Effect of Achyranthis Bidentatae Radix-Paeoniae Radix Alba on Neuroinflammation and RhoA/ROCK2 Signaling Pathway in Parkinson's Disease Mouse Model / 中国实验方剂学杂志

ObjectiveTo investigate the protective effect and mechanism of Achyranthis Bidentatae Radix-Paeoniae Radix Alba on dopaminergic neurons in Parkinson's disease mouse model with the syndrome of ascendant hyperactivity of liver Yang. MethodThe C57BL/6 mice were randomly assigned into normal group， a model group， low-， medium， and high-dose （3.25， 6.5， 13 g·kg-1） Achyranthis Bidentatae Radix-Paeoniae Radix Alba groups， and a selegiline group （0.01 g·kg-1）. The mouse model of Parkinson's disease with the syndrome of ascendant hyperactivity of liver yang was established by intragastric administration of Fuzitang combined with intraperitoneal injection of 1-methyl-4-phenyl-1，2，3，6-tetrahydropyridine （MPTP）. The behavioral changes were evaluated by rotarod test and pole test. The protein levels of Ras homolog gene family member A （RhoA）， Rho-associated coiled-coil containing protein kinase 2 （ROCK2）， myosin light chain 1 （MLC1）， and α-synuclein in the substantia nigra were determined by Western blot. Real-time fluorescence quantitative PCR （Real-time PCR） was employed to determine the mRNA levels of RhoA， ROCK2， and MLC1 in the substantia nigra. Enzyme-linked immunosorbent assay （ELISA） was used to measure the levels of tumor necrosis factor-α （TNF-α） and interleukin-1β （IL-1β）. The ultrastructural changes of mouse neurons were observed under a transmission electron microscope. ResultCompared with the normal group， the modeling shortened the latency to fall， increased the average total time in the pole test （P<0.01）， and up-regulated the levels of RhoA， ROCK2， MLC1， TNF-α， α-synuclein， and IL-1β in the substantia nigra （P<0.05）. Compared with the model group， different doses of Achyranthis Bidentatae Radix-Paeoniae Radix Alba and selegiline prolonged the latency to fall， shortened the average total time in the pole test （P<0.05， P<0.01）， and down-regulated the levels of ROCK2， MLC1， α-synuclein， TNF-α， and IL-1β in a dose-dependent manner （P<0.05）. Further， the modeling decreased the number of cytoplasmic organelles and caused mitochondrial swelling and abnormal shape of endoplasmic reticulum compared with the normal group. The neurons in high-dose Achyranthis Bidentatae Radix-Paeoniae Radix Alba and selegiline groups showed intact nuclei， clear cell boundary， and normal endoplasmic reticulum shape. ConclusionThe combination of Achyranthis Bidentatae Radix and Paeoniae Radix Alba may improve the motor coordination ability of Parkinson's disease mouse model with the syndrome of ascendant hyperactivity of liver yang by inhibiting the neuroinflammation mediated by the RhoA/ROCK2 signaling pathway in the brain.

Relationship Between the Anxious Symptoms and the Neurotransmitter in Parkinson's Mice with Different Dosages of MPTP

ABSTRACT This study aims to explore the relationship between the anxious symptoms and the impairment of 5-hydroxytryptamine system in PD mice induced by different dosages of MPTP. The mice from the three model groups, the low-dose, dose and high-dose group, took longer time in the dark box than those in the control group (P<0.05). However, no statistically significant differences were found among the model groups. The number of open arm entry (OE) and the open arm time (OT) were significant lower in the model group than those in the control group in the elevated plus-maze test (P＜0.05). The percentage of OE in modle group was significantly lower compared with the control group (P＜0.05). The concentrations of striatum DA, HVA, 5-HT, and 5-HIAA were significantly reduced in the three model groups compared to the control group (P＜0.05). The 5-HT concentrations of high-dose group was significantly lower than those of the control group in the prefrontal cortex (P＜0.05). Anxiety symptoms were appeared in the three model groups of early PD mice, but no difference existed among these groups. The 5-hydroxytryptamine system was damaged after MPTP injection, which could lead to anxiety. However, the impairment of 5-hydroxytryptamine system induced by MPTP was dose-independent.

