Neuroprotective and neurorescue effect of black tea extract in 6-hydroxydopamine-lesioned rat model of Parkinson's disease

In the present study, an attempt has been made to explore the neuroprotective and neuroreparative (neurorescue) effect of black tea extract (BTE) in 6-hydroxydopamine (6-OHDA)-lesioned rat model of Parkinson's disease (PD). In the neuroprotective (BTE + 6-OHDA) and neurorescue (6-OHDA + BTE) experiments, the rats were given 1.5% BTE orally prior to and after intrastriatal 6-OHDA lesion respectively. A significant recovery in d-amphetamine induced circling behavior (stereotypy), spontaneous locomotor activity, dopamine (DA)-D2 receptor binding, striatal DA and 3-4 dihydroxy phenyl acetic acid (DOPAC) level, nigral glutathione level, lipid peroxidation, striatal superoxide dismutase and catalase activity, antiapoptotic and proapoptotic protein level was evident in BTE + 6-OHDA and 6-OHDA + BTE groups, as compared to lesioned animals. BTE treatment, either before or after 6-OHDA administration protected the dopaminergic neurons, as evident by significantly higher number of surviving tyrosine hydroxylase immunoreactive (TH-ir) neurons, increased TH protein level and TH mRNA expression in substantia nigra. However, the degree of improvement in motor and neurochemical deficits was more prominent in rats receiving BTE before 6-OHDA. Results suggest that BTE exerts both neuroprotective and neurorescue effects against 6-OHDA-induced degeneration of the nigrostriatal dopaminergic system, suggesting that possibly daily intake of BTE may slow down the PD progression as well as delay the onset of neurodegenerative processes in PD.     

miR-15b对MPP+损伤SH-SY5Y细胞中α突触核蛋白表达的影响

目的研究miR-15b对MPP+(1-甲基-4-苯基-吡啶离子)损伤SH-SY5Y细胞中α突触核蛋白表达的影响以及在帕金森病(Parkinson disease,PD)发病机制中的作用。方法通过CCK-8检测出MPP+诱导SH-SY5Y细胞为PD细胞模型的最适浓度和时间,然后将过表达和沉默miR-15b的质粒转染到PD细胞模型内,再通过Real Time-PCR和Western Blot检测miR-15b和α突触核蛋白的表达量。结果 SH-SY5Y细胞经MPP+诱导后细胞形态发生改变、细胞增殖能力降低,过表达miR-15b后α-synuclein和α突触核蛋白的表达量均降低(P 0. 05),沉默miR-15b后α-synuclein和α突触核蛋白的表达量均升高(P 0. 05)。结论 miR-15b可以抑制PD细胞模型内α-synuclein和α突触核蛋白的表达。miR-15b可能参与了帕金森病患者中脑黑质多巴胺能神经元内α突触核蛋白的富集调节机制。     

NAIP protects the nigrostriatal dopamine pathway in an intrastriatal 6-OHDA rat model of Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder of the basal ganglia, associated with the inappropriate death of dopaminergic neurons of the substantia nigra pars compacta (SNc). Here, we show that adenovirally mediated expression of neuronal apoptosis inhibitor protein (NAIP) ameliorates the loss of nigrostriatal function following intrastriatal 6-OHDA administration by attenuating the death of dopamine neurons and dopaminergic fibres in the striatum. In addition, we also addressed the role of the cysteine protease caspase-3 activity in this adult 6-OHDA model, because a role for caspases has been implicated in the loss of dopamine neurons in PD, and because NAIP is also a reputed inhibitor of caspase-3. Although caspase-3-like proteolysis was induced in the SNc dopamine neurons of juvenile rats lesioned with 6-OHDA and in adult rats following axotomy of the medial forebrain bundle, caspase-3 is not induced in the dopamine neurons of adult 6-OHDA-lesioned animals. Taken together, these results suggest that therapeutic strategies based on NAIP may have potential value for the treatment of PD.     

