Parkinson's Disease Model Group Research Articles

The involvement of Slc7a11/xCT related iron accumulation on acupuncture intervention in 6-OHDA-induced Parkinson rat

BackgroundAcupuncture plays a critical role for the treatment of patients with Parkinson's disease (PD), which is characterized by ferroptosis of dopaminergic neurons. It has been found that acupuncture can reduce iron accumulation. However, the mechanism of acupuncture therapy against PD by inhibiting ferroptosis remains unclear. ObjectiveTo investigate the potential mechanism of acupuncture on alleviating ferroptosis in 6-OHDA-induced PD rats. MethodsMale Sprague-Dawley rats were randomly divided into sham group, acupuncture group, and PD model group, with the PD model induced by 6-OHDA. The motor function of the rats was tested by the rotation test and suspension test, respectively. Immunohistochemistry and iron staining were performed to analyze nerve damage, and the effect of acupuncture on the accumulation of iron in the substantia nigra (SN). RNA-seq analysis in the SN of rats were performed to discover ferroptosis-related genes. Differentially expressed genes (DEGs) resulted from the acupuncture treatment were identified and were used for Gene Ontology (GO) function, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. A protein–protein interaction (PPI) network was constructed, and alternative splicing (AS) analysis of the transcriptome was performed. Western blot was used to detect the protein level change of Slc7a11/xCT. ResultsRotation test and suspension test indicated a positive effect of acupuncture on body weight gain and limb function. Perl's iron staining and ELISA test detected 6-OHDA induced iron accumulation in the SN and nerve damage, which was mitigated by acupuncture treatment. Acupuncture treatment brought about the differential expression of a total of 1088 genes in the SN of rats. GO and KEGG enrichment revealed that such DEGs were mainly associated with several key biological process (BP), cellular component (CC) and molecular function (MF) terms. These terms included collagen fibril organization, extracellular matrix organization, collagen trimer, extracellular matrix components, chemokine receptor binding and cargo receptor activity, etc. Additionally, the DEGs were found to be involved in pathways such as complement and coagulation. The PPI network of DEGs suggested a critical role of Slc7a11, which was further supported by an up-regulated Slc7a11/xCT protein level in the substantia nigra (SN) tissue of rats treated with acupuncture compared to their PD model counterparts (P = 0.045). ConclusionAcupuncture may prevent ferroptosis through Slc7a11/xCT as one of the targets in 6-OHDA-induced PD model and thereby could be promising for PD treatment.

Bmal1 mediates the neuroprotective effect of sodium butyrate in a mouse model of Parkinson's disease

To investigate the mechanisms that mediate the neuroprotective effect of the intestinal microbial metabolite sodium butyrate (NaB) in a mouse model of Parkinson's disease (PD) via the gut-brain axis. Thirty-nine 7-week-old male C57BL/6J mice were randomized equally into control group, PD model group, and NaB treatment group. In the latter two groups, PD models were established by intraperitoneal injection of 30 mg/kg 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) once daily for 5 consecutive days, and normal saline was injected in the control group. After modeling, the mice received daily gavage of NaB (300 mg/kg) or an equal volume of saline for 14 days. Behavioral tests were carried out to assess the changes in motor function of the mice, and Western blotting was performed to detect the expressions of tyrosine hydroxylase (TH) and α-synuclein (α-syn) in the striatum and nuclear factor-κB (NF-κB), tumor necrosis factor (TNF-α), interleukin 6 (IL-6), and the tight junction proteins ZO-1, Occludin, and Claudinin the colon. HE staining was used to observe inflammatory cell infiltration in the colon of the mice. RNA sequencing analysis was performed to identify the differentially expressed genes in mouse colon tissues, and their expressions were verified using qRT-PCR and Western blotting. The mouse models of PD with NaB treatment showed significantly increased movement speed and pulling strength of the limbs with obviously upregulated expressions of TH, Occludin, and Claudin and downregulated expressions of α-syn, NF-κB, TNF-α, and IL-6 (all P < 0.05). HE staining showed that NaB treatment significantly ameliorated inflammatory cell infiltration in the colon of the PD mice. RNA sequencing suggested that Bmal1 gene probably mediated the neuroprotective effect of NaB in PD mice (P < 0.05). NaB can improve motor dysfunction, reduce dopaminergic neuron loss in the striatum, and ameliorate colonic inflammation in PD mice possibly through a mechanism involving Bmal1.

