• The Korean Journal of Pharmacology
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• v.31 no.2
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• pp.165-177
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• 1995

Dissociated cell cultures from rat embryonic ventral mesencephalon were used to evaluate the mechanisms of $MPP^+$ neurotoxicity. The cells were treated with MPTP or $MPP^+$ and the viability of the cells was assessed biochemically; tyrosine hydroxylase (TH) immunoreactivity, protein, intracellular ATP and lactate content and lipid peroxidation. Also the generation of the intracellular oxidants was measured after loading 2', 7‘-dichlorofluorescin diacetate to the cells. When cultures were exposed to 0.1 mM $MPP^+$, at 2 hour incubation lactate was significantly accumulated in the cells and then the intracellular ATP content and TH immunoreactivity were decreased dose- and time-dependently. But, malondialdehyde as an index for lipid peroxidation was not changed even though the generation of the intracellular oxidants was stimulated by the addition of $MPP^+$. On the other hand, 1 mM MPTP significantly reduced the TH immunoreactivity at 24 hour exposure without any change in the intracellular A TP, lactate and MDA content until 6 hour exposure. And also MPTP inhibited the generation of the intracellular oxidants from control cells and $MPP^+$ exposed cells. These results indicate that cytotoxicity of $MPP^+$ is mediated by inhibiting the mitochondrial energy metabolism rather than generating the intracellular oxidants. And MPTP would have direct action in addition to conveting to the toxic metabolite, $MPP^+$ to exert the toxicity on the dopaminergic neurons.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.2
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• pp.65-71
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• 2008

The present study examined the inhibitory effect of licorice compounds glycyrrhizin and a metabolite $18{\beta}$-glycyrrhetinic acid on the neurotoxicity of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in the mouse and on the 1-methyl-4-phenylpyridinium ($MPP^+$)-induced cell death in differentiated PC12 cells. MPTP treatment increased the activities of total superoxide dismutase, catalase and glutathione peroxidase and the levels of malondialdehyde and carbonyls in the brain compared to control mouse brain. Co-administration of glycyrrhizin (16.8 mg/kg) attenuated the MPTP effect on the enzyme activities and formation of tissue peroxidation products. In vitro assay, licorice compounds attenuated the $MPP^+$-induced cell death and caspase-3 activation in PC12 cells. Glycyrrhizin up to $100{\mu}M$ significantly attenuated the toxicity of $MPP^+$. Meanwhile, $18{\beta}$-glycyrrhetinic acid showed a maximum inhibitory effect at $10{\mu}M$; beyond this concentration the inhibitory effect declined. Glycyrrhizin and $18{\beta}$-glycyrrhetinic acid attenuated the hydrogen peroxide- or nitrogen species-induced cell death. Results from this study indicate that glycyrrhizin may attenuate brain tissue damage in mice treated with MPTP through inhibitory effect on oxidative tissue damage. Glycyrrhizin and $18{\beta}$-glycyrrhetinic acid may reduce the $MPP^+$ toxicity in PC12 cells by suppressing caspase-3 activation. The effect seems to be ascribed to the antioxidant effect.

• Journal of Acupuncture Research
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• v.32 no.1
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• pp.23-36
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• 2015

Objectives : This study was designed to investigate the neuroprotective effects of Hominis-Placenta (HP)on dopaminergic neurons. Methods : We examined the effect of invitro administration of HP against 1-methyl-4-phenylpyridinium( MPP+)-induced dopaminergic cell loss in primary mesencephalic culture and also used behavioral tests and performed analysis in the striatum and the substantia nigra of mouse brain, to confirm the effect of HP on dopaminergic neurons in an invivo 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced PD mouse model. Animals were assigned to four groups: (1) Group 1(vehicle-treatedgroup), (2) Group 2(MPTPonlytreated group), (3) Group 3(MPTP+ saline-treated/$ST_{36}$ group), and (4) Group 4(MPTP+HP-treated/$ST_{36}$ group). HP at $20{\mu}L$ of 48 mg/kg dose was injected at $ST_{36}$ for 4 weeks at 2-day intervals. MPTP in saline was injected intraperitoneally each day for 5 days from the $8_{th}$ treatment of HP. We performed the pole test and rota-rod test on the first and seventh day after the last MPTP injection. To investigate the effect of HP on dopaminergic neurons, we performed analysis in the striatum and the substantia nigra of mouse brain after treatment with HP and/or MPTP. Results : Treatment with HP had no influence on cell proliferation and caused no cell toxicity in $PC_{12}$ and $HT_{22}$ cells. Our study showed that HP significantly prevented cell loss and protected neurites against MPP+ toxicity. Although the invivo treatment of HP herbal acupuncture at $ST_{36}$ showed a tendency to improve movement ability and protected dopaminergic cells and fibers in the substantia nigra and the striatum, it did not show significant changes compared with the MPTP treated group. Conclusions : These data suggest that HP could be a potential treatment strategy in neurodegenerative diseases such as Parkinson's disease.

