High dose cotinine may induce neural tube defects in a chick embryo model.
OBJECTIVE
Nicotine is a well-known agent among 4000 chemicals in cigarettes. About 70 to 80% of nicotine is converted to cotinine, a major metabolite. The aim of the present study is to investigate the effect of cotinine on neural tube development in a chick embryo model.


METHODS
Sixty fertile, specific pathogen free eggs were divided into 6 groups for this study. In the first group, a fixed cotinine concentration for each egg was calculated just to simulate the concentration of a smoker's blood level. A second experimental group was designed at a higher cotinine concentration. Embryos that succeeded to reach Hamburger-Hamilton stage 12 from each group were then embedded into paraffin for permanent sections. These two groups were compared with eggs subjected to vehicle (standard alcohol and ten times more alcohol concentration) and control groups (saline and sham groups).


RESULTS
Embryos of the cotinine (regular dose), vehicle and control groups were normal, but embryos subjected to higher cotinine concentrations were malformed at the cranial part of the thoracic neural tube.


CONCLUSIONS
Association of cotinine with neural tube defects was demonstrated in the present study. Cigarette smoking may induce hazardous effects on neural tube development.
Dalgiç
Ali
A
Ankara Numune Educational and Research Hospital, II. Neurosurgery Clinic, Ankara, Turkey. alidalgic@yahoo.com
Armağan
Ercan
E
Helvacioğlu
Fatma
F
Okay
Onder
O
Dağlioğlu
Ergun
E
Take
Gülnur
G
Unlü
Ağahan
A
Belen
Deniz
D
D000818:Animals; D002642:Chick Embryo; D002645:Chickens; D003367:Cotinine / Q000633:toxicity*; D004195:Disease Models, Animal; D004475:Ectoderm / Q000002:abnormalities / Q000187:drug effects / Q000473:pathology; D007202:Indicators and Reagents / Q000633:toxicity*; D007267:Injections / Q000379:methods; D054259:Neural Tube / Q000002:abnormalities / Q000187:drug effects / Q000473:pathology; D009436:Neural Tube Defects / Q000139:chemically induced* / Q000473:pathology
D007202:Indicators and Reagents; D003367:Cotinine