Protective Effects of Toki-Shakuyaku-San Tsumra Japan-23 (TJ-23) on .BETA.-Amyloid Protein (.BETA.40)-induced Apoptosis in Pheochromocytoma-12 (PC12) Cells

Abstract

The protective effect of a Japanese herbal medicine, Toki-Shakuyaku-San extract (TJ-23) was investigated on β-Amyloid protein (β40)-induced apoptosis in PC12 cells. TJ-23 has been reported to activate cholinergic neurons in the brain, and to aid in the recovery from the spatial cognition disorder induced by scopolamine in rats. The association between neuron death in Alzheimer’s diseas e( AD) and apoptosis has attracted attention, and studies in cultured cells have suggested that β-Amyloid protein induces cell death by apoptosis. The pathway for the induction of apoptosis is caspase cascade activation. In addition, caspase-3 activation due to β-induced injury in PC12 cells has been reported. We evaluated the caspase-3 activity of TJ-23 on β-induced apoptosis in PC12 cells using a fluorophotometer. In our study, TJ-23 significantly inhibited the increase in lactate dehydrogenase (LDH) release following β40-induced cell injury and significantly increased 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction, significantly increasing the cell survival rate. These results suggested the protective effects of TJ-23. In addition, the inhibition of β40-induced cell injury and the significant increase in the cell survival rate by TJ-23 were continuous, suggesting continuous protective effects. TJ-23 significantly inhibited caspase-3 activation due to β40-induced cell injury. These results suggest that a pathway via caspase-3 activation is one of the mechanisms of the protective effects of TJ-23.