Ah-Reum Doo

Neuroprotective effects of an herbal medicine, Yi-Gan San on MPP+/MPTP-induced cytotoxicity in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE A traditional herb, Yi-Gan San, has been widely used for the management of neurodegenerative disorders in traditional East Asian Medicine. AIM OF THE STUDY The present study investigated the neuroprotective effects of Yi-Gan San in 1-methyl-4-phenylpyridine/1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced cytotoxicity in vitro and in vivo and sought to clarify its underlying mechanisms. MATERIALS AND METHODS The effect of Yi-Gan San on 1-methyl-4-phenylpyridine was measured in terms of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assays, caspase-3 activity, and western blot analysis of phosphorylated Akt, one of the survival-related signaling proteins in SH-SY5Y cells. The effects of Yi-Gan San were also confirmed in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinsonian mouse model using a rotarod test and tyrosine hydroxylase-immunohistochemistry. RESULTS Pretreatment of Yi-Gan San with 1-methyl-4-phenylpyridine showed a significant protective effect on SH-SY5Y cells and significantly decreased the level of caspase-3 activity compared to the values for the 1-methyl-4-phenylpyridine-treated cells. This process increased the protein expressions of phosphorylated Akt, and an inhibitor of phosphatidylinositol 3-kinase (PI3K)/Akt, LY294002, significantly decreased this protective effect of Yi-Gan San. In the mouse Parkinsons disease model, treatment with Yi-Gan San also significantly improved motor functioning and prevented dopaminergic loss related to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine challenge. CONCLUSION Using both in vitro and in vivo methods, this study revealed that Yi-Gan San has neuroprotective effects and rescues dopaminergic neurons from 1-methyl-4-phenylpyridine/1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity, possibly via the PI3K/Akt pathway.

Acupuncture Enhances the Synaptic Dopamine Availability to Improve Motor Function in a Mouse Model of Parkinson's Disease

Parkinsons disease (PD) is caused by the selective loss of dopaminergic neurons in the substantia nigra (SN) and the depletion of striatal dopamine (DA). Acupuncture, as an alternative therapy for PD, has beneficial effects in both PD patients and PD animal models, although the underlying mechanisms therein remain uncertain. The present study investigated whether acupuncture treatment affected dopamine neurotransmission in a PD mouse model using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We found that acupuncture treatment at acupoint GB34 improved motor function with accompanying dopaminergic neuron protection against MPTP but did not restore striatal dopamine depletion. Instead, acupuncture treatment increased dopamine release that in turn, may lead to the enhancement of dopamine availability in the synaptic cleft. Moreover, acupuncture treatment mitigated MPTP-induced abnormal postsynaptic changes, suggesting that acupuncture treatment may increase postsynaptic dopamine neurotransmission and facilitate the normalization of basal ganglia activity. These results suggest that the acupuncture-induced enhancement of synaptic dopamine availability may play a critical role in motor function improvement against MPTP.

Bee venom protects SH-SY5Y human neuroblastoma cells from 1-methyl-4-phenylpyridinium-induced apoptotic cell death.

Parkinsons disease (PD) is a progressive neurodegenerative disorder characterized by progressive selective loss of dopaminergic neurons in the substantia nigra. Recently, bee venom was reported to protect dopaminergic neurons in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine induced mice PD model, however, the underlying mechanism is not fully understood. The objective of the present study is to investigate the neuroprotective mechanism of bee venom against Parkinsonian toxin, 1-methyl-4-phenylpyridine (MPP(+)), in SH-SY5Y human neuroblastoma cells. Our results revealed that bee venom pretreatment (1-100 ng/ml) increased the cell viability and decreased apoptosis assessed by DNA fragmentation and caspase-3 activity assays in MPP(+)-induced cytotoxicity in SH-SY5Y cells. Bee venom increased the anti-apoptotic Bcl-2 expression and decreased the pro-apoptotic Bax, cleaved PARP expressions. In addition, bee venom prevented the MPP(+)-induced suppression of Akt phosphorylation, and the neuroprotective effect of bee venom against MPP(+)-induced cytotoxicity was inhibited by a phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002. These results suggest that the anti-apoptotic effect of bee venom is mediated by the cell survival signaling, the PI3K/Akt pathway. These results provide new evidence for elucidating the mechanism of neuroprotection of bee venom against PD.

Phosphatidylinositol 3-kinase/Akt Signaling Pathway Mediates Acupuncture-Induced Dopaminergic Neuron Protection and Motor Function Improvement in a Mouse Model of Parkinson's Disease

ABSTRACT It has been reported that acupuncture treatment reduced dopaminergic neuron degeneration in Parkinsons disease (PD) models. However, the mechanistic pathways underlying, such neuroprotection, are poorly understood. Here, we investigated the effects and the underlying mechanism of acupuncture in a mouse model of PD using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). First, we observed that MPTP-induced impairment of Akt activation, but not MPTP-induced c-Jun activation, was effectively restored by acupuncture treatment in the substantia nigra. Furthermore, we demonstrated for the first time that the brain-specific blockade of phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway, by intranasal administration of LY294002, a specific inhibitor of PI3K/Akt signaling pathway, significantly blocked acupuncture-induced dopaminergic neuron protection and motor function improvement. Our results provide evidence that PI3K/Akt signaling pathway may play a central role in the mechanism underlying acupuncture-induced benefits in Parkinsonian mice.