Neuroprotective effects of kukoamine A on 6-OHDA-induced Parkinson's model through apoptosis and iron accumulation inhibition / 中草药·英文版

Objective: Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in substantia nigra (SN). Our previous study demonstrated kukoamine A (KuA) to exhibit strong neuroprotective effects through antioxidative stress, and autophagy in MPTP/MPP

6-hydroxydopamine and ovariectomy has no effect on heart rate variability parameters of females

OBJECTIVES: In addition to the classic motor symptoms of Parkinson's disease (PD), patients also present with non-motor symptoms, such as autonomic dysfunction, which is present in almost 90% of patients with PD, affecting the quality of life and mortality. Regarding sex differences in prevalence and presentation, there is increasing concern about how sex affects autonomic dysfunction. However, there are no previous data on autonomic cardiac function in females after 6-hydroxydopamine (6-OHDA) striatal injection. METHODS: Wistar female rats were ovariectomized. After 20 days, the animals received bilateral injections of 6-OHDA (total dose per animal: 48 µg) or a vehicle solution in the striatum. Thirty days after 6-OHDA injection, subcutaneous electrodes were implanted for electrocardiogram (ECG) recording. Ten days after electrode implantation, ECG signals were recorded. Analyses of heart rate variability (HRV) parameters were performed, and the 6-OHDA lesion was confirmed by analyzing the number of tyrosine hydroxylase-positive neurons in the substantia nigra pars compacta (SNpc). RESULTS: A high dose of 6-OHDA did not affect HRV of females, independent of ovariectomy. As expected, ovariectomy did not affect HRV or lesions in the SNpc after 6-OHDA injection. CONCLUSIONS: We suggest that females with 6-OHDA present with cardioprotection, independent of ovarian hormones, which could be related to female vagal predominance.

Memantine inhibits 6-OHDA-induced apoptosis PC12 cells via the Nurr77 and caspase pathway

Objective: To investigate the effect of memantine on Parkinson's disease cell models. Methods: Parkinson's disease cell models were established using PC12 cells incubated with 6-hydroxydopamine (6-OHDA). Flow cytometry and microscopy were used to investigate the apoptotic process and the percentage of different apoptotic stages. PC12 cells were infected with lentiviral vectors to knockdown Nur77. Western blotting was used to detect the expression of Nur77 and caspase -3, -8, -9, -12 in PC12 cells withdifferent concentrations of 6-OHDA or 6-OHDA+memantine. Results: 6-OHDA led to apoptosis PC12 cells, and increased the expression of Nur77 and caspases. Memantine significantly inhibited 6-OHDA-induced apoptosis of PC12 cells. Meanwhile, memantine could mitigate apoptosis of PC12 cells by regulating the Nur77 and caspase pathway. Conclusions: Memantine has a protective effect on the PC12 cell model via regulating the Nur77 and caspases pathway.

Memantine inhibits 6-OHDA-induced apoptosis PC12 cells via the Nurr77 and caspase pathway

Objective: To investigate the effect of memantine on Parkinson's disease cell models. Methods: Parkinson's disease cell models were established using PC12 cells incubated with 6-hydroxydopamine (6-OHDA). Flow cytometry and microscopy were used to investigate the apoptotic process and the percentage of different apoptotic stages. PC12 cells were infected with lentiviral vectors to knockdown Nur77. Western blotting was used to detect the expression of Nur77 and caspase -3, -8, -9, -12 in PC12 cells withdifferent concentrations of 6-OHDA or 6-OHDA+memantine. Results: 6-OHDA led to apoptosis PC12 cells, and increased the expression of Nur77 and caspases. Memantine significantly inhibited 6-OHDA-induced apoptosis of PC12 cells. Meanwhile, memantine could mitigate apoptosis of PC12 cells by regulating the Nur77 and caspase pathway. Conclusions: Memantine has a protective effect on the PC12 cell model via regulating the Nur77 and caspases pathway.

Research progress on animal models of Parkinson's disease / 中国比较医学杂志

Parkinson's disease(PD)is a progressive neurodegenerative disorder, with an etiology that is now considered to be due to interaction between genetic and environmental factors. Typical PD features include loss of dopaminergic neurons in the nigrostriatal region, with typical motor traits of PD associated with dopamine deficiency. Animal models have contributed to determining PD etiology and pathogenesis,as well as testing new therapeutic schedules and novel drug research. Rodents, tree shrews, primates, and other animal models of PD have been established by different method. These models each have their own advantages and limitations, showing different clinical features and pathological mechanisms to those in humans. Therefore, the appropriate model for scientific research must be carefully considered. This article reviews the main neurotoxic and transgenic models of PD.