Genetics of Parkinson's disease

The etiology of most cases of Parkinson's disease (PD) remains unknown. In recent years, however, research has successfully focused on genetic factors contributing to the degeneration of dopaminergic neurons. Causative mutations have been identified in several monogenically inherited forms of the disease. Although these genetic forms of PD are usually rare, the gene discoveries are likely to identify molecular pathways that are also relevant in the sporadic disorder. These studies have led to the identification of (i) the central role of α-synuclein aggregation, secondary to either point mutations or an amplification of the α-synuclein gene; and (ii) the relevance of defects in the proteasomal protein degradation pathway in the molecular pathogenesis of recessive parkin-linked forms of PD. The recent discoveries of two additional recessive forms associated with mutations in the genes DJ-1 and PINK1 have brought the mitochondrial energy metabolism and the cell's defence against toxic free radicals into the focus of research.     

Knocking Out DJ-1 Attenuates Astrocytes Neuroprotection Against 6-Hydroxydopamine Toxicity

Astrocytes are the most abundant glial cell type in the brain. Impairment in astrocyte functions can critically influence neuronal survival and leads to neurodegeneration. Parkinson’s disease (PD) is a common neurodegenerative disorder, characterized by motor dysfunction that results from progressive neuronal loss. Astrocytic dysfunction was demonstrated in human samples and in experimental models of PD. Mutations in DJ-1 (PARK7) leading to loss of functional protein cause familial PD and enhance sensitivity to oxidative insults. Recently, an increase in DJ-1’s expression was found in reactive astrocytes in various neurodegenerative disorders. Here we show that lack of DJ-1 attenuates astrocytes’ ability to support neuronal cells, thereby leading to accelerated neuronal damage. DJ-1 knockout mice demonstrated increased vulnerability in vivo to 6-hydroxydopamine (6-OHDA) hemiparkinsonian PD model. Astrocytes isolated from DJ-1 knockout mice showed an inferior ability to protect human neuroblastoma cells against 6-OHDA insult both by co-culture and through their conditioned media, as compared to wild-type astrocytes. DJ-1 knockout astrocytes showed blunted ability to increase the expression of cellular protective mechanisms against oxidative stress mediated via Nrf-2 and HO-1 in response to exposure to 6-OHDA. These experiments demonstrated that lack of DJ-1 impairs astrocyte-mediated neuroprotection.     

Glucagon-like peptide-1/glucose-dependent insulinotropic polypeptide dual receptor agonist DA-CH5 is superior to exendin-4 in protecting neurons in the 6-hydroxydopamine rat Parkinson model

Patients with Parkinson’s disease (PD) have impaired insulin signaling in the brain. Incretin hormones, including glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), can re-sensitize insulin signaling. In a recent phase II clinical trial, the first GLP-1 mimic, exendin-4, has shown reliable curative effect in patients with PD. DA-CH5 is a novel GLP-1/GIP receptor unimolecular co-agonist with a novel peptide sequence added to cross the blood-brain barrier. Here we showed that both exendin-4 and DA-CH5 protected against 6-hydroxydopamine (6-OHDA) cytotoxicity, inhibited apoptosis, improved mitogenesis and induced autophagy flux in SH-SY5Y cells via activation of the insulin receptor substrate-1 (IRS-1)/alpha serine/threonine-protein kinase (Akt)/cAMP response element-binding protein (CREB) pathway. We also found that DA-CH5 (10 nmol/kg) daily intraperitoneal administration for 30 days post-lesion alleviated motor dysfunction in rats and prevented stereotactic unilateral administration of 6-OHDA induced dopaminergic neurons loss in the substantia nigra pars compacta. However, DA-CH5 showed curative effects in reducing the levels of α-synuclein and the levels of pro-inflammatory cytokines (tumor necrosis factor-α, interleukin-1β). It was also more effective than exendin-4 in inhibiting apoptotic process and protecting mitochondrial functions. In addition, insulin resistance was largely alleviated and the expression of autophagy-related proteins was up-regulated in PD model rats after DA-CH5 treatment. These results in this study indicate DA-CH5 plays a therapeutic role in the 6-OHDA-unilaterally lesioned PD rat model and is superior to GLP-1 analogue exendin-4. The study was approved by the Animal Ethics Committee of Shanxi Medical University of China.

