The protective effect and mechanism of "Kai Xing San" on damaged SH-N-K neural cells induced by Aβ_(25-35)

Objective To investigate the protective effect of Kai Xin San(KXS) on SH-N-K neural cells induced by neurotoxic amyloid peptide(Aβ_(25-35)).Methods Treated human neuroblastoma SK-N-SH cells with Aβ_(25-35),simulating the pathologic damage in brain of patients with Alzheimer's disease,and antagonized the effect by adding KXS.Cell survival rate and apoptosis rate were measured by MTT assay and flow cytometry,intracellular superoxide dismutase(SOD) level were tested by enzymatic method.The expression of amyloid precursor protein(APP) gene and Aβ degradating enzyme neprilysin(NEP) gene were detected by RT-PCR and APP protein expression detected by Western-blotting.Results The experiment showed that survival ratio of SK-N-SH cells were significantly decreased after exposure on Aβ_(25-35),and the treatment of KXS significantly increased survival ratio and decreased apoptosis ratio of Aβ damaged SK-N-SH cells and increased cellular SOD activity(P0.01).RT-PCR result indicated that the KXS might related to the Aβ metabolism gene,decreased APP gene expression and APP protein expression and improved NEP gene expression significantly.Conclusion Aβ_(25-35),related to the pathology of Alzheimer's disease,can result in the damage and death of neuron cells,and KXS may exert neuroprotective effect on SH-N-K neural cells induced by neurotoxic Aβ which might associated with that KXS can increase SOD activity,and upregulate APP and downregulate NEP gene expression,so decrease Aβ production,then inhibit cell death.