MPTP-induced Injury Research Articles

Neuroprotective effect of cinnamaldehyde in MPTP-induced mouse model of subacute Parkinson's disease

This paper aims to explore the neuroprotective effect of cinnamaldehyde(CA) in mice with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced subacute Parkinson's disease(PD) and the mechanism. To be specific, male C57 BL/6 mice(n=72, SPF) were randomized into control group, model group, positive control(madopar 0.1 mg·g~(-1)) group, and low-dose, me-dium-dose, and high-dose CA groups(0.15, 0.30, 0.60 mg·g~(-1)). MPTP(intraperitoneal injection, 0.03 mg·g~(-1), once a day for 5 days) was used to induce subacute PD in mice except for the control group. The administration began from the day of modeling and lasted 19 days. On the 0 th, 12 th, and 19 th day, the open field test, pole test, and rotarod test were carried out. After the tests, the mice were killed and brains were separated. In addition, the organ index was measured. The number of cells in substantia nigra(SN) in the midbrain of MPTP-induced PD model mice was detected based on hematoxylin and eosin(HE) staining. The levels of tyrosine hydroxylase(TH)-and α-synuclein(α-Syn)-positive cells in SN were determined by immunohistochemical staining, and the protein levels of TH and α-Syn in SN by Western blot. The results showed that the MPTP-stimulated mice had abnormal behaviors such as erect hair, arched back, rigidity of the tail, slow movement, and tremor, decreased number of crossings and rearing, increased frequency of urination and defecation, longer time of pole climbing, and shorter time of staying on the rotating rod. In addition, the mice showed obvious damage of neurons in the SN and reduced neuron cells in irregular arrangement with some shrinking. In addition, the average optical density of TH in SN decreased and that of α-Syn increased. All these suggested the successful modeling. CA displayed obvious therapeutic effect on the PD mice, as manifested by the increased number of crossings and rearing, decreased frequency of urination and defecation, shorter time of climbing pole, longer time of staying on the rotating rod, and more neuron cells in the SN with a few pykno-tic cells. Moreover, CA significantly alleviated the decrease of TH and the overexpression of α-Syn in SN. As a result, the MPTP-induced injury of dopaminergic neurons was alleviated. The performance of 0.3 mg·g~(-1) CA was the best. This study is expected to lay a scientific basis for the development of CA products.

Yb3+, Er3+ Codoped Cerium Oxide Upconversion Nanoparticles Enhanced the Enzymelike Catalytic Activity and Antioxidative Activity for Parkinson's Disease Treatment.

Oxidative stress plays an important role in Parkinson's disease (PD) and is considered a therapeutic target for PD. However, most therapeutic antioxidants show limitations due to their low reactive oxygen species (ROS) catalytic properties and low crossing of blood-brain barrier. Herein, the antioxidative activity of Yb3+ and Er3+ double-doped CeO2-x (Yb/Er/CeO2-x) upconversion nanoparticles (UCNPs) is obtained for PD treatment. Doping of Yb3+ and Er3+ ions increases oxygen vacancies, which leads to higher enzymelike catalytic activities compared to CeO2-x nanoparticles alone. Tyrosine hydroxylase protein and glial fibrillary acidic protein expression in substantia nigra and striatum as well as the open-field activity test indicates that Yb/Er/CeO2-x is effective for treatment of PD. The activities of glutathione peroxidase and total antioxidant capacity increase and the production of ROS decreases with Yb/Er/CeO2-x UCNP treatment compared with MPTP-induced injury. This indicates that the mechanism of PD treatment is to catalyze ROS products. There have been no reports to date on the usage of Yb/Er/CeO2-x as an antioxidant for PD treatment. Yb/Er/CeO2-x UCNPs cross the blood-brain barrier and exhibit biocompatibility and antioxidant catalytic properties, which decrease the ROS and effectively help in treating PD.

CHIP protects against MPP+/MPTP-induced damage by regulating Drp1 in two models of Parkinson's disease.

