0028
STUDY ON
RELATIONSHIP BETWEEN THE FOLATE DEFICIENCY ON WEANLING RAT’S LEARNING AND
MEMORY AND THE HIPPOCAMPAL SYRNAPTOSOMAL MEMBRANE FLUIDITY Department of
Pediatrics, First Affiliated Hospital, Jinan University Medical College, Guangzhou,
China OBJECTIVE: The relationship of hippocampal synaptosomal
membrane fluidity and the alteration of the folate dericiency on weanling
rats’ learning and memory was preliminarily studied .Our research was
expected to provide some zoological evidence to this effect on the aspect
of membrane function. Method: 54 male weanling Sprague-Dawley rats were
divided into three groups .The folate deficient group received an amino
acid-defined diet (RHAA), the ad
libitum control group had the same diet supplemented with folate of 8mg
per kg diet, and the pair-fed control group received the folate
supplemented diet, but was individually pair-fed to the mean daily food
consumption of the folate deficient group. Body weight and food intake were
measured twice weekly. At the end of the second and sixth week of the
experiment, 27 rats, 9 from each group, were undergone a Morris Water Maze
behavioral training for 5 days, an auto-video system recorded the escape
latency and the swimming pattern. The serum folate concentration and the
fluorescence intensity of the hippocampal synaptosomal membrane (r value)
marked by a fluorescent substance DPH, which reflected the membrane
fluidity, were also assayed. Correlation analysis was processed among serum
folate concentration and fluorescence intensity and the percentage of
swimming distance in the platform quadrant. Results: Growth retardation and impaired food intake
associated with FD could not be demonstrated in the FD group rats until the
end of the 3rd week (p<0.05),
while the pair-fed group gradually showed this retardation at the end of
the 4th week .At the end of the experiment the FD rats had
weight loss, leaving the pair-fed group slightly affected (compared with ad libitum control group, p<0.05). Decreased serum folate
occurred at the end of the 2nd week of the experiment, without
alteration of the other parameters. At the end of the 6th week,
FD group rats had very low body weight and serum folate concentration (p<0.01), with the mean escape
latency lengthened and the percentage of swimming distance in the platform
quadrant decreased. The fluorescence intensity of the hippocampal
synaptosomal membrane increased, which implied reduced membrane fluidity (p<0.01). Correlation analysis
results showed that the fluorescence intensity of the hippocampal
synaptosomal membrane(r value)and the serum folate concentration ,mean
escape latency and the percentage of swimming distance in the platform
quadrant were highly correlated(r=-0.527， p
<0.05；r=-0.451， p
<0.05；r=-0.579， p
<0.05). Conclusion: 1. Folate deficiency could impair the
learning and memory of weanling rats and it could reduce weanling rats’
hippocampal synaptosomal membrane fluidity. The impairment was rather
obvious at the 6th week. 2. The reduction of hippocampal synaptosomal
membrane fluidity is possibly one of the mechanisms of folate deficiency
impairing the weanling rats’ learning and memory.
YANG H-M, LING R-Z