Turkish Neurosurgery 2022 , Vol 32 , Num 3
Effects of Dexamethasone Exposure on Neural Crest Cells and Primary and Secondary Neurulation in Chick Embryos
1Istanbul Medeniyet University, Department of Histology and Embryology, Istanbul, Turkey
2Haydarpasa Numune Training and Research Hospital, Department of Neurosurgery, Istanbul, Turkey
3Acibadem Mehmet Ali Aydinlar University, Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Istanbul, Turkey
4Ege University, Department of Histology and Embryology, Izmir, Turkey
5Kartal Kosuyolu High Specialization Training and Research Hospital, Department of Anesthesiology and Reanimation, Istanbul, Turkey
DOI : 10.5137/1019-5149.JTN.34904-21.2 AIM: To evaluate the effects of dexamethasone (Dex) treatment on neural crest cells and primary and secondary neurulation in chick embryos.

MATERIAL and METHODS: Sixty fertilized eggs with an average weight of 65 ± 2 g were incubated in 60%?70% humidity at 37.2°C ± 0.1°C. After 26 hours of incubation, the control group (n=12) received 0.1 mg/kg physiologic saline (S), group 1 (n=12) received 0.1 mg/kg Dex, group 2 (n=12) received 1 mg/kg Dex, and group 3 (n=12) received 5 mg/kg Dex into each embryonic disc. The eggs were incubated until Hamburger?Hamilton stage (HH) 15, HH18, and HH20. Then, the embryos were dissected and evaluated both macroscopically and microscopically.

RESULTS: The mortality rate in the control group, group 1, and groups 2 and 3 was 27%, 48%, and 100%, respectively. The neural tube thicknesses in group 1 significantly increased in HH 15 and HH20 (p<0.05). The mitosis number in group 1 significantly decreased in each stage (p<0.05). Wnt-1 expression was significantly lower in group 1 in HH15 (p<0.05) and HH18 (p<0.05), but there was no significant difference in HH20 (p>0.05). Fibroblast growth factor (FGF) expression was significantly lower in group 1 in HH15 (p<0.05). The expression of N-cadherin was significantly higher in group 1 in HH20 (p<0.05). Fibronectin expression decreased in group 1 in HH18 (p<0.01).

CONCLUSION: Although the Dex treatment did not result in neural tube closure defect, the mortality rates and neural tube thicknesses increased, whereas mitotic activation and Wnt-1 and FGF signal pathways reduced in some stages. Keywords : Primary neurulation, Secondary neurulation, Neural crest cells, Dexamethasone, Chick embryo

Corresponding author : Nuray ALACA, nuray.alaca@acibadem.edu.tr