Effect of electroacupuncture on Nrf2/NLRP3/Caspase-1 pathway mediated-pyroptosis in mice with Parkinson's disease.

To observe the effect of electroacupuncture (EA) on nuclear transcription factor E2 related factor 2 (Nrf2)/NOD-like receptor family pyrin domain-containing protein 3 (NLRP3)/cysteine aspartic acid specific protease-1 (Caspase-1) pathway in the substantia nigra (SN) of mice with Parkinson's disease (PD), so as to explore the neuroprotective mechanism of EA. Forty C57BL/6 male mice were randomly divided into 4 groups, namely, control, PD model, EA and sham-EA groups, with 10 mice in each group. The PD mouse model was established by gavage of rotenone for 4 weeks. Mice in the EA group were given EA stimulation (1 mA, 2 Hz) at "Fengfu" (GV36), bilateral "Taichong" (LR3) and "Zusanli" (ST36) for 30 min, once daily for 2 consecutive weeks. And mice in the sham-EA group were given acupuncture at the subcutaneous areas of the same acupoints without EA stimulation. The open-field test was used for assessment of mouse behavior. The levels of interleukin-1β (IL-1β) and interleukin-18 (IL-18) in the serum were detected by enzyme-linked immunosorbent assay . The positive expression of tyrosine hydroxylase (TH) in SN was determined by immunohistochemistry. The mRNA expression levels of Nrf2, NLRP3, Caspase-1, gasdermin D(GSDMD), IL-1β, IL-18 and the protein expression levels of Nrf2, NLRP3, Caspase-1 and GSDMD in the SN were detected by quantitative real-time PCR and Western blot, separately. After modeling, compared with the control group, the behavioral score was increased (P<0.01), the total exercise time, the total distance and the average speed were decreased (P<0.01), and the positive expression of TH and the mRNA and protein expression levels of Nrf2 in the SN were decreased (P<0.01), while the contents of IL-1β and IL-18 in serum, the mRNA and protein expression levels of NLRP3, Caspase-1 and GSDMD and the mRNA expression levels of IL-1β and IL-18 in the SN were up-regulated (P<0.01) in the PD model group. Following EA intervention, the behavioral score was decreased(P<0.01), the total exercise time, total distance and average speed were increased (P<0.01), the positive expression of TH and the mRNA and protein expressions of Nrf2 in SN were up-regulated (P<0.01, P<0.05), while the contents of IL-1β and IL-18 in serum, the mRNA and protein expression levels of NLRP3, Caspase-1 and GSDMD as well as the mRNA expression levels of IL-1β and IL-18 in the SN were down-regulated (P<0.01, P<0.05) in the EA group relative to the PD model and sham-EA groups. There were no significant differences in the above indicators between the PD model and sham-EA groups. EA stimulation of GV36, LR3 and ST36 can improve motor deficits, reduce the loss of dopamine neurons in the SN, and inhibit neuroinflammatory responses in mice with PD, which may be related to its effects in regulating the Nrf2/NLRP3/Caspase-1 pathway mediated pyroptosis.

Dihydromyricetin alleviates pyroptosis and necroptosis in mice with MPTP-induced chronic Parkinson's disease by inducing autophagy