Exploration of establishing a tree shrew model of chronic gastrointestinal mucosal injury / 中国比较医学杂志

Objective To explore the feasibility of establishing a tree shrew model of chronic gastrointestinal mucosal injury. Methods A total of 12 adult male tree shrews were randomly divided into 3 groups. The experimental groups 1 and 2 were administered with intraperitoneal injection of 2 mg/(kg·d)and 1 mg/(kg·d)of 1-methyl-4-phenyl-1,2, 3,6-tetrahydropyridine(MPTP)once every day for 56 days, respectively. The control group was given the same volume of sterile saline at the corresponding time points. Changes in the body weight of the tree shrews were observed. The contents of dopamine in the cerebrospinal fluid were detected. Gastrointestinal morphology was observed by stereoscope and histopathological changes of the gastrointestinal mucosa were examined by HE staining. Results The body weight and the contents of dopamine in the cerebrospinal fluid of the tree shrews in the model group were significantly decreased(P< 0.05 for both). Pathological changes to some extent of the gastric antrum, the gastric body and the duodenum were observed, without obvious differences between the 2 mg/kg group and the 1 mg/kg group. No obvious changes were found in the control group. Conclusions Long-term intraperitoneal injection with a low dose of MPTP is a feasible method for the establishment of a tree shrew model of chronic gastrointestinal mucosal injury. The optimal dose is 2 mg/(kg·d)every day for 56 days.

Proposed Motor Scoring System in a Porcine Model of Parkinson's Disease induced by Chronic Subcutaneous Injection of MPTP

Destruction of dopaminergic neurons in the substantia nigra pars compacta (SNpc) is a common pathophysiology of Parkinson's disease (PD). Characteristics of PD patients include bradykinesia, muscle rigidity, tremor at rest and disturbances in balance. For about four decades, PD animal models have been produced by toxin-induced or gene-modified techniques. However, in mice, none of the gene-modified models showed all 4 major criteria of PD. Moreover, distinguishing between PD model pigs and normal pigs has not been well established. Therefore, we planned to produce a pig model for PD by chronic subcutaneous administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), neurotoxin. Changes in behavioral patterns of pigs were thoroughly evaluated and a new motor scoring system was established for this porcine model that was based on the Unified Parkinson's Disease Rating Scale (UPDRS) in human PD patients. In summary, this motor scoring system could be helpful to analyze the porcine PD model and to confirm the pathology prior to further examinations, such as positron emission tomography-computed tomography (PET-CT), which is expensive, and invasive immunohistochemistry (IHC) of the brain.

A comparison of spatial reference memory and dopamine level in the brain between different mouse models of Parkinson's disease / 中华行为医学与脑科学杂志

Objective To compare the difference of spatial reference memory and dopamine (DA) level in the brain between acute,subacute and chronic mouse model of Parkinson' s disease(PD) induced by 1-methyl-4-phenyl-1 ,2,3,6-tetrahydropyridine(MPTP) injection. Methods The acute,subacute and chronic mouse model of Parkinson' s disease were induced by injecting the same MPTP volume dose with different schedules. The spatial reference memory of mice was tested by morris water maze. Dopamine concentration in striatum, hippocampus and the prefrontal cortex were detected with HPLC. The number of tyrosine hydroxylase(TH)-positive cells in the substantia nigra of mice was detected by immunohistochemistry. Results The mean escape latency of the chronic but not the acute or subacute mouse model of Parkinson' s disease was significant longer ( P ＜ 0.05 ) than its control group. The striatum DA concentration of three test groups ( ( 1180. 1 ± 293.0 ) ng/ml, ( 1177.4 ± 450.5 ) ng/ml,( 1149.6 ± 353.0 ) ng/ml ) reduced significantly compared to their control groups ( ( 225.6 ± 79.7 ) ng/ml, ( 273.6± 64.9 ) ng/ml, ( 327. 1 ± 126.2 ) ng/ml, P ＜ 0.01 ). The prefrontal cortex DA concentration of the acute mouse model of Parkinson' s disease ( ( 65.3 ± 23.9 ) ng/ml ) was significant lower than its control group ( ( 41.2 ±18.8 )ng/ml, P ＜ 0.05 ). No significant changes of hippocampus DA concentration were seen between these test groups and their control groups. The number of TH positive cells in substantia nigra significantly decreased in three test groups compared to their control groups( P ＜ 0.05 ). Conclusion The difference of spatial reference memory between three regimens of the mouse model of Parkinson' s disease may not due to the difference of DA level in their brain.

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.

Neuroprotective effects of honokiol on mouse model with Parkinson's disease / 解放军医学杂志

Objective To explore the neuroprotective effect of honokiol against Parkinson's disease(PD)in mouse model,and investigate the possible mechanism involved.Methods 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)was injected into abdominal cavity of mouse to establish the PD model.Sixty C57BL/6 male mice were randomly allocated into five groups:control group,MPTP model group,amantadine group(positive control,40mg/kg),honokiol group A(10mg/kg)and honokiol group B(30mg/kg).Spontaneous movement test was used to measure the activity frequency of each mouse in 5 minutes.The technique of high performance liquid chromatography-electrochemistry was utilized to detect the changes of dopamine(DA)contents in mouse striatum.Results a)Since the involuntary movement appeared,such as trunk trembling,piloerection,tail extending and movement reduction,the PD model was regarded as having been reproduced successfully.b)The spontaneous movement frequency in 5 minutes of the mice in MPTP model group(102?7)was lower than that in the control group(583?11,P