Acrylonitrile ; poisoning ; Acute Disease ; Adult ; Humans ; Male ; Parkinsonian Disorders ; chemically induced

Parkinson's disease (PD) is a multifactorial disorder of the nervous system where a progressive loss of dopaminergic neurons exist. However, the pathogenesis of PD remains undefined, which becomes the main limitation for the development of clinical PD treatment. Demethylenetetrahydroberberine (DMTHB) is a novel derivative of natural product berberine. This study was aimed to explore the neuroprotective effects and pharmacological mechanism of DMTHB on Parkinson's disease using C57BL/6 mice. A PD model of mice was induced by administration of MPTP (20 mg·kg^-1) and probenecid (200 mg·kg^-1) twice per week for five weeks. The mice were administered with DMTHB daily by gavage at the dose of 5 and 50 mg·kg^-1 for one- week prophylactic treatment and five-week theraputic treatment. The therapeutic effects of DMTHB were evaluated by behavior tests (the open field, rotarod and pole tests), immunohistochemical staining of tyrosine hydroxylase (TH), Nissl staining and biochemical assays. The molecular mechanisms of DMTHB on the key biomarkers of PD pathological states were analyzed by Western blot (WB) and qRT-PCR. DMTHB treatment alleviated the behavioral disorder induced by MPTP-probenecid. Nissl staining and TH staining showed that the damage of dopaminergic neurons in the substantia nigra was remarkably suppressed by DMTHB treatment. Western blot results showed that the ratio of Bcl-2/Bax and TH increased, but the level of α-synuclein (α-syn) was remarkably reduced, which indicated that the apoptosis of dopaminergic neurons in mice was significantly reduced. The protein phosphorylation of p-PI3K, p-AKT and p-mTOR also increased about 2-fold, compared with the model group. Furthermore, qRT-PCR results demonstrated that the mRNA levels of pro-inflammatory cytokines, IL-1β and TNF-α, were reduced, but the level of anti-inflammatory cytokine IL-10 increased after DMTHB treatment. Finally, the cellular assay displayed that DMTHB was also a strong antioxidant to protect neuron cell line PC12 by scavenging ROS. In this study, we demonstrated DMTHB alleviates the behavioral disorder and protects dopaminergic neurons through multiple-target effects includubg anti-apoptotic, anti-inflammatory and antioxidant effects.
Animals ; Dopaminergic Neurons/pathology* ; Mice ; Mice, Inbred C57BL ; Parkinson Disease/pathology* ; Parkinsonian Disorders/chemically induced* ; Substantia Nigra

The purpose of this article was to provide a literature review of occupational neurological disorders and related research in Korea, focusing on chemical hazards. We reviewed occupational neurological disorders investigated by the Occupational Safety and Health Research Institute of Korean Occupational Safety and Health Agency between 1992 and 2009, categorizing them as neurological disorders of the central nervous system (CNS), of the peripheral nervous system (PNS) or as neurodegenerative disorders. We also examined peer-reviewed journal articles related to neurotoxicology, published from 1984 to 2009. Outbreaks of occupational neurological disorder of the CNS due to inorganic mercury and carbon disulfide poisoning had helped prompt the development of the occupational safety and health system of Korea. Other major neurological disorders of the CNS included methyl bromide intoxication and chronic toxic encephalopathy. Most of the PNS disorders were n-hexane-induced peripheral neuritis, reported from the electronics industry. Reports of manganese-induced Parkinsonism resulted in the introduction of neuroimaging techniques to occupational medicine. Since the late 1990s, the direction of research has been moving toward degenerative disorder and early effect of neurotoxicity. To understand the early effects of neurotoxic chemicals in the preclinical stage, more follow-up studies of a longer duration are necessary.
Adolescent ; Adult ; Central Nervous System Diseases/chemically induced/epidemiology ; Female ; Humans ; Male ; Middle Aged ; Nervous System Diseases/chemically induced/*epidemiology/etiology ; Neurodegenerative Diseases/chemically induced/epidemiology ; Neurotoxicity Syndromes/*epidemiology/*etiology ; Occupational Diseases/chemically induced/*epidemiology/etiology ; Parkinsonian Disorders/chemically induced/epidemiology ; Peripheral Nervous System Diseases/chemically induced/epidemiology ; Republic of Korea

OBJECTIVETo investigate the changes in the firing activity of noradrenergic neurons in the locus coeruleus (LC) in a rat model of Parkinson disease (PD).