To investigate the effect of 8-week dihydromyricetin (DHM) treatment on motor ability of mice with MPTP/probenecid-induced Parkinson's disease (PD) and explore the molecular mechanism. Sixty C57BL/6 mice were randomized into the control group, PD model group, PD+DHM group and PD+NEC-1 group (n=15). In the latter 3 groups, the mice were treated with 25 mg·kg-1·d-1 MPTP and 250 mg·kg-1·d-1 probenecid twice a week for 5 weeks to establish PD models; DHM (100 mg·kg-1·d-1) was administered 5 times a week via gavage for 8 weeks and NEC-1 (6.25 mg·kg-1·d-1, twice a week) via intraperitoneal injection for 5 weeks. The changes in motor function of the mice were assessed, and the expressions of TH, GFAP and Iba-1 in the substantia nigra were detected with immunofluorescence assay; serum levels of IL-1β and LDH were detected using ELISA. The mRNA expressions of TNF-α and IL-6 were determined with RT-PCR, and the expressions of TH and proteins associated with pyroptosis, neuroinflammation, necroptosis and autophagy in the striatum were detected using Western blotting. MPP +-activated Bv-2 cells were treated with different concentrations of DHM or 3-MA, and the expressions of proteins associated with autophagy and NLRP3 were detected using Western blotting; PI staining was used to detect cell necroptosis. The PD mouse models showed significantly reduced TH-positive cells and TH protein expression (P < 0.001). DHM obviously ameliorated motor deficits and TH loss in PD mice, increased TH expression (P=0.0023), decreased α-syn levels (P < 0.001), lowered the protein expressions of GFAP (P=0.045) and Iba-1 (P < 0.001) and the mRNA and protein levels of TNF-α (P=0.0015) and IL-6 (P < 0.001), and increased IL-4 level (P < 0.001). The 8-week DHM treatment significantly suppressed pyroptosis and necroptosis and activated autophagy in the striatum of the PD mice. In MPP +-induced Bv-2 cells, DHM treatment effectively reversed autophagy impairment and inhibited NLRP3 and TNF-α, IL-6 and IL-1β release, and the anti--inflammatory effects of DHM was obviously blunted by 3-MA. DHM can improve motor function of PD mice probably by activating autophagy to inhibit pyroptosis and necroptosis and reduce neuroinflammation.

The Effect of Forced Exercise on Striatal and Serum Serotonin Levels in a Parkinson’s Mouse Model

Objective: The general treatment approach for Parkinson's disease (PD) is L-dopa administration. While L-dopa only relieves dopaminergic deficiency, it has no effect on the serotonergic system, which is thought to be impaired in the disease. The limitations of current treatment methods have made it necessary to discover new approaches to the treatment of the disease. Studies conducted in recent years report that different types of exercises applied lead to improvement in the symptoms of PD. Exercising decreases serotonin levels and increases dopamine levels. However, the effect of exercise on serotonin levels together with dopamine in PD and its effect on non-motor symptoms such as anxiety and depression are unknown.&#x0D; Methods: PD is created using MPTP. The exercise groups were given challenging treadmill exercises for 6 weeks. Serotonin and dopamine levels were measured in the striatum and serum. Parkinson's symptoms were examined with pole test and behavioral tests.&#x0D; Results: Exercise significantly reduced bradykinesia, increased motor activity, and decreased anxiety behaviors in the exercise groups. While exercise increased striatal dopamine levels in all exercise groups, there was no difference in striatal serotonin levels. However, the serotonin serum level was decreased in the PD model group. While treadmill exercise increased striatal dopamine levels in the Parkinson's mouse model, it did not cause any change in striatal serotonin levels. However, the decrease in serum serotonin level was determined only in the MPTP group.&#x0D; Conclusion: The fact that the decrease in serotonin level was only in the disease group and the lower level of anxiety observed in behavioral experiments suggested that regular treadmill exercise was the reason. However, this improvement was not observed in cases where the anxiety level was very high.

Effects of Nardostachys jatamansi on gut microbiota of rats with Parkinson's disease