Expression and significance of MeCP2 and TH protein in normal SH-SY5Y cells and Parkinson's disease cell model / 国际检验医学杂志

Objective To investigate the expression and significance of TH and MeCP2 protein in normal SH-SY5Y cells and Parkinson's disease cell model.Methods The experiment was divided into 3 groups:blank control group,non transfection;model control group;pEGFP-N1-MeCP2 group,transfection solution added to the recombinant pEGFP-N1-MeCP2 plasmid.In addition to the blank group,the remaining two groups were added 50.0 μmol/L 6-OHDA treatment for 24 hours.CCK-8 assay and flow cytometry were used to detect cell activity and apoptosis in normal SH-SY5Y cells and the SH-SY5Y cell with up-regulation of MeCP2 induced by 6-OHDA.Immunofluorescence and Western blot analysis were used to detect the changes of MeCP2 protein and TH protein expression in each group of SH-SY5Y cells.Results As for the cell survival and apoptosis of SH-SY5Y cells detected by CCK-8 assay and induced 6-OHDA of flow cytometry and SH-SY5Y cells with up-regulation of MeCP2 in model control group,compared to those in pEGFP-N1-MeCP2 group and the thank control group,the difference was statistically significant (P＜0.05).The expression of MeCP2 and TH in SH-SY5Y induced 6-OHDA cells was detected by double immunofluorescence,it was found that in model control group,with 6-OHDA (50.0 μmol/L) inducing for 24 hours,and the expression of MeCP2 and TH decreased significantly (P＜0.05).After Western blot was used to detect the up-regulation of MeCP2 expression,in 6-OHDA induced SH-SY5Y cells of MeCP2 and TH expression,the expression of MeCP2 and TH protein in pEGFP-N1-MeCP2 group and blank control group was statistically different from that in model control group (P＜0.01).Conclusion The transfection of pEGFP-N1-MeCP2 recombinant plasmid could inhibit the apoptosis of SH-SY5Y cells induced by 6-OHDA,improve the expression of TH and increase the cell survival rate.

Determination of salsolinol N-methyltransferase activity in 6-OHDA-lesioned rats / 中国比较医学杂志

Objective The aim of this study was to establish a rat model of Parkinson''s disease ( PD) by using 6-hydroxydopamine (6-OHDA) and detect the salsolinol N-methyltransferase ( SNMT) activity in peripheral lymphocytes of PD rats for the development of a biomarker for early diagnosis of PD. Methods Rat model of PD was established by unilateral double-pointed injection of 6-OHDA into the striatum and was verified by behavior observation. An analytical method was developed based on multiple reaction monitoring with HPLC-ESI-QQQ to determine the SNMT activity in peripheral lymphocytes. Results Seven of 18 rats injected with 6-OHDA showed steadily apomorphine-induced rotation ( >7 r/min) . The success rate was 38. 9%. A sensitive and stable quantitative method with internal standard added was created, based on multiple reaction monitoring mode to analyze SNMT activity. The limit of detection ( LOD) and limit of quantitation ( LQD) of N-methyl-salsolinol, which is the product of Salsolinol catalyzed by SNMT, were 49 pmol/L and 98 pmol/L, respectively. The precisions of intra-day and inter-day assays both were below 6. 0%. SNMT activity of peripheral lymphocytes in the 6-OHDA-lesioned rats was significantly increased [43. 37 ±9. 49 pmol/(h·mg)NMSal] in comparison with that in the normal group [2. 16 ±5. 82 pmol/(h·mg)NMSal] and the sham-operated group [0. 58 ±2. 32 pmol/(h· mg)NMSal](P< 0. 01, n=5). There was no significant difference between the normal group and sham-operated group (P< 0. 05, n =5). Conclusions Our results indicate that SNMT activity may reflect the changes in the course of Parkison''s disease and may become a potential clinical biomarker in diagnosis of this disease.