METHODS2 and 4 weeks after unilateral lesion of the nigrostriatal pathway in the rat by local injection of 6-hydroxydopamine (6-OHDA) into the right substantia nigra pars compacta (SNc), the firing activity of noradrenergic neurons in LC was recorded by extracellular single unit recording.

RESULTSThe firing rate of LC noradrenergic neurons increased significantly 2 and 4 weeks after 6-OHDA lesions compared to normal rats, respectively (P < 0.05). The percentage of irregularly firing neurons was obviously higher than that of normal rats during the fourth week after SNc lesion (P < 0.05).

CONCLUSIONLC noradrenergic neurons are overactive and more irregular in 6-OHDA-lesioned rats. These changes suggest an implication of the LC in the pathophysiological mechanism of PD.

Action Potentials ; physiology ; Animals ; Disease Models, Animal ; Locus Coeruleus ; pathology ; Male ; Neurons ; physiology ; Norepinephrine ; metabolism ; Oxidopamine ; Parkinsonian Disorders ; chemically induced ; pathology ; Rats ; Rats, Sprague-Dawley ; Time Factors

Animals ; Disease Progression ; Dopaminergic Neurons ; physiology ; Free Radical Scavengers ; blood ; Hydroxyl Radical ; antagonists & inhibitors ; Male ; Oxidopamine ; Parkinsonian Disorders ; blood ; chemically induced ; physiopathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the effects of exposure of paraquat and maneb on the behavior, the morphology and electrical activity of the Substantia nigra and striatum, and to discuss the relationship between this two pesticides and Parkinson's disease.

METHODS37 rats were divided randomly into 3 groups: control group (n = 11), paraquat (10 mg/kg) group (n = 13) and combinative group of paraquat (10 mg/kg) and maneb (30 mg/kg) (n = 13), and were exposed twice a week for 6 weeks by intraperitoneal injection. The behavior of animals in the declined-plane, the vertical-grid and the open-field test were observed. The morphology of substantia nigral neurons were investigated by HE pathology. The spontaneous discharge of striatum neurons were recorded after exposure.

RESULTSCompared to the control group and the pre-exposure group, both the numbers of animals sliding down from the declined-plane and the latency of rats' moving on the vertical-grid significantly increased, and the animals' autonomic movement decreased significantly (P < 0.05, P < 0.001). After the combinative exposure, the neurons of the Substantial nigra pars compacta (SNPc) were progressively impaired, the cell density of the paraquat group [(82.17 ± 12.91) n/mm(2)] and the combined group [(41.15 ± 6.44) n/mm(2)] were lower than that in control group (143.10 ± 20.85 n/mm(2)] (P < 0.01). In the paraquat group (5.97 ± 7.30 Hz) and the combined group [(6.95 ± 9.87) Hz], the average discharge rates of the striatum neurons were increased significantly compared to the control group [(1.78 ± 5.05) Hz] (P < 0.01). The bursting discharge was increased significantly in the combined group (22.3%) compared to the control group (9.8%) and the paraquat group (5.6%) (P < 0.05, P < 0.01).

CONCLUSIONThe co-exposure of paraquat and maneb could induce similar symptoms to Parkinsonism syndrome of rats such as rigidity, moving reduction and etc, and the combined exposure had a certain enhanced effect compared to alone paraquat exposure. The combinative exposure of paraquat and maneb could cause neural loss in SNPc and it is involved with the enhanced electrophysiological activity in striatum. The synergy toxicity of paraquat and maneb in nigrostriatal system is related to Parkinson's disease.

Animals ; Corpus Striatum ; drug effects ; Male ; Maneb ; toxicity ; Paraquat ; toxicity ; Parkinsonian Disorders ; chemically induced ; Pesticides ; toxicity ; Rats ; Rats, Sprague-Dawley ; Substantia Nigra ; drug effects

OBJECTIVETo study the changes in the expression of divalent metal transporter 1 (DMT1) and ferroportin 1 (FP1) in the substantia nigra (SN) of rats with manganese-induced parkinsonism.

METHODSEighty Sprague-Dawley rats were randomly divided into four groups. Rats in the control group were injected intraperitoneally with saline solution. Rats in the low-dose, medium-dose, and high-dose groups were injected intraperitoneally with 5, 15, and 20 mg/kg MnC12 solution, respectively, for 16 weeks. Three behavioral tests were performed at the 16th week. The concentration of Mn2+ in the SN was determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES), and the positive expression of tyrosine hydroxylase (TH) was measured by immunohistochemical staining to determine whether rats with manganese-induced parkinsonism were successfully produced. The expression of DMT1 and FP1 in SN was measured by immunohistochemical staining and fluorescent quantitative polymerase chain reaction.