Chinese Library Classification No. R453; R741; Q421     

Use of viral vectors to create animal models for Parkinson's disease

Parkinson's disease is a neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra. While sporadic in the majority of cases, PD-linked dominant mutations in the α-synuclein and LRRK-2 genes, and recessive mutations in the parkin, DJ-1 and PINK-1 genes have been identified in PD families in recent years. In this review we describe viral animal models for PD, i.e. models that are based on PD-associated mutations, and have been generated by viral delivery of the respective disease genes to the substantia nigra of rodents and non-human primates. To date, viral PD models comprise α-synuclein and LRRK-2-based overexpression models, as well as models that mimic parkin loss of function by overexpression of the parkin substrates Pael-R, CDCrel-1, p38/JTV or synphilin-1. These viral models provide valuable insights into Parkinson disease mechanisms, help to identify therapeutic targets and may contribute to the development of therapeutic approaches.     

A brief overview of tyrosine hydroxylase and α-synuclein in the Parkinsonian brain

Parkinson's disease (PD) is associated with neurodegeneration of the nigrostriatal tract and is accompanied with loss of tyrosine hydroxylase (TH) and dopamine (DA). Development of neuroprotective strategies targeting PD is often undermined by lack of proper understanding of processes contributing to the pathology. In this mini review we have tried to briefly outline the involvement of TH and α-synuclein in PD. Aberrant expression of α-synuclein is toxic to dopaminergic neurons. It interacts with ubiquitin-proteasomal processing system, implicated in oxidative injury and mitochondrial dysfunction which ultimately induce neurodegenration and cell death. The contributions of DJ-1 in TH regulation have also been discussed. Brain specific TH expression with the combined use of the pegylated immunoliposome (PILs) gene transfer technology and brain specific promoters as a new approach to treat PD has also been included.     

一种帕金森病大鼠模型的建立及评价

目的探讨应用6-羟基多巴胺（6-OHDA）毁损大鼠黑质致密部制作偏侧帕金森病（PD）模型的方法和应用价值。方法采用立体定向微量注射6-OHDA于大鼠黑质致密部,观察经阿朴吗啡诱导后大鼠的行为及黑质多巴胺能神经元形态学变化。结果部分大鼠注射后即出现行动迟缓、少动、竖毛、躬身、尾部强直、肢体震颤、嗅探和易激惹等异常行为。术后4周时,共33只大鼠经阿朴吗啡诱导后在30min（P〈0．01）的平均旋转圈数〉7r／min,达到成功模型的标准,模型成功率为82．5％（33／40）。免疫组化观察发现模型组大鼠注射侧黑质区多巴胺能神经元较对侧和对照组注射侧区明显减少（P〈0．01）。结论利用6-OHDA毁损大鼠黑质致密部可以较快建立稳定的PD大鼠模型,方法简便实用,动物死亡率低,模型成功率高。     

Expression of glutamate receptors in the human and rat basal ganglia: Effect of the dopaminergic denervation on AMPA receptor gene expression in the striatopallidal complex in parkinson's disease and rat with 6-OHDA lesion