Under the guidance of the traditional Chinese medicine(TCM) theory of &quot;Zangfu-organs of spleen and stomach&quot; and the modern theory of &quot;microbiota-gut-brain axis&quot;, this study explored the effects of Nardostachys jatamansi on the gut microbiota of rats with Parkinson's disease(PD). The 40 SD rats were randomly divided into the control group, PD model group, levodopa group, and Nardostachys jatamansi ethanol extract group. The PD model was established by subcutaneous injection of rotenone in the neck and back area. After 14 days of intragastric administration, the PD rats' behaviors were analyzed through open field test, inclined plane test, and pole test. After the behavioral tests, the striatum, colon, and colon contents of rats in each group were collected. Western blot was employed to detect the protein expression of tyrosine hydroxylase(TH) and α-synuclein(α-syn) in striatum and that of α-syn in colon. Enzyme linked immunosorbent assay(ELISA) was used to detect the levels of tumor necrosis factor-α(TNF-α), interleukin-1β(IL-1β), and nuclear factor-kappa B(NF-κB) in striatum and colon. High-throughput sequencing of 16 S rRNA gene was conducted to detect the differences in microbial diversity, abundance, differential phyla, and dominant bacteria of rats between groups. The results indicated that Nar. ethanol extract could relieve dyskinesia, reverse the increased levels of α-syn, TNF-α, IL-1β, and NF-κB in striatum, and improve the protein expression of TH in striatum of PD rats. The α diversity analysis indicated a significant decrease in diversity and abundance of gut microbiota in the PD model. The results of linear discriminant analysis effect size(LEfSe) of dominant bacteria indicated that Nardostachys jatamansi ethanol extract increased the relative abundance of Clotridiaceae, Lachnospiraceae, and Anaerostipes, and reversed the increased relative abundance of Proteobacteria, Gammaproteobacteria, Enterobacteriaceae, and Escherichia-Shigella in PD model group to exhibit the neuroprotective effect. In summary, the results indicated that Nar. ethanol extract exert the therapeutic effect on PD rats. Specifically, the extract may regulate gut microbiota, decrease the levels of proinflammatory cytokines, and reduce the protein aggregation of α-syn in the colon and striatum to alleviate intestinal inflammation and neuroinflammation. This study provides a basis for combining the theory of &quot;Zangfu-organs of spleen and stomach&quot; with the theory of &quot;microbiota-gut-brain axis&quot; to treat PD.

Lipoic acid inhibits nerve cell apoptosis in rats with Parkinson's disease via Erk signaling pathway

Purpose: To investigate the effect of lipoic acid on nerve cell apoptosis in rats with Parkinson's disease via the extracellular signal-regulated kinase (ERK) signaling pathway.Methods: A total of 36 rats were randomly divided into normal group (n = 12), Parkinson's disease model group (n = 12) and lipoic acid group (n = 12). The neuronal morphology was examined by means of Nissl staining, while cell apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay.Results: The neurons were severely damaged in model group, while neuronal morphology and structure were ameliorated in lipoic acid group when compared with those in model group. The p-ERK was lowered significantly (p &lt; 0.05) in model group and lipoic acid group compared with that in normal group. Levels of mRNA, caspase-3 and Bax increased significantly, while Bcl-2 decreased in model group and lipoic acid group when compared with those in normal group (p &lt; 0.05). Lipoic acid treatment significantly reduced mRNA expression of caspase-3 and Bax, but increased Bcl-2 compared with model group. Furthermore, ELISA results indicate that model and lipoic acid groups exhibited raised caspase-3 and Bax but significantly reduced Bcl-2 levels, compared with normal group. The results also showed that the apoptosis was higher in the other two groups than in normal group; on the other hand, it was significantly lower in lipoic acid group than in model group (p &lt; 0.05).Conclusion: Lipoic acid inhibits nerve cell apoptosis in rats with Parkinson's disease by up-regulating ERK signaling pathway. Therefore, lipoic acid is a potential neuroprotective agent for the management of Parkinson’s disease.

Expression of nAChRα7 receptor in model rats with Parkinson’s disease dementia

To investigate the expression and role of nicotinic acetylcholine α7 subunit (nAChRα7) in the hippocampus of rats with Parkinson's disease (PD) and Parkinson's disease dementia (PDD). PD model was established with 6-hydroxydopa. Then, methyllycaconitine was further used to prepare a PDD model. The behavioral indexes and malondialdehyde (MDA) and superoxide dismutase (SOD) levels were measured. The mRNA level and protein level of nAChRα7 in hippocampus was detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western-blot, respectively. The α7nAchR and NeuN protein was detected by immunofluorescence. Compared with the PD model group, the escape latency of the PDD model group was significantly prolonged while the times of crossing platforms was significantly reduced (p < 0.05). The SOD level in the PDD and PD group decreased as compared with the control group (p < 0.05), while the MDA content increased (p < 0.05). The mRNA level and protein expression of nAChRα7 in the PDD and PD model group was significantly lower than that in the control group (p < 0.05). There was a significant difference in the nAChRα7 protein level between the PDD and PD model group (p < 0.05). Together, the nAChRα7 receptor level was significantly decreased in the PDD model group, indicating that the decrease in the nAChRα7 receptor levels is a possible mechanism of the pathogenesis of PDD.

