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Improved spatial learning and memory by perilla diet is correlated with immunoreactivities to neurofilament and α-synuclein in hilus of dentate gyrus.

Lee J, Park S, Lee JY, Yeo YK, Kim JS, Lim J - Proteome Sci (2012)

Bottom Line: Differential protein expression in the hippocampus was validated by Western blotting using four selected proteins, known to be involved in synaptic plasticity; AMPA receptor, neurofilament, α-synuclein, and β-soluble NSF attachment protein.Brain sections from the perilla-diet groups showed enhanced immunoreactivities to α-synuclein and neurofilament.Especially, neurofilament immunoreactive cells manifested longer neurite projections in the hilus of dentate gyrus of the perilla-diet groups.

View Article: PubMed Central - HTML - PubMed

Affiliation: Major in Food Biomaterials, Kyungpook National University, Daegu, 702-701, South Korea. jkylim@knu.ac.kr.

ABSTRACT

Background: Perilla (Perilla frutescens) oil is very rich in α-linolenic acid, an omega-3 fatty acid. As it is widely reported that omega-3 fatty acid supplementation improves cognitive function in children and adults, feeding rats with perilla diets followed by analysis of proteomic changes in the hippocampus can provide valuable information on the mechanism of learning and memory at the molecular level. To identify proteins playing roles in learning and memory, differentially expressed proteins in the hippocampus of the 5 week old rats fed perilla diets for 3 weeks or 3 months were identified by proteomic analysis and validated by immunological assays.

Results: The perilla diet groups showed improved spatial learning and memory performances in a T-maze test. They also displayed elevated level of 22:6n-3 fatty acid, an omega-3 fatty acid (p<0.05), in the brain compared to the control diet group. Quantitative proteomic analysis using 2-D gels as well as functional annotation grouping with the differentially expressed proteins in the hippocampus showed that those proteins involved in cytoskeleton and transport were the major differentially expressed proteins in the 3-week group, whereas those involved in energy metabolism, neuron projection and apoptosis in addition to cytoskeleton and transport were the major ones in the 3 month group. Differential protein expression in the hippocampus was validated by Western blotting using four selected proteins, known to be involved in synaptic plasticity; AMPA receptor, neurofilament, α-synuclein, and β-soluble NSF attachment protein. Brain sections from the perilla-diet groups showed enhanced immunoreactivities to α-synuclein and neurofilament. Especially, neurofilament immunoreactive cells manifested longer neurite projections in the hilus of dentate gyrus of the perilla-diet groups.

Conclusion: Improved cognitive function upon administration of n-3 fatty acid-rich perilla diet is associated with the differential expression of hippocampal proteins related to cytoskeleton, energy metabolism, transport, neuro-projection, and apoptosis. Particularly, the enhanced immunoreactivities to α-synuclein and neurofilament in the hilus of dentate gyrus suggest that perilla diet supplementation promotes neuronal signaling and alters synaptic plasticity for improved learning and memory.

No MeSH data available.


Related in: MedlinePlus

Immunohistochemical analysis of the dentate gyrus of rats with improved cognitive function fed perilla diets. Representative DAPI-labeled sections containing the dentate gyrus of rats fed perilla (P) or perilla oil (O) diets showed increased immunoreactivities by antibodies against AMPA receptor (A) and α-synuclein (B) compared to control (Cont) diet group. Whereas no significant changes in the density of immunoreactivity was observed in the sections stained by anti-neurofilament antibody (C). However, the immunoreactive cells by anti-neurofilament antibody showed longer neurites (indicated with arrows) in the hilus of dentate gyrus of rats fed perilla- or perilla-oil diets. Scale bars in the first left column represent 100 μm and are the same for other sections. Otherwise, scale bar was designated with a size for higher magnification (last raw in C).
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Figure 4: Immunohistochemical analysis of the dentate gyrus of rats with improved cognitive function fed perilla diets. Representative DAPI-labeled sections containing the dentate gyrus of rats fed perilla (P) or perilla oil (O) diets showed increased immunoreactivities by antibodies against AMPA receptor (A) and α-synuclein (B) compared to control (Cont) diet group. Whereas no significant changes in the density of immunoreactivity was observed in the sections stained by anti-neurofilament antibody (C). However, the immunoreactive cells by anti-neurofilament antibody showed longer neurites (indicated with arrows) in the hilus of dentate gyrus of rats fed perilla- or perilla-oil diets. Scale bars in the first left column represent 100 μm and are the same for other sections. Otherwise, scale bar was designated with a size for higher magnification (last raw in C).

Mentions: As AMPA receptor, neurofilament and α-synuclein were all significantly up-regulated in the hippocampus of rats showing improved spatial learning and memory following perilla-diet intake, we questioned whether or not the up-regulation of protein expression had any histological effects on the hippocampus. To test this, we used primary antibody against AMPA receptor as a positive control for improved learning and memory function along with antibodies against α-synuclein, and neurofilament. We also performed immunohistochemistry staining on the sagittal microtome sections of rat brains (Figure 4). Tissue sections were prepared after completion of the behavioral studies. Anti-AMPA receptor antibody decorated the dentate gyrus of rats with significantly higher intensities following perilla-diet intake for 3 weeks or 3 months (Figure 5A) in comparison with control rats, suggesting that the rats indeed experienced improved spatial cognitive function by perilla-diets. Likewise, antibody against α-synuclein showed higher immunoreactivity in the dentate gyrus of ratsfed perilla- or perilla- oil-diet for 3 weeks or 3 months (Figure 5B). However, no significant differences were observed in the CA1 to 3 regions in the hippocampus or in the cortex (data not shown).