The overactivity of subthalamopallidal and corticostriatal glutamatergic neurons observed in Parkinson's disease (PD) suggests that antagonists of glutamate receptor could be used to alleviate the motor symptoms of the disease. In this study, we analysed two features of the striatopallidal complex: (1) the distribution of α-amino-3 hydroxy-5-methyl-4-isoxasol-propionate (AMPA) and kainate receptors and their corresponding mRNA by immunohistochemistry and in situ hybridisation and (2) the effect of dopaminergic denervation on AMPA receptor gene expression in PD patients and rats with 6-hydroxydopamine (6-OHDA)-induced degeneration of the nigrostriatal dopaminergic system. All AMPA receptor mRNAs and proteins (GluR1–4) were detected in the internal segment of the globus pallidus (GPi). Among kainate receptors, only KA1 and KA2 were detectable and only at a low level. Only GluR4 protein was detected in the neuropil of the GPi. In the striatum, GluR1, GluR2, and GluR3 were detected in about 70% of medium-sized and large neurons. By contrast, GluR4 mRNA was detected in only a small number of large and medium-sized neurons. Among kainate receptors, GluR6, GluR7, and KA2 were detected in about 50–60% of medium-sized neurons, whereas GluR5 and KA1 were restricted to 1–2% and 20–30% of these neurons, respectively. These results suggest that antagonists of AMPA and kainate receptors could be effective in alleviating motor symptoms in Parkinson's disease by blocking the overstimulation of pallidal and striatal neurons by glutamate. A significant decrease in GLuR1 gene expression (−33%) was observed in the neurons of the GPi in PD patients and in rat entopeduncular nucleus ipsilateral to the 6-OHDA lesion (−20%). GluR2, GluR3, and GluR4 mRNA levels in the GPi and GluR1–4 mRNA levels in the striatum were unchanged in PD patients and 6-OHDA-lesioned rats compared with their respective controls. These data suggest that dopamine positively regulates only GluR1 gene expression in the GPi. © 1996 Wiley-Liss, Inc.     

Neurotrophic effects of bone morphogenetic protein-7 in a rat model of Parkinson's disease

Previous studies have demonstrated that pretreatment with bone morphogenetic protein-7 (BMP7) reduces ischemic neuronal injury in vivo. Moreover, exogenous application of BMP7 increases both the number of tyrosine hydroxylase (+) cells and dopamine (DA) uptake in rat mesencephalic cell cultures. The purpose of this study was to investigate the in vivo effects of BMP7 on 6-hydroxydopamine (6-OHDA) induced lesioning of midbrain DA neurons. Adult Fischer 344 rats were anesthetized and injected with BMP7 or vehicle into the left substantia nigra, followed by local administration of 9 microg of 6-OHDA into the left medial forebrain bundle. The lesioned animals that received BMP7 pretreatment, as compared to vehicle/6-OHDA controls, had a significant reduction in methamphetamine-induced rotation 1 month after the surgery. BMP7-pretreatment partially preserved KCl-induced dopamine release in the lesioned striatum and significantly increased TH immunoreactivity in the lesioned nigra and striatum. In summary, our data suggest that BMP7 has neuroprotective and/or neuroreparative effects against 6-OHDA lesioning of the nigrostriatal DA pathway in an animal model of Parkinson's disease (PD).     

Spinal cord dopamine receptor expression and function in mice with 6-OHDA lesion of the A11 nucleus and dietary iron deprivation

It is suggested that dysfunction of the diencephalospinal dopaminergic (DAergic) pathway may cause restless legs syndrome. We examined the mRNA and protein levels as well as DA receptor subtypes function within the lumbar spinal cord of an RLS animal model. C57BL/6 male mice with or without iron deprivation were lesioned with 6-hydroxydopamine (6-OHDA) in the bilateral A11 nuclei. Locomotor behaviors were observed. DA concentration, mRNA, and protein levels of D1, D2, and D3 receptors in the lumbar spinal cords were analyzed, and the specific binding of D1, D2, and D3 receptors was determined using [(3)H]SCH23390, [(3)H]Spiperone, and [(3)H]PD128907 radioligands respectively. The behavioral tests showed that the locomotor activities were increased significantly in the mice treated with iron-deficiency (ID) diet and 6-OHDA lesions, which were reversed by the D2/D3 agonist ropinirole. DA in the spinal cord was decreased significantly by 6-OHDA lesioning in A11. D2/D3 mRNA and protein levels as well as their binding capacity in the spinal cord were decreased significantly by 6-OHDA lesions. ID with 6-OHDA lesions produced a synergistic greater decrease of D2 binding. Although ID increased D1 mRNA and protein expression in the spinal cord, it did not significantly change D1 receptor binding. The present study suggests that ID and 6-OHDA lesions in A11 nuclei differentially altered the D1, D2, and D3 receptors expression and binding capacity in the lumbar spinal cord of RLS animal model, which was accompanied by changes in locomotor activities.     