• Journal of Oriental Neuropsychiatry
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• v.23 no.1
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• pp.129-143
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• 2012

Objectives : To evaluate the neuroprotective effects of the essential oil from Sohaphwangwon (SH), a Chinese traditional medicinal prescription in a Parkinson's disease mouse model. Methods : 1. The neuroprotective effect of SH on primary neuronal cells was examined by using 1-methyl-4-phenylpyridinium ion (MPP+). 2. The neuroprotective effect of SH was examined in a Parkinson's disease mouse model. C57BL/6 mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg/day), intraperitoneal (i.p.) for 5 days. SH inhalation was applied before MPTP treatment for 7 days and continued until 12 days after the first MPTP treatment. 3. To find out the intracellular target signal molecule(s) regarding the neuroprotective effect of SH essential oil, brain-derived neurotropic factor (BDNF) and synaptic protein SNAP25 were examined by Western blot analysis. Results : 1. MPP+ induced a concentration-dependent decrease in cell viability. However, in the presence of 3 and 5 ug/ml of SH, MPP+-induced cell death was significantly reduced. 2. SH inhalation in MPTP mice led to the restoration of behavioral impairment and rescued tyrosine hydroxylase (TH)-positive dopaminergic neurodegeneration. 3. In SH / MPTP mice, BDNF and SNAP25 increased. Conclusions : This experiment suggests that the neuroprotective effect of SH essential oil is mediated by the expression of BDNF. Furthermore, SH essential oil may serve as a potential preventive or therapeutic agent regarding Parkinson's disease.

• The Korea Journal of Herbology
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• v.28 no.5
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• pp.21-28
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• 2013

Objectives : The aim of this study was to investigate the neuroprotective effects and mechanisms of Cyperi Rhizoma extracts (CRE) using in vitro and in vivo models of Parkinson's disease (PD). Methods : We evaluated the neuroprotective effect of CRE against 1-methyl-4-phenylpyridinium (MPP+) toxicity using tyrosine hydroxylase immunohistochemistry (IHC) in primary rat mesencephalic dopaminergic neurons. In addition, the effect of CRE was evaluated in mice PD model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). For evaluations, C57bl/6 mice were orally treated with CRE 50 mg/kg for 5 days and were injected intraperitoneally with MPTP (20 mg/kg) at 2 h intervals on the last day. To identify the CRE affects on MPTP-induced neuronal loss of dopaminergic neurons in substantia nigra pars compacta (SNpc) and striatum of mice, the behavioral tests and IHC analysis were carried out. Also, we conducted nitric oxide (NO) and tumor necrosis factor-alpha (TNF-${\alpha}$) assay in dopaminergic neurons and IHC using glial markers in SNpc of mice to assess the anti-inflammation effects. Results : In primary mesencephalic culture system, CRE protected dopaminergic cells against $10{\mu}M$ MPP+-induced toxicity at 0.2 and $1.0{\mu}g/mL$. In the behavior tests, CRE treated group showed improved motor deteriorations than those in the MPTP only treated group. CRE significantly protected striatal dopaminergic damage from MPTP-induced neurotoxicity in mice. Moreover, CRE inhibited productions of NO and TNF-${\alpha}$ in dopaminergic culture system and activation of astrocyte and microglia in SNpc of the mice. Conclusion : We concluded that CRE shows anti-parkinsonian effect by protecting dopaminergic neurons against MPP+/MPTP toxicities through anti-inflammatory actions.

• Toxicological Research
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• v.9 no.2
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• pp.217-224
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• 1993

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a well-known dopamine neuron-specific toxin. But the involvement of oxidative damage in the pathogenesis of MPTP-induced parkinsonism is still uncertain. In this study, by using 2',7',-dichlorofluorescin diacetate(DCFH-DA) that detects intracellular oxidative processes, the effect of MPTP on dichlorofluorescein fluorescence in dissociated cells from fetal rat mesencephalon in culture was investigated. At 7th day in culture, cells were loaded with DCFH-DA, and exposed to 1 mM MPTP or MPP+. MPTP induced dichlorofluorescein-fluorescence which was peaked at 3 min and mostly faded away 30 min after MPTP treatment.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.266-273
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• 2006

This study is investigated the effect of selenium against neurotoxicity induced by MPTP(1-methy-4-phenyl-propion-oxypiperidine) in mice. In order to demonstrate neuroprotective activity of selenium, mice were administrated orally with selenium(25, 50, 100 ${\mu}g/kg$, once/day) for 10 days, and MPTP(10 mg/kg) was injected subcutaneously into the mice for 6 days from the beginning 1hr before selenium treatment. Test of rota road activity was inhibited by treatment with selenium in MPTP-induced neurotoxicity group when compared to MPTP treatment group in normal mice. Monoamine oxidase(MAO)-B activity and cerebral lipid peroxide content were significantly decreased in the treatment of selenium in MPTP-induced neurotoxicity group when compared to MPTP treatment group in normal mice and MAO-A was not affected. Activities of cerebral superoxide dismutase, catalase and glutathione peroxidase were significantly increased in the treatment of selenium in MPTP-induced neurotoxicity group when compared to MPTP treatment group in normal mice. These results suggest that selenium might be estimated the result from the cooperative action of its inhibitory effect on monoamine oxidase-B with that of the enhancement of antioxidant(SOD, catalase, GSH-Px) defence ability.

