Study On The Neuroprotective Effects Of Rice Bran Extracts Rich In γ-aminobutyric Acid

Alzheimer’s s disease(AD)is a neurodegenerative disease of the central nervous system.A number of studies have shown that Amyloid β-protein(Aβ)plays important roles of AD.Rice bran,which is a byproduct of the rice-milling process,contains appreciable quantities of nutrients like proteins,fat,carbohydrates,vitamins and minerals.It also contains bioactive substances like tocopherols,tocotrienols,and y-oryzanol.At present,reports about the neuroprotective effects of rice bran extracts(RBE)can be attributed to presence of tocopherols,tocotrienols,and y-oryzanol.However,there are few reports about rice bran extracts rich in y-aminobutyric acid(GABA).In this study,GABA-rich rice bran and ordinary rice bran were used to prepare the extracts.Then protective effects of GABA-rich RBE on PC 12 cells and primary cultured hippocampal neurons induced AP25-35 were observed.The neuroprotective mechanisms of GABA-rich RBE were explored with compared to the protective effect of RBE from ordinary rice bran.This study includes two parts:The first part is the exploration of the protective effect of GABA-rich RBE on PC 12 cells.PC 12 cells were induced by Aβ25-35 as a cellular model of AD,and they were treated with GABA-rich RBE by means of pre-incubation,co-incubation or incubation after Aβ25-35 treatment,then the protective effects on PC 12 cells were observed.The results showed that three different incubation methods all had protective effects on PC 12 cells,but the concentration of pre-incubation method is lower than that of co-incubation or incubation after Aβ25-35 treatment.The second part is the exploration of the protective effect of GABA-rich RBE on primary cultured hippocampal neurons.Primary cultured hippocampal neurons were induced by Aβ25-35 as a cellular model of AD,and the protective effect and possible mechanism of RBE pretreatment were explored.The results showed that GABA-rich RBE can reduce cell damage,inhibit apoptosis,reduce oxidative stress and improve mitochondrial function,which is better than that of RBE from ordinary rice bran.