Validation of an in vivo electrochemical immunosensing platform for simultaneous detection of multiple cytokines in Parkinson’s disease mice model

Parkinson's Disease (PD) is a neurodegenerative chronic disorder which destroys brain tissue and result in impaired movement. Early diagnosis of PD before the appearance of clinical symptom is vital for effective treatment. High levels of proinflammatory cytokines found in PD patient’s brains, as natural inflammation response product, are potential biomarkers for PD detection in the early stage. Herein, we developed an in vivo electrochemical immunosensing device based on glassy carbon rod to simultaneously detect three proinflammatory cytokines (IL-1β, IL-6 and TNF-α). The levels of IL-1β, IL-6 and TNF-α secreted by N2a cells significantly increased within 24 h after lipopolysaccharide (LPS) stimulation. Under in vivo conditions, the concentrations of IL-1β, IL-6 and TNF-α in PD model group achieved by injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intraperitoneally, were significantly higher than those in the control mouse group. The concentrations of three cytokines in vivo/vitro detected by this immunosensing device was comparable to that obtained by ELISA. Furthermore, this deployable immunosensing device was proved to be highly sensitive with the limits of detection (LODs) of 5 pg mL−1 for each cytokine, specific and reliable, suggesting its potential to be a universal immunosensing platform for early identification and diagnosis of PD in vivo in the future.

Chinese Herbal Complex ‘Bu Shen Jie Du Fang’ (BSJDF) Modulated Autophagy in an MPP+-Induced Cell Model of Parkinson’s Disease

Autophagy plays an important role in the development of Parkinson disease (PD). Previous studies showed that autophagy could protect cells from α-synuclein toxicity and promote functional coupling of mitochondria. But it is still a question whether modulating autophagy can be used to treat PD. In traditional Chinese medicine, a specific Chinese herbal complex called Bu Shen Jie Du Fang (BSJDF) has a long history of treating motor impairments similar to Parkinson disease, while its mechanism is still unclear. As a pilot study, we aimed to evaluate the efficacy and its mechanism of Bu Shen Jie Du Fang in an MPP+-induced cell model of Parkinson's disease. And the phase contrast microscope (PCM) revealed that the BSJDF group had the greatest surviving cell counts compared with all other treated cell groups except the normal group. And Cell Counting Kit 8 (CCK8) assays showed a similar result. In BSJDF group, 3.7 ×107 cells/dish was identified by hemocytometer counts, which was significantly higher than other groups except the normal cells (p<0.05). In the BSJDF group, autophagy can be observed by transmission electron microscopy (TEM). Protein expression of Atg12 and LC3 in the BSJDF group was upregulated compared to the PD model group (p<0.05). Atg12 mRNA expression was also upregulated in the BSJDF group (p<0.05). In conclusion, our study indicated that the therapeutic mechanisms of BSJDF may be mediated by stimulating autophagy, and modulating autophagy can be used to treat PD.

Transcriptome sequencing in a 6-hydroxydopamine rat model of Parkinson's disease.

