摘要：Genipin is an iridoid compound and an aglucon of geniposide isolated from Gardenia fructus . We have previously reported that genipin induces neurite outgrowth in PC12h and Neuro2a cells and protects against cytotoxicity induced by several conditions such as β-amyloid peptide, serum deprivation, and oxidative stress in rat primary hippocampal neurons and Neuro2a cells. In this paper, we examined the protective effect of genipin on A23187 (a calcium ionophore)-induced cytotoxicity in Neuro2a cells. A23187 induced cytotoxicity in concentration- and time-dependent manners as assayed by measurements of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetazolium bromide (MTT) reduction activity and lactate dehydrogenase (LDH) release. The cytotoxicity was significantly suppressed by genipin in a concentration-dependent manner. A23187 also significantly activated caspase3/7, which is known to be the critical mediator of apoptosis, after 1 h, and the cytotoxicity was clearly blocked by an inhibitor of caspase 3/7. Furthermore, A23187 induced the expression of immunoglobulin-binding protein/glucose-regulated protein of 78 kDa (BiP/GRP78) protein, which is an endoplasmic reticulum (ER) stress marker protein, and the expression was suppressed by genipin. These results suggest that genipin protects Neuro2a cells from A23187-induced cytotoxicity mediated by caspase 3/7 and ER stress. Therefore, genipin may be effective in preventing neurodegeneration observed in Alzheimer's disease and Parkinson's disease involving ER stress.