Mitochondrial dysfunction has been implicated in the pathogenesis of Parkinson’s disease (PD). Carboxyl terminus of Hsp70-interacting protein (CHIP) is a key regulator of mitochondrial dynamics, and mutations in CHIP or deficits in its expression have been associated with various neurological diseases. This study explores the protective role of CHIP in cells and murine PD models. In SH-SY5Y cell line, overexpression of CHIP improved the cell viability and increased the ATP levels upon treatment with 1-methyl-4-phenylpyridinium (MPP+). To achieve CHIP overexpression in animal models, we intravenously injected mice with AAV/BBB, a new serotype of adeno-associated virus that features an enhanced capacity to cross the blood-brain barrier. We also generated gene knock-in mice that overexpressed CHIP in neural tissue. Our results demonstrated that CHIP overexpression in mice suppressed 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced damage, including movement impairments, motor coordination, and spontaneous locomotor activity, as well as loss of dopaminergic neurons. In vitro and in vivo experiments showed that overexpression of CHIP inhibited the pathological increase in Drp1 observed in the PD models, suggesting that CHIP regulates Drp1 degradation to attenuate MPP+/MPTP-induced injury. We conclude that CHIP plays a protective role in MPP+/MPTP-induced PD models. Our experiments further revealed that CHIP maintains the integrity of mitochondria.

Role of trehalose in MPTP-induced injury of SH-SY5Y cells and its mechanism

Objective: To establish a Parkinson's disease (PD) cell model of human neuroblastoma cells (SH-SY5Y) induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and to explore the possible mechanism of trehalose in PD. Methods: SH-SY5Y cells were cultured and divided into four groups: control group, trehalose group, MPTP group and trehalose +MPTP group.The trehalose was detected with MTT assay for its effect of on the viability of injured SH-SY5Y cells. The lactate dehydrogenase (LDH) was detected by kit for its level in culture medium. The ROS was assessed by DCFH-DA for its average level in cells. Besides, Hoechst 33342 staining was used to detect apoptosis. The endoplasmic reticulum stress (ERS) related proteins GRP78, IRE1, PERK and ATF6 were also detected by Western blot for its expression levels. Results: The survival rate of MPTP group decreased significantly and the levels of LDH and ROS increased compared with the control group. In addition, the survival rate of cells in trehalose +MPTP group increased significantly and the levels of LDH and ROS decreased compared with MPTP group. The expressions of GRP78, IRE1, p- IRE1, PERK, p- PERK and ATF6 in MPTP group increased, but decreased in trehalose +MPTP group compared with the control group. Conclusion: Trehalose has a significant protective effect on MPTP-induced SH-SY5Y cells injury, and its mechanism may be related to the effect of trehalose on oxidative stress by inhibiting ER stress response.

Design and evaluation of mucoadhesive microemulsion for neuroprotective effect of ibuprofen following intranasal route in the MPTP mice model

Background: The present study is to investigate the neuroprotective effect of ibuprofen by intranasal administration of mucoadhesive microemulsion (MMEI) against inflammation-mediated by dopaminergic neurodegeneration in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of Parkinson’s disease (PD).Methods: Ibuprofen-loaded polycarbophil-based MMEI was developed by using response surface methodology (RSM). Ibuprofen with dose of 2.86 mg/kg/day was administered intranasally to male C57BL/6 mice for two consecutive weeks which were pre-treated with four intraperitoneal injections of MPTP (20 mg/kg of body weight) at 2 h intervals. Immunohistochemistry was performed.Results: Optimal MMEI was stable and non-ciliotoxic with 66.29 ± 4.15 nm as average globule size and −20.9 ± 3.98 mV as zeta potential. PDI value and transmission electron microscopy result showed the narrow globule size distribution of MMEI. The result showed that all three independent variables had a significant effect (p < 0.05) on the responses. Rota-rod and open-field test findings revealed the significant improvement in motor performance and gross behavioral activity of the mice. The results from in vivo study and immunohistochemistry showed that nasal administration of Ibuprofen significantly reduced the MPTP-mediated dopamine depletion. Furthermore TH neurons count in the substantia nigra and the density of striatal dopaminergic nerve terminals were found to be significant higher for ibuprofen treated groups.Conclusion: Findings of the investigation revealed that Ibuprofen through developed MMEI was shown to protect neurons against MPTP-induced injury in the Substantia nigra pars compacta (SNpc) and striatum and hence, could be a promising approach for brain targeting of Ibuprofen through intranasal route to treat PD.

Neuroprotective effect of ibuprofen by intranasal application of mucoadhesive nanoemulsion in MPTP induced Parkinson model