The neurotoxin 6-hydroxydopamine (6-OHDA) has been widely exploited as a tool for modeling Parkinson's disease (PD) in the rat. This study aimed to provide a comprehensive profile of the mRNAs and long noncoding RNAs (lncRNAs) in rats treated with 6-OHDA as a model of PD. Female SPF Wistar rats were randomly divided into two groups: a PD model group and a control group. The PD model was induced by 6-OHDA injection. RNA-seq analysis was performed on 6-OHDA-treated rats and corresponding controls. Novel lncRNAs were identified. Differentially expressed genes (DEGs) and differentially expressed lncRNAs were identified in the PD group compared with controls. Gene Ontology function and pathway enrichment analyses were conducted on the DEGs, followed by construction of a protein-protein interaction (PPI) network. In addition, prediction of lncRNA target genes and function prediction of lncRNAs were performed. Moreover, microRNAs (miRNAs) that interacted with the DEGs and differentially expressed lncRNAs were predicted to construct a miRNA-lncRNA-mRNA regulatory network. A total of 536 DEGs and 512 differentially expressed lncRNAs (44 up-regulated and 10 down-regulated known lncRNAs; 407 up-regulated and 51 down-regulated novel lncRNAs) were identified in the PD rat model compared with controls. The DEGs and target genes of lncRNAs were mainly associated with the innate immune response, 2'-5'-oligoadenylate synthetase activity, GTPase activity, GTP binding and the RIG-I-like receptor signaling pathway. IRF7 and ISG15 were hub proteins in the PPI network. Many mRNAs and lncRNAs interacted with other molecules in a competing endogenous RNA network, such as MAS1, TMPRSS2, NPTX1, XLOC_016191, XLOC_026924 and XLOC_005439. We conclude that IRF7, ISG15, MAS1, TMPRSS2, NPTX1, XLOC_016191, XLOC_026924 and XLOC_005439 may contribute critical roles in the pathogenesis of PD.

Neuroprotective effects of paeonol in a cell model of Parkinson disease

To investigate the effects of paeonol on neuron cell model of Parkinson disease (PD). The cell model of Parkinson disease was induced by treatment of 1-Methyl-4-phenylpyridinium (MPP+) in PC12 cells, the PD model cells were treated with 1 μmol/L, 3 μmol/L or 9 μmol/L paeonol for 24h, respectively. Cell viability and LDH leakage were detected by MTT and lactate dehydrogenase (LDH) assay; the apoptosis of PC12 cells was assessed by Hoechst 33258 staining and flow cytometry; reactive oxygen species (ROS) production was detected by DCFH-DA method; and the ratio of Bax/Bcl-2 and activation of caspase-3 were determined by Western blotting. MPP+ treatment significantly reduced cell viability, increased LDH leakage, enhanced the proportion of apoptotic cells and ROS production. In addition, MPP+ treatment dramatically increased the Bax/Bcl-2 ratio, and the activation of caspase-3. Compared to PD model group, paeonol treatment significantly enhanced cell viability, decreased LDH leakage, inhibited the proportion of apoptotic cells and ROS production, reduced the Bax/Bcl-2 ratio and the activated caspase-3 protein. Paeonol can prevent PC12 cells from apoptosis induced by MPP+, and the mechanism may be associated with the down-regulation of ROS production, Bax/Bcl-2 ratio and Caspase-3 activation.

The effect of TrkA signaling pathway on the expressions of TRPC1，TRPC3 in 6-hydroxydopamine lesioned rat treated by electroacupuncture

Objective: We investigate the effect of TrkA signaling pathway on the expressions of transient receptor potential channel in 6-hydroxydopamine(6-OHDA) lesioned rat treated by electroacupuncture and to explore the role of trkA signaling pathway and TRP subfamily in the pathogenesis of Parkinson's disease (PD), which would reveals the mechanisms of electroacupuncture (EA) neuroprotective effect. Methods: The experimental models were established by unilateral injection of 6-OHDA into the left medial forebrain bundle (MFB).TrkA signaling pathway inhibitor K252a was infected into MFB through two small burr holes in the skull to block trkA signal.The change of TRPC1 and TRPC3 expressions was detected by use of immunohistochemistry and RT-PCR as well as TUNEL for cell apoptosis. Results: The expressions of TRPC1 and TRPC3 in the substantia nigra (SN) of the 6-OHDA lesioned rat were significantly reduced. Compared with PD model group, TRPC1 and TRPC3 expressions were significantly increased in the EA group. There was no statistically significance in TRPC1 and TRPC3 expressions between K252a and PD model groups ( P &gt; 0.05). The number of apoptotic cells in SN increased 54.5% in the PD model rats, while positive apoptotic cells were significantly reduced in the EA group. There was no statistically significance in apoptotic cells between K252a and PD model groups ( P &gt;0.05). Conclusion: TRPC1 and TRPC3 expressions downregulated in the SN of the 6-OHDA lesioned rat, which was accompanied by apoptosis increase in the SN. EA treatment could reverse this effect, and trkA signaling pathway inhibitors K252a can attenuate the neuroprotective effect of EA. It suggested that TRPC1 and TRPC3 may play an important role in the pathogenesis of PD, and certain TRPC subfamily expressions change may be associated with the pathogenesis of PD. Its expression might be subject to trkA signaling pathway, and this signal pathway may be the regulation target for EA neuroprotection.