Differential effects of vagus nerve stimulation paradigms guide clinical development for Parkinson’s disease

BackgroundVagus nerve stimulation (VNS) modifies brain rhythms in the locus coeruleus (LC) via the solitary nucleus. Degeneration of the LC in Parkinson’s disease (PD) is an early catalyst of the spreading neurodegenerative process, suggesting that stimulating LC output with VNS has the potential to modify disease progression. We previously showed in a lesion PD model that VNS delivered twice daily reduced neuroinflammation and motor deficits, and attenuated tyrosine hydroxylase (TH)-positive cell loss.ObjectiveThe goal of this study was to characterize the differential effects of three clinically-relevant VNS paradigms in a PD lesion model.MethodsEleven days after DSP-4 (N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine, noradrenergic lesion, administered systemically)/6-OHDA (6-hydroxydopamine, dopaminergic lesion, administered intrastriatally) rats were implanted with VNS devices, and received either low-frequency VNS, standard-frequency VNS, or high-frequency microburst VNS. After 10 days of treatment and behavioral assessment, rats were euthanized, right prefrontal cortex (PFC) was dissected for norepinephrine assessment, and the left striatum, bilateral substantia nigra (SN), and LC were sectioned for immunohistochemical detection of catecholamine neurons, α-synuclein, astrocytes, and microglia.ResultsAt higher VNS frequencies, specifically microburst VNS, greater improvements occurred in motor function, attenuation of TH-positive cell loss in SN and LC, and norepinephrine concentration in the PFC. Additionally, higher VNS frequencies resulted in lower intrasomal α-synuclein accumulation and glial density in the SN.ConclusionsThese data indicate that higher stimulation frequencies provided the greatest attenuation of behavioral and pathological markers in this PD model, indicating therapeutic potential for these VNS paradigms.     

Comparison of the behavioural and histological characteristics of the 6-OHDA and α-synuclein rat models of Parkinson's disease

Development of relevant models of Parkinson's disease (PD) is essential for a better understanding of the pathological processes underlying the human disease and for the evaluation of promising targets for therapeutic intervention. To date, most pre-clinical studies have been performed in the well-established rodent and non-human primate models using injection of 6-hydroxydopamine (6-OHDA) or 1-methyl-4-phenyl-1,2,3,6-tetrahydroxypyridine (MPTP). Overexpression of the disease-causing protein α-synuclein (α-syn), using adeno-associated viral (AAV) vectors, has provided a novel model that recapitulates many features of the human disease. In the present study we compared the AAV-α-syn rat model with models where the nigro-striatal pathway is lesioned by injection of 6-OHDA in the striatum (partial lesion) or the medial forebrain bundle (full lesion). Examination of the behavioural changes over time revealed a different progression and magnitude of the motor impairment. Interestingly, dopamine (DA) neuron loss is prominent in both the toxin and the AAV-α-syn models. However, α-syn overexpressing animals were seen to exhibit less cell and terminal loss for an equivalent level of motor abnormalities. Prominent and persistent axonal pathology is only observed in the α-syn rat model. We suggest that, while neuronal and terminal loss mainly accounts for the behavioural impairment in the toxin-based model, similar motor deficits result from the combination of cell death and dysfunction of the remaining nigro-striatal neurons in the AAV-α-syn model. While the two models have been developed to mimic DA neuron deficiency, they differ in their temporal and neuropathological characteristics, and replicate different aspects of the pathophysiology of the human disease. This study suggests that the AAV-α-syn model replicates the human pathology more closely than either of the other two 6-OHDA lesion models.     