This study was to investigate the neuroprotective effect of Ibuprofen by intranasal route against inflammation-mediated by dopaminergic neurodegeneration in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mice model of Parkinson’s disease (PD). Ibuprofen loaded sodium hyaluronate based mucoadhesive nanoemulsion (MNEI) was developed by using response surface methodology (RSM) and was characterized. Male C57BL/6 mice were first treated with four intraperitoneal injections of MPTP (20 mg/kg of body weight) at 2 h intervals followed by Ibuprofen for 2 consecutive weeks at 2.86 mg/kg of body weight per day. Optimal MNEI containing 3 % Labrafil M 1944 CS as oil phase, 36 % of Accenon CC and Transcutol P at 3:1 ratio and 0.5 % sodium hyaluronate was stable, non-ciliotoxic with 46.3 ± 2.28 nm as average globule size PdI value and TEM result showed the narrow size distribution of MNEI. The result showed that all three independent variables had a significant effect (p < 0.05) on the responses. In-vivo results revealed significant reduction of MPTP-mediated dopamine depletion after nasal administration of Ibuprofen through MNEI. MPTP intoxication significantly decreased striatal DA content to 29.92 % which was elevated to 58.21 % after Ibuprofen treatment using MNEI. Significant improvement in motor performance and gross behavioural activity of the mice was observed through the findings of rota-rod and open field test findings. Findings of the investigation revealed that Ibuprofen through developed MNEI was shown to protect neurons against MPTP-induced injury in the striatum and could be a promising approach to treat PD.

MPTP로 유도된 Parkinson's disease 동물 모델에서 열다한소탕 가감방 (MYH)의 신경 세포 보호 효과

Objectives To evaluate the neuroprotective effects of modified Yuldahanso-tang (MYH) in a Parkinson's disease mouse model. Methods 1) Four groups (each of 8 rats per group) were used in this study. 2) The neuroprotective effect of MYH was examined in a Parkinson's disease mouse model. C57BL/6 mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg/day), intraperitoneal (i.p.) for 5 days. 3) The brains of 2 mice per group were removed and frozen at <TEX>$-20^{\circ}C$</TEX>, and the striatum-substantia nigra part was seperated. The protein volume was measured by Bradford method following Bio-Rad protein analyzing kit. Using mouse/Rat Dopamine ELISA Assay Kit. 4) The brains of 2 mice per group were separated and removed. TH-immunohistochemical was examined in the MPTP-induced Parkinson's disease mice to evaluate the neuroprotective effects of MYH on ST and SNpc. 5) Two mice out of each group were anesthetized and skulls were opened from occipital to frontal direction to take out the brains. The brains added TTC solution for 20 minutes for staining. 6) The water tank used for morris water maze test was filled with <TEX>$28^{\circ}C$</TEX> water, and a round platform of 10cm in diameter was installed for mice to step on. The study was carried out once a day within 30 seconds, keep exercising to step on the platform in the pool. 7) The brains of two mice out of each group were fixed in 10% formaldehyde solution and paraphillin substance was infiltrated. They were fragmented by microtome, and observed under an optical microscope after Hematoxylin & Eosin staining. 8) A round acrylic cylinder with its upper side open was filled with clean water and depressive mouse models were forced to swim for 15 minutes. After 24 hours the animals were put in the same equipment for 5 minutes and were forced to swim. 9) The convenient, simple, and accurate high-performance liquid chromatography (HPLC) method was established for simultaneous determination of Neurotransmitters in MPTP-MYH group. Results 1) MYH possess Dopamine cell protective effect on MPTP-induced injury in striatum and substantia nigra pars compacta. 2) MYH inhibits the loss of tyrosine hydroxylase-immunoreacitive (TH-IR) cells in the striatum and substantia nigra pars compacta on MPTP-induced injury in C57BL/6 mice. 3) MYH possesses improvement effect on MPTP-induced memory deterioration in C57BL/6 mice through the reduction of prolongated Sort of lost time by MPTP injection using the Morris water maze test. 4) MYH possesses hippocampal neuron protective effect on MPTP-induced injury in C57BL/6 mice. 5) MYH possesses improvement effect on MPTP-induced motor behaviour deficits and depression in C57BL/6 mice through the reduction of prolongated losing motion by MPTP injection using the Forced swimming test. 6) MYH increases serotonin product amount on MPTP-induced injury in C57BL/6 mice. Conclusions This experiment suggests that the neuroprotective effect of MYH is mediated by the increase in Dopamin, TH-ir cell, Hippocampus and Serotonin. Furthermore, MYH essential oil may serve as a potential preventive or therapeutic agent regarding Parkinson's disease.

Small peptide inhibitor of JNK3 protects dopaminergic neurons from MPTP induced injury via inhibiting the ASK1-JNK3 signaling pathway.

