[Effects of genistein and folic acid on neuronal membrane and mitochondrial membrane damaged by β-amyloid peptides 31-35].
OBJECTIVE
To observe the neuro-protective effects of genistein (Gen) and folic acid (FA) on neurons membrane and mitochondrial membrane damaged by β-amyloid peptides 31-35 (Aβ31-35).


METHODS
The primary cultured rat cerebral cortical neurons were randomly divided into DMEM (control), Aβ31-35 (25 µmol/L), Gen (Gen 27 µg/ml), FA (FA 40 µg/ml) and Gen + FA (Gen 27 µg/ml + FA 40 µg/ml). Gen and/or FA were added two hours before Aβ31-35 addition. After twenty four hours, MTT assay was performed to measure the viability of cultured neurons. Fluorescence polarization was performed to observe the neuron cell membrane fluidity. The mitochondrial membrane potential (MMP) was determined to investigate the alteration of mitochondrial structure and function of neurons by laser scanning confocal microscope and a flow cytometer was used to investigate the activation of mitochondrial permeability transition pore (MPTP). Each experiment was repeated three times.


RESULTS
Compared with group Aβ31-35 (0.845 ± 0.050, F = 4.931, P < 0.05), the absorbance was significantly higher in group Gen (0.982 ± 0.110, t = 3.523, P < 0.01), FA (0.947 ± 0.061, t = 2.745, P < 0.01) and Gen + FA (0.996 ± 0.090, t = 3.966, P < 0.01). The viscosity of cell neuron membrane in group Gen (1.75 ± 0.28, t = 2.085, P < 0.05), FA (1.66 ± 0.37, t = 2.357, P < 0.05) and Gen + FA (1.50 ± 0.20, t = 3.784, P < 0.05) was significantly lower than that in group Aβ31-35 (2.11 ± 0.44, F = 5.529, P < 0.01), which indicated the cell membrane fluidity was significantly higher in group Gen and/or FA than that in group Aβ31-35. MMP was significantly decreased by Aβ31-35 (3.364 ± 1.140, t = 3.949, P < 0.01) when comparing to control group (6.383 ± 1.683), while it was significantly increased by Gen (5.286 ± 1.792, t = 2.406, P < 0.05), FA (5.884 ± 2.022, t = 2.887, P < 0.01) and Gen + FA (6.120 ± 2.124, t = 3.304, P < 0.01) when comparing to group Aβ31-35 (F = 7.585, P < 0.01). MPTP was activated by Aβ31-35 and Gen and/or FA could reverse this progress.


CONCLUSIONS
Gen and/or FA could protect the neuronal and mitochondrial membrane from the impairment induced by Aβ31-35.
School of Public Health and Family Medicine, Capital Medical University, Beijing 100069, China.
Huan-ling
HL
Yu
Xiao-hong
XH
Zhang
Rong
R
Xiao
Li
L
Li
Li
L
Xiang
Jin-fang
JF
Feng
Lin-hong
LH
Yuan
Wei-wei
WW
Ma
D016229:Amyloid beta-Peptides / Q000009:adverse effects; D000818:Animals; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects; D005492:Folic Acid / Q000494:pharmacology*; D019833:Genistein / Q000494:pharmacology*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010446:Peptide Fragments / Q000009:adverse effects; D051381:Rats; D017208:Rats, Wistar
D016229:Amyloid beta-Peptides; D018696:Neuroprotective Agents; D010446:Peptide Fragments; C113042:amyloid beta-protein (31-35); D005492:Folic Acid; D019833:Genistein