Do alpha-synuclein vector injections provide a better model of Parkinson's disease than the classic 6-hydroxydopamine model?

Improvements in modelling Parkinson's disease in rodents contribute to the advancement of scientific knowledge and open innumerable pathways for the development of new therapeutic interventions. In a recent article in this journal, Decressac and co-workers present an interesting comparison between two classic 6-hydroxydopamine (6-OHDA) models and the more recently established rodent model of Parkinson's disease induced by over-expression of α-synuclein using adeno-associated viral vectors. As expected, injections of 6-OHDA result in extensive loss of dopamine associated with pronounced motor deficits. Interestingly, over-expression of α-synuclein in the substantia nigra pars compacta also results in a considerable loss of dopamine as well as motor impairments. Both the level of dopamine loss and the motor deficits seen after α-synuclein over-expression were similar in extent to that seen after intrastriatal injections of 6-OHDA, but the temporal profile of degeneration and the development of motor deficits were progressive, more closely mimicking the clinical condition. This commentary offers further insights into the differences between these two rodent models, and asks how well they each replicate idiopathic PD. In addition, the translational relevance, reliability, and predictive value of this more recently developed AAV α-synuclein model are considered.     

Valproic Acid is Neuroprotective in the Rotenone Rat Model of Parkinson’s Disease: Involvement of α-Synuclein

Valproic acid (VPA), an established antiepileptic and antimanic drug, has recently emerged as a promising neuroprotective agent. Among its many cellular targets, VPA has been recently demonstrated to be an effective inhibitor of histone deacetylases. Accordingly, we have adopted a schedule of dietary administration (2% VPA added to the chow) that results in a significant inhibition of histone deacetylase activity and in an increase of histone H3 acetylation in brain tissues of 4 weeks-treated rats. We have tested this schedule of VPA treatment in an animal model of Parkinson’s disease (PD), in which degeneration of nigro-striatal dopaminergic neurons is obtained through sub-chronic administration of the mitochondrial toxin, rotenone, via osmotic mini pumps implanted to rats. The decrease of the dopaminergic marker tyrosine hydroxylase in substantia nigra and striatum caused by 7 days toxin administration was prevented in VPA-fed rats. VPA treatment also significantly counteracted the death of nigral neurons and the 50% drop of striatal dopamine levels caused by rotenone administration. The PD-marker protein α-synuclein decreased, in its native form, in substantia nigra and striatum of rotenone-treated rats, while monoubiquitinated α-synuclein increased in the same regions. VPA treatment counteracted both these α-synuclein alterations. Furthermore, monoubiquitinated α-synuclein increased its localization in nuclei isolated from substantia nigra of rotenone-treated rats, an effect also prevented by VPA treatment. Nuclear localization of α-synuclein has been recently described in some models of PD and its neurodegenerative effect has been ascribed to histone acetylation inhibition. Thus, the ability of VPA to increase histone acetylation is a novel candidate mechanism for its neuroprotective action.     

6-Hydroxydopamine-lesioning of the nigrostriatal pathway in rats alters basal ganglia mRNA for copper, zinc- and manganese-superoxide dismutase, but not glutathione peroxidase

