EFFECT OF PRENATAL PHENYTOIN EXPOSURE ON THE APICAL ECTODERMAL RIDGES OF CHICK WING BUDS

Prenatal Phenytoin Exposure And The Apical Ectodermal Ridges

Abstract

Objective: To observe the effect of sodium phenytoin on the development of the apical ectodermal ridges (AER) in chick wing buds.
Study Design: Laboratory based case-control study.
Place and Duration of Study: This study was carried out at the Department of Anatomy located at the Regional Center of College of Physicians and Surgeons Islamabad Pakistan, from Jan 2014 to Jan 2015.
Material and Methods: Sixty fertilized chicken eggs of ‘Egyptian fayoumi’ breed were selected and divided into two subgroups, experimental and control, each having 30 eggs. A single dose of 3.5 mg sodium phenytoin was injected in each egg of the experimental subgroup while controls were administered same volume of normal saline. The embryos were extracted 96 hours (day 4) after incubation. Histological sections were cut at 5 μm thickness and stained with Feulgen Nuclear and Light Green to measure the maximum thickness of the apical ectodermal ridges. The number of cells and mitoses in each ridges were also counted. SPSS 16 was used for statistical analysis.
Results: There was no significant difference between experimental and control subgroups regarding the maximum thickness and number of cells in the apical ectodermal ridge but there was a statistically significant reduction in the number of mitoses in the experimental ridges.
Conclusion: The study shows that sodium phenytoin exerts an inhibitory effect on the apical ectodermal ridges of developing limbs evident by the decreased number of mitoses in the AER of wing buds of experimental chick embryos making it a potential target site for limb teratogenicity associated with its maternal intake during pregnancy.