Effects Of Vitamin A
Deficiency On Brain Development, Learning And Memory In Young Rats
Li TY, Chen LN
& Qu P
Children’s Hospital,
Chongqing University of Medical Science, Chongqing, China
Objective: To study the effects of
vitamin A deficiency (VAD) on brain development, learning and memory
ability in young rats and it’s mechanisms in molecular biology.
Methods: 6 female Wistar rats
were randomly divided into VAD and Control group, and were fed with VA 400
IU/kg and 6500 IU/kg diets from the beginning of pregnancy until young rats
aged 7 weeks old, respectively. Growth and development, learning and memory
ability, VA level in serum and brain, protein content in brain, cell
proliferative cycle of cortex and hippocampus, hippocampus cell ultrastructure
changes in electron microscopy of rats and the expression of RARα, RARβ, RXRβand D2R mRNA
in brain cell were detected.
Results: (1) The weight increase
of VAD group rats was slower than those rats in Control group. (2) Learning
and remember scores of VAD rats were significant lower than those of
Control group. (3) The protein contents of cortex and hippocampus in VAD
group were significant lower than those of Control group. (4) The
proliferative indices of cortex and hippocampus in VAD group were higher
than those of Control group. (5) The synapses between hippocampus pyramidal
cells in VAD group were significantly decreased and the small bubbles in
synapses were also decreased. The astrocytes in hippocampus in VAD group
were significantly increased. Degeneration was observed in many astrocytes.
(6) The expression of RARα, RARβ, RXRβand D2R mRNA in VAD group were lower
than those of Control group.
Conclusion: (1) VAD can affect
brain development and the ability of leaning and memory in young rats. (2)
Brain developmental defects in VAD rats included lower brain protein content
and hippocampus cell ultrastructure changes. (3) The brain development,
learning and memory defects may be due to decreased expression of RARα, RARβ, RXRβ, D2R in
brain cell.