The effects of nigrostriatal pathway destruction on the mRNA levels of copper, zinc-dependent superoxide dismutase (Cu,Zn-SOD), manganese-dependent superoxide dismutase (Mn-SOD), and glutathione peroxidase in basal ganglia of adult rat were investigated using in situ hybridization histochemistry and oligodeoxynucleotide (single-stranded complementary DNA) probes. The 6-hydroxydopamine (6-OHDA)-induced destruction of the nigrostriatal pathway resulted in contralateral rotation to apomorphine and a marked loss of specific [(3)H]mazindol binding in the striatum (93%; P<0.05) and of tyrosine hydroxylase mRNA in substantia nigra pars compacta (SC) (93%; P<0.05) compared with control rats. Levels of Cu,Zn-SOD mRNA were decreased in the striatum, globus pallidus, and SC on the lesioned side of 6-OHDA-lesioned rats compared with sham-lesioned rats (P<0.05). Levels of Mn-SOD mRNA were increased in the nucleus accumbens (P<0.05), but decreased in the SC (P<0.05) on the lesioned side of 6-OHDA-treated rats compared with sham-lesioned rats. Lesioning with 6-OHDA had no effect on glutathione peroxidase mRNA levels in any region of basal ganglia examined. The significant changes in Cu,Zn-SOD and Mn-SOD mRNA indicate that SOD is primarily expressed by dopaminergic neurons of the nigrostriatal pathway, and that the Mn-SOD gene appears to be inducible in rat basal ganglia in response to both physical and chemical damage 5 weeks after 6-OHDA-lesioning. These findings may clarify the status of antioxidant enzymes, particularly Mn-SOD, in patients with Parkinson's disease and their relevance to disease pathogenesis.     

Oral pelargonidin exerts dose-dependent neuroprotection in 6-hydroxydopamine rat model of hemi-parkinsonism

Parkinson's disease (PD) is a neuropathological and debilitating disorder involving the degeneration of mesencephalic dopaminergic neurons. Neuroprotective effect of pelargonidin (Pel) has already been reported, therefore, this study examined whether Pel administration would attenuate behavioural and structural abnormalities and markers of oxidative stress in an experimental model of PD in rat. For this purpose, unilateral intrastriatal 6-hydroxydopamine (6-OHDA, 12.5 μg/5 μl of saline-ascorbate)-lesioned rats were pre-treated p.o. with Pel (10 and/or 20 mg/kg). Pel administration dose-dependently attenuated the rotational behavior in lesioned rats and protected the neurons of SNC against 6-OHDA toxicity. In addition, pre-treatment with Pel (20 mg/kg) significantly decreased the 6-OHDA-induced thiobarbituric acid reactive substances (TBARS) formation, indicative of a neuroprotection against lipid peroxidation. Furthermore, the increase of nitrite levels induced by 6-OHDA, indicate the nitric oxide formation and free radicals production and the decrease of antioxidant defense enzyme superoxide dismutase (SOD) was non-significantly prevented by Pel (20 mg/kg). In summary, Pel administration has a dose-dependent neuroprotective effect against 6-OHDA toxicity, partly through attenuating oxidative stress. Our findings suggest that pelargonidin could provide benefits, along with other therapies, in neurodegenerative disorders including PD.     

Automated gait analysis in bilateral parkinsonian rats and the role of L-DOPA therapy

Gait disturbances and postural instability represent major sources of morbidity in Parkinson's disease (PD), and respond poorly to current treatment options. Some aspects of gait disturbances can be observed in rodent models of PD; however, knowledge regarding the stability of rodent gait patterns over time is lacking. Here we investigated the temporal constancy and reproducibility of gait patterns in neurologically intact and bilaterally 6-hydroxydopamine (6-OHDA) lesioned rats, by using an automated quantitative gait analysis method (CatWalk). The bilateral neurotoxin injections into the medial forebrain bundle resulted in an average dopamine (DA) loss of 70% in striatum, which corresponds to the DA levels observed in moderate-mid stage human PD. Rats were tested weekly during one month, and we found that in intact rats all parameters investigated remained constant over multiple tests. The 6-OHDA lesioned rats were impaired in several aspects of gait, such as stride length, swing speed, stance duration, step cycle duration, and base of support. However the stance and step cycle deficits were transient, the performance of 6-OHDA lesioned rats were indistinguishable from control rats by the last test session with regard to these parameters. Finally, we found that administration of a single dose of levodopa (l-DOPA) to the 6-OHDA lesioned rats could counteract all but one observed deficits. Based on these findings we conclude that the gait pattern of intact rats is highly reproducible, 6-OHDA lesioned rats display impairments in gait, and l-DOPA can counteract most deficits seen in this model of experimental PD.