RESULTSRats with manganese-induced parkinsonism were successfully produced using the above method. Compared with that in the control group, the concentrations of Mn2+ in the SN of rats exposed to 5, 15, and 20 mg/kg Mn2+ were significantly higher (1.72?0.33 vs 0.56 ± 0.20 µg/g, P<0.01; 2.92±0.77 vs 0.56±0.20 µg/g, P<0.01; 5.65±1.60 vs 0.56±0.20 µg/g, P<0.01). The mean ODs of TH-positive cells in the SN of rats exposed to 5, 15, and 20 mg/kg Mn+ were significantly lower than that in the control group (0.054±0.008 vs 0.109±0.019, P<0.01; 0.016±0.004 vs 0.109±0.019, P<0.01; 0.003±0.001 vs 0.109±0.019, P<0.01). Compared with that in the control group, the mean optical densities (ODs) of DMT1-positive cells in the SN of rats exposed to 15, and 20 mg/kg Mn2+ were significantly higher (0.062±0.004 vs 0.015±0.007, P<0.01; 0.116±0.064 vs 0.015±0.007, P<0.01). The mean ODs of FP1-positive cells in the SN of rats exposed to 5, 15, and 20 mg/kg Mn2+ were significantly lower than that in the control group (0.092±0.011 vs 0.306±0.081, P<0.01; 0.048±0.008 vs 0.306±0.081, P<0.01; 0.008±0.002 vs 0.306±0.081, P< 0.01). Rats exposed to 15 and 20 mg/kg Mn2+ had significantly higher expression of DMT1 mRNA in the SN than those in the control group (0.052±0.0126 vs 0.001±0.0004, P<0.05; 0.124±0.0299 vs 0.001±0.0004, P<0.05). However, rats exposed to 5, 15, and 20 mg/kg Mn2 had significantly lower expression of FP1 mRNA in the SN than those in the control group (0.059±0.0076 vs 0.162±0.0463, P<0.05; 0.033±0.0094 vs 0.162±0.0463, P< 0.05; 0.002±0.0007 vs 0.162±0.0463, P<0.05).

CONCLUSIONThe increased expression of DMT1 and reduced expression of FP1 may be involved in the processes of Mn2+ accumulation in the SN and dopaminergic neuron loss in rats with manganese-induced parkinsonism.

Animals ; Cation Transport Proteins ; metabolism ; Disease Models, Animal ; Manganese ; adverse effects ; Parkinsonian Disorders ; chemically induced ; metabolism ; RNA, Messenger ; Rats ; Rats, Sprague-Dawley ; Substantia Nigra ; metabolism ; physiopathology

Epidemiological studies have suggested an association between pesticide exposure and Parkinson's disease. In this study, we examined the neurotoxicity of an organochlorine pesticide, heptachlor, in vitro and in vivo. In cultured SH-SY5Y cells, heptachlor induced mitochondria-mediated apoptosis. When injected into mice intraperitoneally on a subchronic schedule, heptachlor induced selective loss of dopaminergic neurons in the substantia nigra pars compacta. In addition, the heptachlor injection induced gliosis of microglia and astrocytes selectively in the ventral midbrain area. When the general locomotor activities were monitored by open field test, the heptachlor injection did not induce any gross motor dysfunction. However, the compound induced Parkinsonism-like movement deficits when assessed by a gait and a pole test. These results suggest that heptachlor can induce Parkinson's disease-related neurotoxicities in vivo.
Animals ; *Apoptosis ; Astrocytes/drug effects/pathology ; Cell Line, Tumor ; Cells, Cultured ; Dopaminergic Neurons/*drug effects/pathology ; Gait ; Heptachlor/*toxicity ; Humans ; *Locomotion ; Mice ; Neurotoxicity Syndromes/etiology/physiopathology ; Parkinsonian Disorders/chemically induced ; Pesticides/*toxicity ; Substantia Nigra/*drug effects/pathology/physiopathology

