Liquiritin (LQ) Potentiate Neurite Outgrowth Induced By Nerve Growth Factor In PC12 Cells

Objective:To observe the neuroprotective and neurotrophic effects of liquiritin on PC 12 cells neurite outgrowth induced by nerve growth factor(NGF)Methods:The extension of neurite model was established by NGF in PC12 cells cultured system. The neuroprotective and neurotrophic effects of liquiritin on PC12 cells neurite outgrowth induced by NGF were detected by MTT, LDH, Oligo microarray and RT-PCR analysis.Results:(1)Low dose (5,10,20μg/mL) treatment of liquiritin in the presence of NGF (2 ng/mL) did not affect cellular proliferation of PC 12 cells.However, high dose (50,100 lg/mL) treatment of liquiritin in the presence of NGF (2 ng/mL) significantly decreased cellular proliferation compared to control in the PC 12 cells(P<0.05)(2)Low dose (5,10,20μg/mL) treatment of liquiritin in the presence of NGF (2 ng/mL) did not affect cellular cytotoxin of PC 12 cells.However, high dose (50, 100μg/mL) treatment of liquiritin in the presence of NGF (2 ng/mL) significantly increased cellular cytotoxic in the PC 12 cells(P<0.05)(3)Liquiritin(5-100μg/ml LQ)alone did not trigger differentiation of PC 12 cells. However, Liquiritin(5-100μg/ml LQ)promote neuronal differentiation through NGF dependent manner in the PC12 cells.high dose (50, 100μg/mL) treatment of liquiritin in the presence of NGF (2 ng/mL) significantly increased neuronal differentiation compared to NGF 2 ng/mL alone treatment in the PC 12 cells (P<0.05)(4) Oligo microarray analysis to elucidate the neurotrophic mechanism in the PC 12 cells with liquiritin exposure.Out of the 200 genes covered by the Oligo GEArray Alzheimer's Disease Microarray OHS-057,25 genes were found to be more than twofold upregulated by liquiritin (20μg/mL) treatment after 24 h. Furthermore,5 of 25 up-regulated genes, such as Neurog 3, Nf 1, Notch 2, Nmur 2 and Ntf 5,were highly suggested to play a role in the neuronal differentiation of PC 12 cells after liquiritin exposure.(5)The expressions of Neurog 3,Nf 1, Notch 2, Nmur 2, and Ntf 5 were increased by liquiritin (20μg/mL). The RT-PCR results were consistent with that from the oligo microarray results.Conclusions:(1) Liquiritin promote neuronal differentiation through NGF dependent manner in the PC 12 cells.(2) Liquiritin showed its potential to neurotrophic effects through overexpression of neural related genes such as Neurog 3, Nf 1, Notch 2, Nmur 2 and Ntf 5.