Effect of in ovo feeding of folic acid on Disabled-1 and gga-miR-182-5p expression in the cerebral cortex of chick embryo.

Folate (vitamin B9) has been shown to reduce the prevalence of neural tube defects (NTDs). Many genes comprising Disabled-1 (DAB1) and miRNAs have been shown to play important role in normal brain development. Reelin-signalling has been shown to play key role in regulating of neuronal migration during brain development. The aim of this study was to evaluate the effects of in ovo administration of folic acid (FA) on DAB1 and gga-miR-182-5p expression in the cerebral cortex of chick embryo. A total number of 30 hatching eggs were used in this study. The number of 10 eggs were injected into the yolk sac with FA (150 µg/egg), 10 eggs by normal saline (sham group) on embryonic day 11 and 10 eggs were left without injection as control. Then the cerebral cortices were collected on E19 and the expression of DAB1 and gga-miR-182-5p was studied by Real-Time PCR. The results showed that DAB1 expression in the cerebral cortex of FA-treated, sham and control were 2.51 ± 0.13, 1.01 ± 0.04 and 1.03 ± 0.04 fold changes, respectively, and this amount for gga-miR-182-5p were 0.54 ± 0.03, 1.09 ± 0.07 and 1.00 ± 0.06-fold change respectively. Statistical analysis showed that there is a significant increase in DAB1 and a decrease in gga-miR-182-5p expression in FA injected cerebral cortex as compared either with either SHAM or control (p < 0.0001). But, no significant change in DAB1 and gga-miR-182-5p expression was observed between sham and the control group (p = 0.99 and p = 0.57 respectively). It is concluded that in ovo feeding of FA increases DAB1 and decreases gga-miR-182-5p expression in the developing chick cerebral cortex.