Effects of 5-HT1A receptor in hippocampal dentate gyrus on anxiety-related behavior of adult rats with Parkinson's disease / 西安交通大学学报(医学版)

Objective To study the effects of 5-HT1A receptor in hippocampal dentate gyrus on anxiety behavior of adult rats with Parkinson's disease (PD).Methods PD model in rats was constructed by using 6-hydroxydopamine (6-OHDA) to lesion the medial forebrain bundle (MFB).In lesioned rats and sham-operated rats,we examined the changes of the number of TFH-positive neurons in the SNc and VTA.We also examined how 5-HT1A receptor of hippocampal dentate gyrus (DG) modulates the anxiety-related behavior using open field test and elevated plus-maze test,and examined monoamine neurotransmitter changes in the striatum,medial prefrontal cortex (mPFC),amygdale and ventral hippocampus using reverse-phase high performance liquid chromatography with electrochemical detection.Results In 6-OHDA-lesioned rats,the SNc of the injected side showed a total loss of TH-ir neurons compared with the unlesioned side,and the number of TH-ir neurons in the VTA on the lesioned side decreased significantly to (34± 2)％.The locomotor activity in 6-OHDA-lesioned rats decreased compared with that in sham-operated rats.Unilaterally lesioning the MFB decreased the percentage of time spent in the center in the open-field test and percentages of open arm entries and open arm time of elevated plus maze test when compared with sham-operated rats.In the sham-operated rats,intra-DG injection of 8-OH-DPAT did not affect anxiety-like behavior.In 6-OHDA-lesioned rats,intra-DG injection of 8-OH-DPAT significantly increased the percentage of time spent in the center at a dose of 100 ng and 500 ng when compared with saline injection into the DG.Injection of WAY-100635 did not affect rats in the two groups.Unilateral 6-OHDA lesions of the MFB in rats significantly decreased DA levels in the ipsilateral striatum,mPFC,amygdale and ventral hippocampus compared with those in sham-operated rats,but had no effect on 5-HT or NA levels in those structures.Conclusion Unilateral 6-OHDA lesion of the MFB not only totally damaged DA neurons in SNc and partly damaged DA neurons in VTA,but also decreased DA level in the ipsilateral striatum,mPFC,amygdale and ventral hippocampus.Unilateral 6-OHDA lesion of the MFB induces anxiety-related behavior,and activation of 5-HT1A receptor in the hippocampal dentate gyrus has anxiolytic effect in the rat model of Parkinson's disease.

Efeito do ácido tânico sobre a toxicidade induzida pela 6-OHDA em células PC12, um modelo in vitro de doença de Parkinson

A doença de Parkinson (DP) é a segunda forma mais comum de doença neurodegenerativa nos idosos. É caracterizada pela perda progressiva de neurônios dopaminérgicos na substância negra pars compacta, levando a uma severa redução do conteúdo de dopamina no estriado. O modelo utilizando células PC12, uma linhagem celular de feocromocitoma de rato, exposta a diferentes toxinas que recapitulam mecanismos de morte celular na DP, vem sendo utilizado como screeningpara testar agentes neuroprotetores. Dentre os principais mecanismos que levam à morte celular nas doenças neurodegenerativas, incluindo a DP, a inflamação, a apoptose e o estresse oxidativo assumem um papel importante.O Ácido Tânico (AT) é um polifenol com efeito antioxidante do tipo quelante e sequestrador de radicais livres. O objetivo do presente estudo foi avaliar o possível efeito citoproterordo AT sobre a citotoxicidade induzida por 6-OHDA em células PC12...

Parkinson's disease (PD) is the second most common neurodegenerative disease in the elderly. It is characterized by progressive loss of dopaminergic neurons in the substantia nigra pars compacta, leading to a severe reduction in striataldopamine content. The PC12 cells are a cell line of rat pheochromocytoma and represents an experimental model of PD when it is exposed to toxins like the 6-hydroxydopamine (6-OHDA). This recapitulate differents mechanisms of cell death in PD and has been used as a screening test for neuroprotective agents. Inflammation, apoptosis and oxidative stress play an important role among the major mechanisms that lead to cell death in neurodegenerative diseases including PD. The tannic acid (TA) is a polyphenol that has a antioxidant effect as a chelating and sequestering free radicals. The aim of this study was to evaluate the possible citoproteror effect of TA on the cytotoxicity induced by 6-OHDA in PC12 cells...

