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EFFECTS OF VITAMIN A DEFICIENCY ON EMBRYONIC BRAIN DEVELOPMENT IN RATS

Chen LN, Li TY & Qu P

Children’s Hospital, Chongqing University of Medical Sciences, Chongqing, China

Objective: To study the effect of vitamin A deficiency (VAD) on embryonic brain development in rats and it’s mechanisms in molecualar biology.

Methods: 9 female Wistar rats were randomly divided into severe VAD (SVAD), marginal VAD (MVAD) and Control groups. The rats were fed with vitamin A (VA) O IU/kg, 400 IU/kg and 6500 IU/kg diets respectively starting from 3 weeks before pregnancy onwards. Body weight, brain weight, serum VA level, brain VA content and protein content, brain cell proliferative cycle and the expression of RAR_α, RAR_β,RXR_β and D₂R Mrna were measured at birth.

Results: (1) There were significant differences in VA level in serum and brain tissue between groups. (2) The body and brain weights in SVAD group were lighter than those in both MVAD and Control group. (3) The brain protein content in SVAD group was significant lower than that of Control group. (4) The cell proliferative index (PI) in SVAD group was significantly lower than that of Control group. (5) The expression of RAR _α, RAR_β,RXR_{β ,} RXR_β and D₂R mRNA in SVAD group and MVAD group were lower than those of Control group.

Conclusion: (1) VAD can decrease brain VA content and affect embryonic brain development. (2) Brain development defects in embryonic VAD rats including brain weight loss, decrease of brain protein content, and brain cell proliferation inactive. (3) The embryonic brain development defects may be related with the decreased expression of RAR_α, RAR_β, RXR_{β ,} and D₂R in brain cell.