RESUMO
<p><b>OBJECTIVE</b>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).</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>Gen and/or FA could protect the neuronal and mitochondrial membrane from the impairment induced by Aβ31-35.</p>