Introduction and AimsThe ASK1-JNK3 signaling pathway plays a pivotal role in the pathogenesis of Parkinson's disease (PD). The specific binding of β-arrestin2 to JNK3 is essential for activation of the ASK1-JNK3 cascade, representing a potential therapeutic target for preventing dopaminergic neuronal death in PD. The aim of this study was to identify a novel strategy for the prevention of dopaminergic neuronal death in PD.MethodsBased on the specific binding of β-arrestin2 to JNK3, a 21-amino-acid fusion peptide, termed JNK3-N-Tat, was synthesized. We evaluated the ability of this peptide to inhibit the binding of β-arrestin2 to its target domain in JNK3 in vitro and in vivo.ResultsThe JNK3-N-Tat peptide inhibited activation of the ASK1-JNK3 cascade by disrupting the interaction between β-arrestin2 and JNK3. JNK3-N-Tat exerted beneficial effects through pathways downstream of JNK3 and improved mitochondrial function, resulting in attenuated MPP+/MPTP-induced damage. JNK3-N-Tat protected mesencephalic dopaminergic neurons against MPTP-induced toxicity.ConclusionsJNK3-N-Tat, a JNK3-inhibitory peptide, protects dopaminergic neurons against MPP+/MPTP-induced injury by inhibiting the ASK1-JNK3 signaling pathway.

Autologous transplantation of GDNF-expressing mesenchymal stem cells protects against MPTP-induced damage in cynomolgus monkeys

Glial cell-derived neurotrophic factor (GDNF) has shown beneficial effects in models of Parkinson's disease. The mild results observed in the double-blind clinical trial by intraputamenal infusion of recombinant GDNF proteins warrant a search for alternative delivery methods. In this study, we investigated the function of autologous mesenchymal stem cells (MSCs) expressing GDNF (GDNF-MSCs) for protection against MPTP-induced injury in cynomolgus monkeys. MSCs were obtained from the bone marrow of individual monkeys and gene-modified to express GDNF. Following unilateral engraftment of GDNF-MSCs into the striatum and substantia nigra, the animals were challenged with MPTP to induce a stable systemic Parkinsonian state. The motor functions were spared in the contralateral limbs of monkeys receiving GDNF-MSCs, but not in those receiving MSCs alone. In the striatum of the grafted hemisphere, dopamine levels were higher and dopamine uptake was enhanced. The results suggest that autologous MSCs may be a safe vehicle to deliver GDNF for enhancing nigro-striatum functions.

Potential neuroprotective effect of ibuprofen, insights from the mice model of Parkinson's disease

BackgroundParkinson's disease (PD) is one of the most common neurodegenerative diseases. An inflammatory reaction seems to be involved in the pathological process in PD. Prospective clinical studies with various nonsteroidal anti-inflammatory drugs (NSAIDs) have shown that ibuprofen decreases the risk of PD. In the present study we investigated the influence of ibuprofen on dopaminergic neuron injury in the mice model of PD. MethodsTwelve-month-old male C57Bl mice were injected with MPTP together with various doses of ibuprofen (10, 30 or 50mg/kg), administered 1h before MPTP injection for 7 consecutive days. Evaluation concerned dopamine content in the striatum, tyrosine hydroxylase (TH) protein and α-synuclein expression measured 7 and 21 days post MPTP administration (dpa). ResultsMPTP caused injury to dopaminergic neuron endings in the striatum: dopamine content decreased by about 90% 7dpa and by 85% 21dpa; TH protein expression diminished by 21% 7dpa; α-synuclein level decreased by 10 and 26% 7 and 21dpa, respectively. Ibuprofen administration to mice treated with MPTP significantly increased the level of dopamine in the striatum 7 and 21dpa. It also prevented TH protein decrease and increased α-synuclein level 21dpa. ConclusionsIbuprofen was shown to protect neurons against MPTP-induced injury in the striatum. The possible mechanism of the neuroprotective effect of ibuprofen might be associated with decreased dopamine turnover and cyclooxygenases inhibition resulting in lower reactive oxygen species formation.

Recovery of hypothalamic tuberoinfundibular dopamine neurons from acute toxicant exposure is dependent upon protein synthesis and associated with an increase in parkin and ubiquitin carboxy-terminal hydrolase-L1 expression