In the present study, changes in the neuronal activity of serotonergic neurons in the dorsal raphe nucleus (DRN) and the effect of the selective 5-HT(1A) receptor antagonist WAY-100635 in a rat model of Parkinson's disease (PD) were investigated by using extracellular single unit recording. Rat model of PD was produced by microinjection of 6-hydroxydopamine (6-OHDA) into the substantia nigra pars compacta on the right side of the brain. The results showed that the mean spontaneous firing rate of DRN serotonergic neurons in the control and 6-OHDA-lesioned rats were (1.76+/-0.11) spikes/s (n=24) and (2.43+/-0.17) spikes/s (n=21), respectively. The firing rate of serotonergic neurons in 6-OHDA-lesioned rats was significantly higher than that in the control rats (P<0.001). In the control rats, 92% (22/24) of the neurons fired regularly and 8% (2/24) fired in bursts. In rats with 6-OHDA lesions, 9% (2/21) of neurons fired regularly, 43% (9/21) exhibited irregular pattern and 48% (10/21) fired in bursts. The percentage of DRN serotonergic neurons firing in bursts was obviously higher in 6-OHDA-lesioned rats than that in the control rats (P<0.001). Local injection of WAY-100635 (3 microg in 200 nL) into the DRN significantly increased the firing rate of serotonergic neurons with no change in firing pattern in the control rats (n=19, P<0.002), but did not change the firing rate and firing pattern of serotonergic neurons in 6-OHDA-lesioned rats (n=17, P>0.05). These results suggest the dysfunction of 5-HT(1A) receptor in 6-OHDA-lesioned rats and the involvement of the DRN in the pathophysiological mechanism of PD.
Action Potentials ; physiology ; Animals ; Disease Models, Animal ; Male ; Neurons ; physiology ; Oxidopamine ; Parkinsonian Disorders ; chemically induced ; physiopathology ; Piperazines ; pharmacology ; Pyridines ; pharmacology ; Raphe Nuclei ; physiopathology ; Rats ; Rats, Sprague-Dawley ; Serotonin ; metabolism ; Serotonin Antagonists ; pharmacology

BACKGROUNDHuman amniotic epithelial cells (HAECs) are able to secrete biologically active neurotrophins such as brain-derived neurotrophic factor and neurotrophin-3, both of which exhibit trophic activities on dopamine neurons. Previous study showed that when human amniotic epithelial cells were transplanted into the striatum of 6-hydroxydopamine (6-OHDA)-induced Parkinson disease rats, the cells could survive and exert functional effects. The purpose of this study was to investigate the survival and the differentiation of human amniotic epithelial cells after being transplanted into the lateral ventricle of Parkinson's disease (PD) rats, and to investigate the effects of grafts on healing PD in models.

METHODSThe Parkinson's model was made with stereotactic microinjection of 6-hydroxydopamine (6-OHDA) into the striatum of a rat. The PD models were divided into two groups: the HAECs group and the normal saline (NS) group. Some untreated rats were taken as the control. The rotational asymmetry induced by apomorphine of the HAECs group and the NS group were measured post cell transplantation. The expression of nestin and vimentin in grafts were determined by immunohistology. Ten weeks after transplantation the density of tyrosine hydroxylase positive cells in the substantia nigra of the HAECs group, NS group and the untreated group was determined. The differentiation of grafts was determined by TH immunohistology. High performance liquid chromatography (HPLC) was used to determine monoamine neurotransmitter levels in the striatum.

RESULTSThe rotational asymmetry induced by apomorphine of the HAECs group was ameliorated significantly compared to the NS group two weeks after transplantation (P < 0.01). The grafts expressed nestin and vimentin five weeks after transplantation. TH immunohistochemistry indicated that the TH positive cells in the substantia nigra of the HAECs group increased significantly compared to the NS group (P < 0.01). Tyrosine hydroxylase (TH) positive cells in the substantia nigra of the HAEC group and the NS group were decreased compared to the untreated group (P < 0.01). Dopamine and DOPAC levels in the striatum of the HAECs group increased significantly compared to the NS group (P < 0.05). Homovanillic acid (HVA) levels in the striatum of the HAECs group increased significantly compared to the NS group (P < 0.01). In addition dopamine, DOPAC, and HVA levels in the striatum and dopamine levels in the cerebrospinal fluid of the HAECs group and the NS group were decreased compared to the untreated group (P < 0.05).

CONCLUSIONSHuman amniotic epithelial cells could be used to ameliorate the rotational asymmetry induced by apomorphine of the PD models. This could have been due to the increased content of dopamine and its metabolic products, DOPAC and HVA, in the striatum in the PD models.

Amnion ; cytology ; Animals ; Apomorphine ; pharmacology ; Chromatography, High Pressure Liquid ; Epithelial Cells ; cytology ; drug effects ; transplantation ; Female ; Homovanillic Acid ; metabolism ; Humans ; Immunohistochemistry ; Oxidopamine ; toxicity ; Parkinsonian Disorders ; chemically induced ; metabolism ; therapy ; Rats ; Rats, Sprague-Dawley