Aloperine (ALO), one of the alkaloids isolated from Sophora alopecuroides L., is traditionally used for various diseases including neuronal disorders. This study investigated the protective effects of ALO on neonatal rat primary-cultured hippocampal neurons injured by oxygen-glucose deprivation and reperfusion (OGD/RP). Treatment with ALO (25, 50, and 100 mg/l) attenuated neuronal damage (p < 0.01), with evidence of increased cell viability (p < 0.01) and decreased cell morphologic impairment. Furthermore, ALO increased mitochondrial membrane potential (p < 0.01), but inhibited intracellular-free calcium [Ca(2+)] i (p < 0.01) elevation in a dose-dependent manner at OGD/RP. ALO also reduced the intracellular reactive oxygen species and malondialdehyde production and enhanced the antioxidant enzymatic activities of catalase, superoxide dismutase, glutathione peroxidase and the total antioxidant capacity. The results suggested that ALO has significant neuroprotective effects that can be attributed to anti-oxidative stress.

No abstract

Oxysophocarpine (OSC), an alkaloid isolated from Sophora flavescens Ait, has been traditionally used as a medicinal agent based on the observed pharmacological effects. In this study, the direct effect of OSC against neuronal injuries induced by oxygen and glucose deprivation (OGD) in neonatal rat primary-cultured hippocampal neurons and its mechanisms were investigated. Cultured hippocampal neurons, which were exposed to OGD for 2 h followed by a 24 h reoxygenation, were used as an in vitro model of ischemia and reperfusion. 2-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) assay were used to confirm neural damage and to further evaluate the protective effects of OSC. The concentration of intracellular-free calcium [Ca] and mitochondrial membrane potential (MMP) were measured to determine the intracellular mechanisms and to further estimate the degree of neuronal damage. Changes in expression of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, p-ERK1/2, p-JNK1/2, and p-p38 MAPK were also observed in the in vitro model. It was shown that OSC (0.8, 2, or 5 µmol/L) significantly attenuated the increased absorbance of MTT, and the release of LDH manifests the neuronal damage by the OGD/R. Meanwhile, the pretreatment of the neurons during the reoxygenation period with OSC significantly increased MMP; it also inhibited [Ca] the elevation in a dose-dependent manner. Furthermore, the pretreatment with OSC (0.8, 2, or 5 µmol/L) significantly down-regulated expressions of IL-1β, TNF-α, p-ERK1/2, p-JNK1/2, and p-p38 MAPK in neonatal rat primary-cultured hippocampal neurons induced by OGD/R injury. In conclusion, OSC displays a protective effect on OGD-injured hippocampal neurons by attenuating expression of inflammatory factors via down-regulated the MAPK signaling pathway.

Objective: This study investigated the protective effects of OSC on neonatal rat primary-cultured hippocampal neurons were injured by oxygen-glucose deprivation and reperfusion (OGD/RP). Materials and methods: Cultured hippocampal neurons were exposed to OGD for 2 h followed by a 24 h RP. OSC (1, 2, and 5 mmol/L) and nimodipine (Nim) (12 mmol/L) were added to the culture after OGD but before RP. The cultures of the control group were not exposed to OGD/ RP. MTT and LDH assay were used to evaluate the protective effects of OSC. The concentration of intracellular-free calcium [Ca 2+ ] i and mitochondrial membrane potential (MMP) were determined to evaluate the degree of neuronal damage. Morphologic changes of neurons following OGD/RP were observed with a microscope. The expression of caspase-3 and caspase-12 mRNA was examined by real-time quantitative PCR. Results: The IC 50 of OSC was found to be 100 mmol/L. Treatment with OSC (1, 2, and 5 mmol/L) attenuated neuronal damage (p50.001), with evidence of increased cell viability (p50.001) and decreased cell morphologic impairment. Furthermore, OSC increased MMP (p50.001), but it inhibited [Ca 2+ ] i (p50.001) elevation in a dose-dependent manner at OGD/RP. OSC (5 mmol/L) also decreased the expression of caspase-3 (p50.05) and caspase-12 (p50.05). Discussion and conclusion: The results suggested that OSC has significant neuroprotective effects that can be attributed to inhibiting endoplasmic reticulum (ER) stress-induced apoptosis.