• YAKHAK HOEJI
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• v.41 no.1
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• pp.86-93
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• 1997

Even though both N-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) and 6-hydroxydopamine have been widely used to establish the experimental model for dopaminergic neuronal ce ll death. mechanisms underlying this phenomenon have not been firmly explored. To investigate how these dopaminergic neurotoxins induce neuronal cell death, murine dopaminergic neuronal cell line, MN9D cells were treated with various concentration of either 6-hydroxydopamine or active form of MPTP, N methyl-4-phenylpyridinium (MPP$^+$). Treatment of cells with 5-100 uM 6-hydroxydopamine resulted in apoptotic cell death whereas cell death induced by 5~50 uM MPP$^+$ was not demonstrated typical apoptotic characteristics such as cell shrinkage, apoptotic body and nuclear condensation. Cell death induced by 6-hydroxydopamine was partially blocked in the presence of antioxidants including soluble form of vitamin E or desferrioxamine suggesting that generation of oxidative stress may be associated with 6-hydroxydopamine-induced cell death in MN9D cells. In contrast, MPP$^+$-induced cell death was not blocked by treatment with any of antioxidants tested. As previously demonstrated that MPP$^+$ caused metabolic alterations such as glucose metabolism, removal of glucose from the medium partially inhibited MPP$^+$-induced cell death suggesting excessive cycles of glycolysis may be associated with MPP$^+$-induced cell death. Taken together, these studies demonstrate that two types of dopaminergic neurotoxins recruit distinct neuronal cell death pathways.

• The Korea Journal of Herbology
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• v.29 no.3
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• pp.27-33
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• 2014

Objectives : The aim of this study was to investigate the protective effect of extract of Thuja orientalis leaves (TOFE) against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity by inhibition of inflammation in in vitro and in vivo models of Parkinson's disease (PD). Methods : We evaluated the effect of TOFE against lipopolysaccharide (LPS)/1-methyl-4-phenylpyridinium ($MPP^+$) toxicity using nitric oxide (NO) assay, inducible NO synthase and cyclooxygenase 2 western blot, tyrosine hydroxylase and microglia activation immunohistochemistry (IHC) in BV2 cell, primary rat mesencephalic neurons, or C57BL/6 mice. We also evaluated the effect of TOFE in mice PD model induced by MPTP. C57BL/6 mice were treated with TOFE 50 mg/kg for 5 days and were injected intraperitoneally with four administrations of MPTP on the last day. We conducted behavioral tests and IHC analysis to see how TOFE affect MPTP-induced neuronal loss of dopaminergic neurons in substantia nigra pars compacta (SNpc) and striatum (ST) of mice. To assess the anti-inflammation effects, we carried out glial fibrillary acidic protein and macrophage-1 antigen integrin alpha M in IHC in SNpc and ST of mice. Results : In an in vitro system, TOFE decreasesd NO generations in BV2 cells. TOFE protected dopaminergic cells against LPS or $MPP^+$-induced toxicity in primary mesencephalic dopaminergic neurons. In vivo system, TOFE at 50 mg/kg treated group showed improved motor deteriorations than the MPTP only treated group and TOFE significantly protected striatal dopaminergic damage from MPTP-induced neurotoxicity in mice. Moreover, TOFE inhibited activation of astrocyte and microglia in SNpc and ST of the mice. Conclusions : We concluded that TOFE showed anti-parkinsonian effect by protection of dopaminergic neurons against MPTP toxicity through anti-inflammatory actions.

• BMB Reports
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• v.44 no.5
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• pp.312-316
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• 2011

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its toxic metabolite 1-methyl-4-phenylpyridium ion (MPP$^+$) have been shown to induce Parkinson's disease-like symptoms as well as neurotoxicity in humans and animal species. Recently, we reported that maintenance of redox balance and cellular defense against oxidative damage are primary functions of the novel antioxidant enzyme cytosolic NADP$^+$-dependent isocitrate dehydrogenase (IDPc). In this study, we examined the role of IDPc in cellular defense against MPP$^+$-induced oxidative injury using PC12 cells transfected with IDPc small interfering RNA (siRNA). Our results demonstrate that MPP$^+$-mediated disruption of cellular redox status, oxidative damage to cells, and apoptotic cell death were significantly enhanced by knockdown of IDPc.