Ninjin-yoei-to, a Kampo medicine, prevents hippocampal neurodegeneration by amyloid β_1-42-induced Zn²⁺ toxicity

Abstract

We examined the preventive effect of Ninjin-yoei-to (NYT) on amyloid β_1-42 (Aβ_1-42)-induced hippocampal neuron death in vivo. Pre-administration of NYT for 2 weeks prevented Aβ_1-42-induced neuron death. Aβ_1-42-induced increase in intracellular Zn²⁺ in dentate granule cells was blocked by NYT intake for 2 weeks. The present study suggests that pre-administration of NYT prevents neuron death in the hippocampus by blocking Aβ_1-42-induced intracellular Zn²⁺ toxicity via induction of metallothioneins, intracellular Zn²⁺-binding proteins. NYT may be effective for preventing Alzheimer’s disease.