The effect of dietary n‐3 fatty acid deficiency on BDNF expression and spatial learning behavior in rats

Abstract

A growing body of literature indicates that brain derived neurotrophic factor (BDNF) plays an important role in brain development, particularly in learning and memory function. Essential fatty acids are critical nutrients involved in brain development. To investigate the effects of dietary n-3 fatty acid deficiency on brain BDNF expression and its relationship with learning and memory, Sprague Dawley rats were maintained on a semi-purified diet with adequate or deficient n-3 fatty acids for generations. At the third generation, ten pups at four weeks of age from each group were tested for their spatial learning ability using Morris water maze (MWM) test. At the end of the behavioral test, animals were sacrificed and the brain tissues were assayed for BDNF protein and mRNA levels using ELISA and real-time PCR techniques. Compared with the control animals, the levels of BDNF mRNA in the cerebral cortex and the hippocampus were significantly lower (p<0.05) in n-3 fatty acid deficient pups, although the levels of BDNF proteins in the same regions did not significantly differ. During the learning phase, pups from the deficient group performed significantly poorer in MWM test in comparison to the controls (p<0.05), while the long term memory was not affected by the diet. The results of this study indicate that n-3 fatty acid deficiency affects BDNF expression in the brain, and it also impairs the spatial learning and memory ability. The study was partially supported by Hong Kong Research Grants Council.