Effects of Hypericum perforatum on turning behavior in an animal model of Parkinson's disease

Parkinson's disease (PD) is an age-related neurodegenerative disorder characterized by the slow and progressive death of dopaminergic neurons in the (substantia nigra pars compact). Hypericum perforatum (H. perforatum) is a plant widely used as an antidepressant, that also presents antioxidant and anti-inflammatory properties. We evaluated the effects of H. perforatum on the turning behavior of rats submitted to a unilateral administration of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle as an animal model of PD. The animals were treated with H. perforatum (100, 200, or 400 mg/kg, v.o.) for 35 consecutive days (from the 28th day before surgery to the 7th day after). The turning behavior was evaluated at 7, 14 and 21 days after the surgery, and the turnings were counted as contralateral or ipsilateral to the lesion side. All tested doses significantly reduced the number of contralateral turns in all days of evaluation, suggesting a neuroprotective effect. However, they were not able to prevent the 6-OHDA-induced decrease of tyrosine hydroxylase expression in the lesioned striatum. We propose that H. perforatum may counteract the overexpression of dopamine receptors on the lesioned striatum as a possible mechanism for this effect. The present findings provide new evidence that H. perforatum may represent a promising therapeutic tool for PD.

A Doença de Parkinson é uma doença neurodegenerativa relacionada à idade, caracterizada pela morte lenta e progressiva de neurônios dopaminérgicos da substância negra pars compacta. O Hypericum perforatum (H. perforatum) é um fitoterápico utilizado como antidepressivo, apresentando propriedades antioxidantes, anti-inflamatórias e nootrópicas. Neste trabalho, avaliaram-se os efeitos do tratamento com H. perforatum no comportamento rotatório de ratos no modelo da doença de Parkinson induzido pela administração unilateral de 6-OHDA no feixe prosencefálico medial. Ratos Wistar machos foram tratados com H. perforatum (100, 200 ou 400 mg/kg, v.o.) por 35 dias (do 28º dia antes até o 7º dia após a lesão). As rotações ipsilaterais e contralaterais à lesão foram registradas no 7º, 14º e 21º dias após a cirurgia. As três doses de H. perforatum utilizadas reduziram o número de rotações contralaterais, indicando um possível efeito neuroprotetor da planta. Porém, o H. perforatum não impediu a redução na expressão da enzima tirosina hidroxilase no estriado lesionado, quantificada por Western blot. Propomos que o H. perforatum possa bloquear o aumento da expressão dos receptores dopaminérgicos no estriado lesionado com 6-OHDA. Entretanto, estudos adicionais são necessários para identificar o mecanismo exato pelo qual o H. perforatum reduziu o número de rotações contralaterais. Os resultados do presente estudo sugerem o H. perforatum como um potencial agente terapêutico para a doença de Parkinson.

Modeling Parkinson's disease in the common marmoset (Callithrix jacchus): overview of models, methods, and animal care / 한국실험동물학회지

The common marmoset (Callithrix jacchus) is a small-bodied, popular New World monkey and is used widely in reproductive biology, neuroscience, and drug development, due to its comparative ease of handling, high reproductive efficiency, and its unique behavioral characters. In this review, we discuss the marmoset models in Parkinson's disease (PD), which is a neurological movement disorder primarily resulting from a degeneration of dopaminergic neurons with clinical features of tremor, rigidity, postural instability, and akinesia. The most common PD models involve the administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or 6-hydroxydopamine to study the pathogenesis and to evaluate novel therapies. Following the systemic or local administration of these neurotoxins, the marmosets with very severe Parkinson's symptoms are recommended to be placed in an intensive care unit with artificial feeding to increase survival rate. All procedures with MPTP should be conducted in a special room with enclosed cages under negative-pressure by trained researchers with personal protection. Behavioral tests are conducted to provide an external measure of the brain pathology. Along with several biomarkers, including alpha-synuclein and DJ-1, non-invasive neuroimaging techniques such as positron emission tomography and magnetic resonance imaging are used to evaluate the functional changes associated with PD. With the recent growing interest in potential and novel therapies such as stem cell and gene therapy for PD in Korea, the marmoset can be considered as a suitable non-human primate model in PD research to bridge the gap between rodent studies and clinical applications.