Improved spatial learning and memory by perilla diet is correlated with immunoreactivities to neurofilament and α-synuclein in hilus of dentate gyrus.

Lee J, Park S, Lee JY, Yeo YK, Kim JS, Lim J - Proteome Sci (2012)

Immunohistochemical analysis of the dentate gyrus of rats with improved cognitive function fed perilla diets. Representative DAPI-labeled sections containing the dentate gyrus of rats fed perilla (P) or perilla oil (O) diets showed increased immunoreactivities by antibodies against AMPA receptor (A) and α-synuclein (B) compared to control (Cont) diet group. Whereas no significant changes in the density of immunoreactivity was observed in the sections stained by anti-neurofilament antibody (C). However, the immunoreactive cells by anti-neurofilament antibody showed longer neurites (indicated with arrows) in the hilus of dentate gyrus of rats fed perilla- or perilla-oil diets. Scale bars in the first left column represent 100 μm and are the same for other sections. Otherwise, scale bar was designated with a size for higher magnification (last raw in C).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3539918&req=5

Figure 4: Immunohistochemical analysis of the dentate gyrus of rats with improved cognitive function fed perilla diets. Representative DAPI-labeled sections containing the dentate gyrus of rats fed perilla (P) or perilla oil (O) diets showed increased immunoreactivities by antibodies against AMPA receptor (A) and α-synuclein (B) compared to control (Cont) diet group. Whereas no significant changes in the density of immunoreactivity was observed in the sections stained by anti-neurofilament antibody (C). However, the immunoreactive cells by anti-neurofilament antibody showed longer neurites (indicated with arrows) in the hilus of dentate gyrus of rats fed perilla- or perilla-oil diets. Scale bars in the first left column represent 100 μm and are the same for other sections. Otherwise, scale bar was designated with a size for higher magnification (last raw in C).
Mentions: As AMPA receptor, neurofilament and α-synuclein were all significantly up-regulated in the hippocampus of rats showing improved spatial learning and memory following perilla-diet intake, we questioned whether or not the up-regulation of protein expression had any histological effects on the hippocampus. To test this, we used primary antibody against AMPA receptor as a positive control for improved learning and memory function along with antibodies against α-synuclein, and neurofilament. We also performed immunohistochemistry staining on the sagittal microtome sections of rat brains (Figure 4). Tissue sections were prepared after completion of the behavioral studies. Anti-AMPA receptor antibody decorated the dentate gyrus of rats with significantly higher intensities following perilla-diet intake for 3 weeks or 3 months (Figure 5A) in comparison with control rats, suggesting that the rats indeed experienced improved spatial cognitive function by perilla-diets. Likewise, antibody against α-synuclein showed higher immunoreactivity in the dentate gyrus of ratsfed perilla- or perilla- oil-diet for 3 weeks or 3 months (Figure 5B). However, no significant differences were observed in the CA1 to 3 regions in the hippocampus or in the cortex (data not shown).

Bottom Line: Differential protein expression in the hippocampus was validated by Western blotting using four selected proteins, known to be involved in synaptic plasticity; AMPA receptor, neurofilament, α-synuclein, and β-soluble NSF attachment protein.Brain sections from the perilla-diet groups showed enhanced immunoreactivities to α-synuclein and neurofilament.Especially, neurofilament immunoreactive cells manifested longer neurite projections in the hilus of dentate gyrus of the perilla-diet groups.

View Article: PubMed Central - HTML - PubMed

Affiliation: Major in Food Biomaterials, Kyungpook National University, Daegu, 702-701, South Korea. jkylim@knu.ac.kr.

ABSTRACT

Background: Perilla (Perilla frutescens) oil is very rich in α-linolenic acid, an omega-3 fatty acid. As it is widely reported that omega-3 fatty acid supplementation improves cognitive function in children and adults, feeding rats with perilla diets followed by analysis of proteomic changes in the hippocampus can provide valuable information on the mechanism of learning and memory at the molecular level. To identify proteins playing roles in learning and memory, differentially expressed proteins in the hippocampus of the 5 week old rats fed perilla diets for 3 weeks or 3 months were identified by proteomic analysis and validated by immunological assays.

Results: The perilla diet groups showed improved spatial learning and memory performances in a T-maze test. They also displayed elevated level of 22:6n-3 fatty acid, an omega-3 fatty acid (p<0.05), in the brain compared to the control diet group. Quantitative proteomic analysis using 2-D gels as well as functional annotation grouping with the differentially expressed proteins in the hippocampus showed that those proteins involved in cytoskeleton and transport were the major differentially expressed proteins in the 3-week group, whereas those involved in energy metabolism, neuron projection and apoptosis in addition to cytoskeleton and transport were the major ones in the 3 month group. Differential protein expression in the hippocampus was validated by Western blotting using four selected proteins, known to be involved in synaptic plasticity; AMPA receptor, neurofilament, α-synuclein, and β-soluble NSF attachment protein. Brain sections from the perilla-diet groups showed enhanced immunoreactivities to α-synuclein and neurofilament. Especially, neurofilament immunoreactive cells manifested longer neurite projections in the hilus of dentate gyrus of the perilla-diet groups.

Conclusion: Improved cognitive function upon administration of n-3 fatty acid-rich perilla diet is associated with the differential expression of hippocampal proteins related to cytoskeleton, energy metabolism, transport, neuro-projection, and apoptosis. Particularly, the enhanced immunoreactivities to α-synuclein and neurofilament in the hilus of dentate gyrus suggest that perilla diet supplementation promotes neuronal signaling and alters synaptic plasticity for improved learning and memory.

No MeSH data available.


Related in: MedlinePlus