8, while the control group received only vegetable oil by the same route on gestational day 8. The animals were all sacrificed on gestational day 14 and their embryos harvested and studied. Gross malformations were observed around the lumbosacral region. Microscopic observations revealed reduction in left and right anterior horn thickness (diameter) of the lumbosacral spinal cord region of experimental group (0.01885mm ± 0.00045mm and 0.01872mm ± 0.00054mm) against control (0.02015mm ± 0.00065mm and 0.02002mm ± 0.00054mm) P<0.05. Quantification of left and right lumbosacral anterior horn cell density revealed reduction in cell density of experimental group (354.4 ±4.77493 and 351.6 ± 6.542) P<0.05 against control (366.0 ± 6.245 and 366.4 ± 7.056). This study showed that one dose of 70mg/kg RA administered through the gastrointestinal route by gavage to pregnant mice on 8dpc caused neural tube defect such as spina bifida occluta, reduction in embryonic neural cell proliferation, reduction of lumbosacral anterior grey horn density and thickness.

Key Words: Administration, Embryonic, Gestational, Malformation, Spina bifida.