Effect of DHEA on Recovery of Muscle Atrophy Induced by Parkinson's Disease

PURPOSE: The purpose of this study was to determine the effect of dehydroepiandrosterone (DHEA) on recovery of muscle atrophy induced by Parkinson's disease. METHODS: The rat model was established by direct injection of 6-hydroxydopamine (6-OHDA, 20 microg) into the left striatum using stereotaxic surgery. Rats were divided into two groups; the Parkinson's disease group with vehicle treatment (Vehicle; n=12) or DHEA treatment group (DHEA; n=22). DHEA or vehicle was administrated intraperitoneally daily at a dose of 0.34 mmol/kg for 21 days. At 22-days after DHEA treatment, soleus, plantaris, and striatum were dissected. RESULTS: The DHEA group showed significant increase (p<.01) in the number of tyrosine hydroxylase (TH) positive neurons in the lesioned side substantia nigra compared to the vehicle group. Weights and Type I fiber cross-sectional areas of the contralateral soleus of the DHEA group were significantly greater than those of the vehicle group (p=.02, p=.00). Moreover, extracellular signal-regulated kinase (ERK) phosphorylation significantly decreased in the lesioned striatum, but was recovered with DHEA and also in the contralateral soleus muscle, Akt and ERK phosphorylation recovered significantly and the expression level of myosin heavy chain also recovered by DHEA treatment. CONCLUSION: Our results suggest that DHEA treatment recovers Parkinson's disease induced contralateral soleus muscle atrophy through Akt and ERK phosphorylation.

Effects of 6-hydroxydopamine on the Adult Neurogenesis of Dopaminergic Neurons in the Mouse Midbrain

Recently, restricted progenitor cells have been identified in the substantia nigra (SN) of the rat and mouse, raising a hope that resident stem/progenitor cells may be useful for the therapy of Parkinson's disease. However, it is controversial whether dopamine (DA) neurons can be spontaneously or injury-dependently generated from the endogenous stem cells in the adult brain. Here, we explored the neurogenesis in C57Bl/6 adult mice under the normal and neurotoxin-injured conditions. To monitor adult neurogenesis, we injected 5-bromodeoxyuridine (BrdU) 2 weeks after striatal injection of neurotoxin 6-hydroxydopamine (6-OHDA), and sacrificed the animals 6 weeks after 6-OHDA injection. Whereas the number of BrdU-labeled cells was slightly increased in ipsilateral side than contralateral side of the midbrain, none of BrdU- labeled cells, however, exhibited neuronal markers, NeuN or DCX. Instead, BrdU- labeled cells expressed glial markers such as GFAP (astrocyte), Olig2 (oligodendrocyte) and Iba-1 (microglia). Especially, larger portion of BrdU-labeled cells in the ipsilateral side exhibited microglial marker, indicating that increased cell production in response to the 6-OHDA injection is not related to the adult neurogenesis.

Study of Dominant-positive Heat Shock Factor 1 on 6-OHDA-induced Cell Death / 中国生物工程杂志

In eukaryotic cells,heat shock factor 1 is the main specific transcription factor mediating the enhanced expression of heat shock proteins when cells experience stresses.It is kept in a latent state by inhibitory complexes under unstressed conditions.It is only transiently activated in response to diverse forms stresses.Dominant-positive heat shock factor 1 has been developed through deletion-mutation.It can activate the expression of endogenous heat shock proteins in the absence of stresses.Environmental neurotoxins play an important role in the pathogenesis of Parkinson's disease.The neurotoxins induce cell death of dopamine neurons through oxidative damage.The results of Western blot and dual-luciferase analysis indicate that the expression of HSP70 was greatly up-regulated in dopaminergic SH-SY5Y cells transfected with dominant-positive heat shock factor 1.To investigate the effect of dominant-positive heat shock factor 1 on 6-OHDA-induced apoptosis in dopaminergic SH-SY5Y cells,the release of lactate dehydrogenase was detected.The result argues that dominant-positive heat shock factor 1 significantly inhibits neurotoxin 6-OHDA-induced cell death in SH-SY5Y cells.The cyto-protective role may be attributed to HSP70 activated by dominant-positive heat shock factor 1.Taken together,it is possible that dominant-positive heat shock factor 1 can be used to prevent or cure Parkinson's disease.