Neural Pathway Interference by Retained Acupuncture: A Functional MRI Study of a Dog Model of Parkinson's Disease

The aims of this study were to investigate the interference of the brain activation during a passive movement task (PMT) by retained acupuncture at the ST 36 acupoint and to compare these effects between normal brain and Parkinson's disease (PD) brain. Functional magnetic resonance imaging (fMRI) techniques have been used to study neurophysiology in animals. Eight healthy beagle dogs were divided into two groups of four dogs each, a normal control group and a PD model group. PD was induced by intravenous injection of 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-HCl. During fMRI, the PMT was performed in the right tarsal joint during three different sessions, which consisted of PMT only, PMT while an acupuncture needle was inserted at the ST 36 acupoint, and PMT while needle was inserted at a sham point. Standard veterinary neurological examination was performed on dogs with MPTP-induced PD. A homogeneous grade similar to human PD patients was evident in all dogs. The fMRI study showed that insertion of the acupuncture needle at acupoint ST 36 significantly affected the proprioceptive brain activation by decreasing blood oxygenation level-dependent signal intensity in basal ganglia, limbic system, and cerebellum. Compared with normal and PD brain, we suggest that acupuncture at ST 36 has different modulation effects depending on the pathologic condition of the brain. The study provides evidence of the potential clinical applications of retained acupuncture at ST 36 for rehabilitation therapy of PD patients.

Efficacy of repetitive transcranial magnetic stimulation treatment with MPTP Parkinson's disease mice

Objective To observe the efficacy of the treatment of repetitive transcranial magnetic stimulation (rTMS) on the 1 ⁃ methyl ⁃ 4 ⁃ phenyl ⁃ 1, 2, 3, 6 ⁃ tetrahydropyridine (MPTP) mouse model of Parkinson's disease (PD). Methods Fifty⁃six C57BL/6J male mice were divided into 4 groups: PD model group, sham magnetic stimulation group (s⁃rTMS group), rTMS group and control group. Mice were given intraperitoneal injection of MPTP (15 mg/kg, every 2 h, 4 times) to prepare mouse model of Parkinson's disease 24 h before accepting repetitive transcranial magnetic stimulation. The stimulation were controlled at 1.00 Hz, 1.00 T, and lasted for 25 s, being performed at fixed time for 14 d. At the 1, 3, 7 and 14 d after MPTP injection, Rotarod Test were performed to evaluate physical coordination ability and freedom of movement of mice. Immunohistochemical staining was used in the midbrain and striatum to count the number of tyrosine hydroxylase (TH) ⁃ positive cells, and high ⁃ performance liquid chromatography ⁃ electrochemical detection (HPLC ⁃ ECD) of striatal dopamine content was applyed. Results The rotary number of mice in rTMS group（85.89±3.74）were significantly higher than that in PD group (59.71 ± 8.33; P = 0.000). TH⁃positive neurons of substantia nigra in rTMS group (36.67 ± 3.82) were significantly more than PD group (31.67 ± 3.35; P = 0.000). Dopamine concentration in striatum of PD group (152.35 ± 1.64) was significantly lower than that in rTMS group (258.70 ± 1.06; P = 0.000). Conclusion The repetitive transcranial magnetic stimulation could improve the motor coordination of MPTP mice and protect injured TH ⁃ positive neurons in substantia nigra and TH ⁃ positive nerve fibers in striatum, as well as elevating dopamine level in striatum. DOI：10.3969/j.issn.1672-6731.2011.01.014

