Protective effects of nourishing spleen yin recipe on endoplasmic reticulum stress-induced neuronal cell damage and its mechanism

Abstract

To determine the protective effects of nourishing spleen yin recipe (Zibu Piyin Recipe, ZBPYR), a compound traditional Chinese herbal medicine, on endoplasmic reticulum (ER) in neuronal cells responding to the stress by using sero-pharmacological method. The mouse neuroblastoma cell line Neuro2a cells were treated with tunicamycin (Tm, an inhibitor of N-glycosylation). The ZBPYR-treated cell group was established by incubating cells with ZBPYR serum for one hour and treated with Tm. Reverse transcriptase PCR (RT-PCR) was utilized to detect the mRNA expressions from two genes after treatments, ER molecular chaperone glucose regulated protein 78 (GRP78) and transcriptional factor CCAAT/ enhancer-binding protein-homologous protein (CHOP). Lactate dehydrogenase (LDH) assay was also carried out to determine the LDH leakage from Neuro2a cells after treated with Tm and staurosporine (STS). The ZBPYR-treated cell group at all tested ZBPYR dosages showed significantly reduced expressions of both genes compared with Tm (5 microg/ml) treated control group (P<0.05). Therefore, ZBPYR serum inhibited the expressions of GRP78 and CHOP in mRNA level under ER stress induced by Tm. Different concentrations of ZBPYR serum pretreatment reduced the LDH leakage compared with the Tm and STS groups (P<0.05). Therefore, ZBPYR serum may inhibit the LDH leakage induced by Tm and STS. ZBPYR has neuroprotective effects. The mechanisms may be associated with inhibition of ER stress and mitochondrial dysfunction.