1alpha,25-Dihydroxyvitamin D3 Protects Dopaminergic Neurons in Rodent Models of Parkinson's Disease through Inhibition of Microglial Activation

BACKGROUND: Recent studies have demonstrated the molecular basis of the immunomodulatory and anti-inflammatory activities of 1,25-dihydroxyvitamin D3(1,25-(OH)2D3). This hormone improves behavioral deficits and normalizes the nigral dopamine levels in animal models of Parkinson's disease (PD). METHODS: We studied whether the administration of 1,25-(OH)2D3 would protect against 6-hydroxydopa (6-OHDA)- and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neuronal injury, and its potential regulatory effect on microglia activation. RESULTS: We found that 1,25-(OH)2D3 pretreatment significantly decreased 6-OHDA- and MPTP-induced dopaminergic neuronal loss in the substantia nigra pars compacta by preventing the activation of microglia. This observed neuroprotective effect in MPTP-treated mice that were given 1,25-(OH)2D3 may be attributable to inhibition of proinflammatory cytokine expression. CONCLUSION: These results suggest that 1,25-(OH)2D3 is a potentially valuable neuroprotective agent; it may therefore be considered for the treatment of pathologic conditions of the central nervous system, such as PD, where inflammation-induced neurodegeneration occurs.

Baicalein Protects 6-OHDA-induced Neuronal Damage by Suppressing Oxidative Stress

The protective effects of baicalein, one of the flavonoids in Scutellaria baicalensis Georgi, were evaluated against 6-hydroxydopamine (6-OHDA)-induced neuronal damage in mice and cultured human neuroblastoma cells. Nigrostriatal damage was induced by stereotaxically injecting 6-OHDA into the right striatum. Baicalein was administered intraperitoneally 30 min before and 90 min after lesion induction. Animals received a further daily injection of baicalein for 3 consecutive days. Two weeks after 6-OHDA injection, contralateral rotational asymmetry was observed by apomorphine challenge in lesioned mice. Tyrosine hydroxylase (TH) immunohistochemistry revealed a significant loss of terminals in lesioned striatum and the reduction of the numbers of TH-positive cell in the ipsilateral substantia nigra (SN). In addition, the levels of dopamine (DA) and DA metabolites were reduced and lipid peroxidation was increased in lesioned striatum. However, baicalein treatment reduced apomorphine-induced rotational behavior in 6-OHDA-lesioned mice, and increased TH immunoreactivity in the striatum and SN, and DA levels in lesioned striatum. Lipid peroxidation induced by 6-OHDA was also inhibited by baicalein treatment. Furthermore, when SH-SY5Y human neuroblastoma cells were treated with baicalein, 6-OHDA-induced cytotoxicity and reactive oxygen species (ROS) production were significantly reduced. These results indicate that baicalein effectively protects 6-OHDA-induced neuronal damage through antioxidant action.

Effecet of intrathecal injection of 6-OHDA or ?_1-adrenoceptor antagonist on the spinal analgesia of ketamine / 中国药理学通报

Aim To investigate the relationship between spinal cord noradrenergic neurons ? 1 adrenoceptors and the spinal analgesia of ketamine. Methods Kunming mice were used. Analgesia tests were investigated with warm water tail flick test. The effects of intrathecal injection (ith) of ketamine (50,100,200 ?g)on tail flick latency of animals were observed. And the effect of pretreatment with intrathecal 6 hydrodoapa(6 OHDA, 6?g ) and ? 1 adrenoceptor antagonist prazosin (5, 15 ?g) or terazosin (5, 15 ?g) , respectively on the spinal analgesia of ketamine (100 ?g,ith) was studied. Results Dose dependent analgesia was observed following ith ketamine (100,200 ?g, P

The effects of overexpression of Nurr1 on vulnerability of SK-N-SH cells to neurotoxin 6-OHDA / 中国药理学通报

Aim To investigate whether Nurr1 gene,a member of the nuclear receptor superfamily of transcription factors,contributed to 6-OHDA-induced DAergic neurons insults by comparing the effect of 6OHDA on neuroblastoma cells SK-N-SH and SK-N-SH cells overexpressing Nurr1gene(SK-N-SH/Nurr1).Methods The effect of Nurr1 gene on cell proliferation of SK-N-SH cells was investigated,then SK-N-SH and SK-N-SH/Nurr1 cells were exposed to 6-OHDA(5～100 ?mol?L~(-1))for 1～24 h,cells' morphology was observed under phase-contrast microscope.The cells viability was analyzed via MTT assay.Apoptosis was detected using Hoechst33342 staining.Results The Nurr1-overexpressing SK-N-SH cells showed significantly slow growth rate compared with that of SK-N-SH cells.Treatment with 50 ?mol?L~(-1) 6-OHDA changed SK-N-SH-Nurr1 cells' morphology within 1 h,accompanied by retraction of processes,shrinkage of cell body,whereas the morphology of SK-N-SH cells changed after treated with 50?mol?L~(-1) 6-OHDA for 2 h.The result of MTT assay indicated that exposure to 100 ?mol?L~(-1) 6-OHDA for 24 h induced a significant decrease in SK-N-SH/Nurr1 cells survival compared with SK-N-SH cells at various time points with an IC_(50) value of 75 ?mol?L~(-1) and 50 ?mol?L~(-1) respectively in SK-N-SH and SK-N-SH/Nurr1 cells.The evidence that treatment with 75 ?mol?L~(-1) 6-OHDA for 12 h induced typical apoptosis in SK-N-SH/Nurr1 cells was found in morphological features provided by Hoechst33342 staining,including chromatin condensation and nuclear fragmentation,and the percentages of apoptosis in SK-N-SH/Nurr1 cells was about 22%～24%.In contrast,no morphological characteristics of apoptosis in SK-N-SH cells were observed.Conclusions The present study suggests that Nurr1 gene renders SK-N-SH cells more vulnerable to neurotoxic insults. The mechanism of such action is probanly that normal Nurr1 gene function can stimulate apoptotic pathway induced by 6-OHDA,and play a major role in the high sensitivity of DArgic neurons to 6-OHDA insults as a vulnerable factor.