SU‐GG‐J‐135: Exploring the Neuroprotective Effects of Bee Venom in a Mouse Parkinson Model with Immunohistochemistry, Magnetization Transfer Ratio Imaging and Spectroscopy

Purpose: Neuroprotective therapeutics stop or slowdown the degeneration process in animal models of Parkinson's disease (PD). In the present study, we investigated the anti‐inflammatory effect of bee venom (BV) on lipopolysaccharide (LPS)‐stimulated microglia. Method and Materials: To investigate whether MR techniques have added value in neuroprotection research in the MPTP mouse model, both MRI and MRS were applied to investigate the neuroprotective effects of BV. BV is suggested to stimulate anti‐inflammatory processing indirectly via DA‐dependent mechanisms or γ‐aminobutyric acid (GABA) and glutamate release. Magnetization transfer ratio (MTR) and 1H‐MRS studies were performed on control mice, MPTP‐intoxicated mice and BV treatment mice. The successfully induced lesions were verified by tyrosine hydroxylase immunolabelling on the substantia nigra (SN) and striatum (ST) performed on perchloric extracts of mice brains, after the control mice and the MPTP‐intoxicated mice were killed. All the MTR and 1H‐MRS experiments were performed on a 9.4 T MRI/MRS system using a standard head coil. Outer volume suppression combined with the ultra‐short echo‐time stimulated echo acquisition mode was used for the localized 1H‐MRS. The quantitative analysis of metabolites was determined using jMRUI from the 1H spectra obtained in vivo on the striatum. Results: The peak height of the MTR histograms in the PD model group was significantly lower than that in the BV treatment group (P&lt;0.05). The present study revealed that the peak height of the MTR histogram was significantly decreased in the ST and SN, and a significant increase of the Glx/Cr ratio was found in the striatum of the PD group, as compared with that of the BV treatment group. Conclusion: These results demonstrate that BV possess a potent suppressive effect on proinflammatory responses of microglia and suggest that these compounds may offer substantial therapeutic potential for treatment of neurodegenerative diseases that are accompanied by microglial activation.

Protective action of recombinant neurturin on dopaminergic neurons in substantia nigra in a Rhesus monkey model of Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disease characterized by muscular trembling palsy due to lack of dopamine (DA) in the substantia nigra-striatum (nigrostriatal) system resulting from the degeneration and necrosis of dopaminergic neurons. No effective cure has been found. Neurturin (NTN) has been demonstrated to act specifically on midbrain (mesencephalic) dopaminergic neurons with protective actions specifically. In the present study, we induced rhesus monkey model of Parkinson's disease by injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Rhesus monkeys were randomly divided into a PD model group, NTN treatment group and normal control groups. In the NTN treatment group, 1 mg of E. coli- derived recombinant human NTN was injected into the cerebral ventricles 48 h before the injection of MPTP. Results indicated that Rhesus monkeys in the PD model group acquired PD symptoms that increasingly aggravated over time, while monkeys treated with NTN had less apparent or no symptoms. Using fluorospectrophotometry, the dopamine (DA), 5, 5-hydroxytrytamine (5-HT) and the 5-hydroxyindoleacetic acid (5-HIAA) contents of DA, 5-HT and 5-HIAA in substantia nigra, putamen and caudate nucleus in monkeys from the model group was found to be significantly lower than in the normal control group. While no significant differences were found between monkeys treated with NTN and normal control groups, the contents of DA, 5-HT and 5-HIAA in the NTN treatment group were higher than those observed in the PD model group. A dramatic loss of neurons in the substantia nigra in monkeys in the PD model group was observed by light microscopy, while no obvious loss was observed in the NTN treatment group in which the numbers of neurons were similar to those in normal controls. These results indicate that recombinant human NTN can prevent PD symptoms as well as protect dopaminergic neurons and preserve DA content in midbrain substantia nigra in rhesus monkeys exposed to MPTP.