Hypothalamic tuberoinfundibular dopamine (TIDA) neurons remain unaffected in Parkinson disease (PD) while there is significant degeneration of midbrain nigrostriatal dopamine (NSDA) neurons. A similar pattern of susceptibility is observed in acute and chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse and rotenone rat models of degeneration. It is not known if the resistance of TIDA neurons is a constitutive or induced cell-autonomous phenotype for this unique subset of DA neurons. In the present study, treatment with a single injection of MPTP (20mg/kg; s.c.) was employed to examine the response of TIDA versus NSDA neurons to acute injury. An acute single dose of MPTP caused an initial loss of DA from axon terminals of both TIDA and NSDA neurons, with recovery occurring solely in TIDA neurons by 16h post-treatment. Initial loss of DA from axon terminals was dependent on a functional dopamine transporter (DAT) in NSDA neurons but DAT-independent in TIDA neurons. The active metabolite of MPTP, 1-methyl, 4-phenylpyradinium (MPP+), reached higher concentration and was eliminated slower in TIDA compared to NSDA neurons, which indicates that impaired toxicant bioactivation or distribution is an unlikely explanation for the observed resistance of TIDA neurons to MPTP exposure. Inhibition of protein synthesis prevented TIDA neuron recovery, suggesting that the ability to recover from injury was dependent on an induced, rather than a constitutive cellular mechanism. Further, there were no changes in total tyrosine hydroxylase (TH) expression following MPTP, indicating that up-regulation of the rate-limiting enzyme in DA synthesis does not account for TIDA neuronal recovery. Differential candidate gene expression analysis revealed a time-dependent increase in parkin and ubiquitin carboxyl-terminal hydrolase-L1 (UCH-L1) expression (mRNA and protein) in TIDA neurons during recovery from injury. Parkin expression was also found to increase with incremental doses of MPTP. The increase in parkin expression occurred specifically within TIDA neurons, suggesting that these neurons have an intrinsic ability to up-regulate parkin in response to MPTP-induced injury. These data suggest that TIDA neurons have a compensatory mechanism to deal with toxicant exposure and increased oxidative stress, and this unique TIDA neuron phenotype provides a platform for dissecting the mechanisms involved in the natural resistance of central DA neurons following toxic insult.

Protection but maintained dysfunction of nigral dopaminergic nerve cell bodies and striatal dopaminergic terminals in MPTP-lesioned mice after acute treatment with the mGluR5 antagonist MPEP

The mGluR5 antagonist MPEP was used to study the role of mGluR5 in MPTP-induced injury of the nigrostriatal DA neurons. The findings indicate that acute blockade of mGluR5 may result in neuroprotective actions against MPTP neurotoxicity on nigral DA cell bodies and striatal DA terminals using stereological analysis of TH immunoreactivity and microdensitometry. Biochemical analysis showed no restoration of DA levels and metabolism indicating a maintained reduction of DA transmission.

Group I mGluR antagonist AIDA protects nigral DA cells from MPTP-induced injury.

The effects of i.c.v. injection of AIDA, a group I mGluR antagonist, were studied on the nigral DA cells after MPTP-induced injury in the black mouse, using TH immunocytochemistry and unbiased stereology. MPTP reduced the total number of TH-IR neurons by 55.2% and non-TH-IR neurons by 27.5%. A 15 min AIDA pre-treatment (10 nmol) selectively counteracted the loss of TH-IR cells caused by MPTP as evaluated 10 days after the insult without changing the total number of non-neuronal cell nuclei. The results suggest that group I mGluR antagonists may have a neuroprotective role against MPTP-induced degeneration of DA neurons and thus probably also against neurodegenerative processes occurring in Parkinson's disease.

Alpha-synuclein up-regulation in substantia nigra dopaminergic neurons following administration of the parkinsonian toxin MPTP.

Mutations in alpha-synuclein cause a form of familial Parkinson's disease (PD), and wild-type alpha-synuclein is a major component of the intraneuronal inclusions called Lewy bodies, a pathological hallmark of PD. These observations suggest a pathogenic role for alpha-synuclein in PD. Thus far, however, little is known about the importance of alpha-synuclein in the nigral dopaminergic pathway in either normal or pathological situations. Herein, we studied this question by assessing the expression of synuclein-1, the rodent homologue of human alpha-synuclein, in both normal and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated mice. In normal mice, detectable levels of synuclein mRNA and protein were seen in all brain regions studied and especially in ventral midbrain. In the latter, there was a dense synuclein-positive nerve fiber network, which predominated over the substantia nigra, and only few scattered synuclein-positive neurons. After a regimen of MPTP that kills dopaminergic neurons by apoptosis, synuclein mRNA and protein levels were increased significantly in midbrain extracts; the time course of these changes paralleled that of MPTP-induced dopaminergic neurodegeneration. In these MPTP-injected mice, there was also a dramatic increase in the number of synuclein-immunoreactive neurons exclusively in the substantia nigra pars compacta; all synuclein-positive neurons were tyrosine hydroxylase-positive, but none coexpressed apoptotic features. These data indicate that synuclein is highly expressed in the nigrostriatal pathway of normal mice and that it is up-regulated following MPTP-induced injury. In light of the synuclein alterations, it can be suggested that, by targeting this protein, one may modulate MPTP neurotoxicity and, consequently, open new therapeutic avenues for PD.