Cytotoxic Effect of 6-OHDA on the Dopaminergic Neurons and Astrocytes in the Dorsal Raphe Nucleus of the Rat / 대한해부학회지

This study was designed to clarify the cytotoxic effects of 6-hydroxydopamine (6-OHDA) on the dopaminergic neurons and astrocytes in the dorsal raphe nucleus (DRN), and to investigate neurodegenerative changes by immuno-histochemistry. Adult male rats (Sprague-Dawley strain) weighing from 250 to 350 g were used as experimental animals. 6-OHDA (100 micrometer dissolved in 0.1% ascorbic acid) was injected into the lateral ventricle of the rat brain with the Hamilton syringe. The control rats were treated with the similar volume of 0.1 % ascorbic acid. The rats were sacrificed at the 3rd, 5th, 10th and 20th day, respectively, after the injection of 6-OHDA. The cytotoxicity of 6-OHDA resulted in severe neurodegeneration of the dopaminergic neurons in the DRN. In the 3rd day, the dopaminergic fibers were dilated. In the 5th and 10th days, the dopaminergic fibers were depleted, and dopaminergic cell bodies were shrunken. In the 20th day, the dopaminergic cell bodies were almost completely disappeared. Astroglial reactions induced by 6-OHDA were also observed in the DRN. In the 5th day, astrocytes were significantly increased as compared with that of the control value. The value were reached at its maximum by the 20th day. Based on the present results, it suggests that 6-OHDA may act as a specific neurotoxin to dopaminergic neurons in the DRN, and induce severe neurodegenerative changes. Also, it suggests that the astroglial reaction in the DRN is gradually activated during the neurodegerative changes.

Effect of Ritanserin on the Circling Movement in the Unilateral Substantia Nigra-Lesioned Rats / 대한정신약물학회지

OBJECTIVE: Recently, the serotonin-dopamine interaction is being regarded as a possible mechanism for both less extrapyramidal symptoms and good therapeutic effect on negative symptoms which are outstanding advantages of atypical antipsychotics. The goal of the study was to further define serotonin dopamine interaction in three different brain area of rats ; prefrontal cortex, striatum and nucleus accumbens. METHOD: The rats used in this study weighed 150-300gm. Under the aesthesia with pentothal sodium(25 mg/kg), stainless steel cannula was inserted in the right substantia nigra according to atlas(Paxinous and Watson) and 6-OHDA was injected at the rate of 1 mul/min to make a unilateral substantia nigra lesion. A week later, apomorphine (s. c. 0.1 mg/kg) was injected through the cannula and the rats with circling behavior counting more than 200 for an hour were selected for the study. Three weeks after that, the rats were further divided into 3 groups according to the brain area that permanent stainless steel cannula was implanted : prefrontal cortex group, striatum group and nucleus accumbens group. Within each group comparison was done between the number of circling behavior obtained by the injection of vehicle plus apomorphine and the one obtained by the injection of ritanserin plus apomorphine. Wilcoxon signed ranks test was used in data-analysis. RESULTS: The effect of ritanserin on the circling behavior in prefrontal cortex was absent but in striatum and nucleus accumbens, increasing effect was noted. CONCLUSIONS: It might be suggested that serotonin has an inhibitory control on dopaminergic function in striatum and nucleus accumbens.