Rotenone Administration Research Articles

Dihydroxyphenylacetaldehyde Lowering Treatment Improves Locomotor and Neurochemical Abnormalities in the Rat Rotenone Model: Relevance to the Catecholaldehyde Hypothesis for the Pathogenesis of Parkinson's Disease.

The catecholaldehyde hypothesis for the pathogenesis of Parkinson's disease centers on accumulation of 3,4-dihydroxyphenylacetaldehyde (DOPAL) in dopaminergic neurons. To test the hypothesis, it is necessary to reduce DOPAL and assess if this improves locomotor abnormalities. Systemic administration of rotenone to rats reproduces the motor and central neurochemical abnormalities characterizing Parkinson's disease. In this study, we used the monoamine oxidase inhibitor (MAOI) deprenyl to decrease DOPAL production, with or without the antioxidant N-acetylcysteine (NAC). Adult rats received subcutaneous vehicle, rotenone (2 mg/kg/day via a minipump), or rotenone with deprenyl (5 mg/kg/day i.p.) with or without oral NAC (1 mg/kg/day) for 28 days. Motor function tests included measures of open field activity and rearing. Striatal tissue was assayed for contents of dopamine, DOPAL, and other catechols. Compared to vehicle, rotenone reduced locomotor activity (distance, velocity and rearing); increased tissue DOPAL; and decreased dopamine concentrations and inhibited vesicular sequestration of cytoplasmic dopamine and enzymatic breakdown of cytoplasmic DOPAL by aldehyde dehydrogenase (ALDH), as indicated by DA/DOPAL and DOPAC/DOPAL ratios. The addition of deprenyl to rotenone improved all the locomotor indices, increased dopamine and decreased DOPAL contents, and corrected the rotenone-induced vesicular uptake and ALDH abnormalities. The beneficial effects were augmented when NAC was added to deprenyl. Rotenone evokes locomotor and striatal neurochemical abnormalities found in Parkinson's disease, including DOPAL buildup. Administration of an MAOI attenuates these abnormalities, and NAC augments the beneficial effects. The results indicate a pathogenic role of DOPAL in the rotenone model and suggest that treatment with MAOI+NAC might be beneficial for Parkinson's disease treatment.

Downregulation of PACAP and the PAC1 Receptor in the Basal Ganglia, Substantia Nigra and Centrally Projecting Edinger-Westphal Nucleus in the Rotenone model of Parkinson's Disease.

Numerous in vitro and in vivo models of Parkinson's disease (PD) demonstrate that pituitary adenylate cyclase-activating polypeptide (PACAP) conveys its strong neuroprotective actions mainly via its specific PAC1 receptor (PAC1R) in models of PD. We recently described the decrease in PAC1R protein content in the basal ganglia of macaques in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD that was partially reversed by levodopa therapy. In this work, we tested whether these observations occur also in the rotenone model of PD in the rat. The rotarod test revealed motor skill deterioration upon rotenone administration, which was reversed by benserazide/levodopa (B/L) treatment. The sucrose preference test suggested increased depression level while the open field test showed increased anxiety in rats rendered parkinsonian, regardless of the received B/L therapy. Reduced dopaminergic cell count in the substantia nigra pars compacta (SNpc) diminished the dopaminergic fiber density in the caudate-putamen (CPu) and decreased the peptidergic cell count in the centrally projecting Edinger-Westphal nucleus (EWcp), supporting the efficacy of rotenone treatment. RNAscope in situ hybridization revealed decreased PACAP mRNA (Adcyap1) and PAC1R mRNA (Adcyap1r1) expression in the CPu, globus pallidus, dopaminergic SNpc and peptidergic EWcp of rotenone-treated rats, but no remarkable downregulation occurred in the insular cortex. In the entopeduncular nucleus, only the Adcyap1r1 mRNA was downregulated in parkinsonian animals. B/L therapy attenuated the downregulation of Adcyap1 in the CPu only. Our current results further support the evolutionarily conserved role of the PACAP/PAC1R system in neuroprotection and its recruitment in the development/progression of neurodegenerative states such as PD.

Caffeine alleviates anxiety-like behavior and brainstem lesions in a rotenone-induced rat model of Parkinson's disease

BackgroundParkinson's disease (PD) is a neurodegenerative disorder characterized by motor and non-motor symptoms. In 2016, approximately 6.1 million individuals were affected by PD, with 211,296 deaths attributed to the disease. The understanding of PD initially came from the observation of dopaminergic system alterations in a specific region of the brainstem, indicating that the core motor and non-motor features of PD are closely associated with brainstem dysfunction. The primary treatment approach for PD revolves around dopamine replacement, as many of the symptoms are responsive to this therapeutic intervention. However, long-term administration of this approach is linked to several complications, and a definitive gold-standard therapy for PD is yet to be identified. The pharmacological management of PD has been challenging and inconsistent, mainly due to the unclear underlying cause of the disease. This study aims to evaluate the effects of caffeine on the brainstem of rats with PD induced by rotenone. MethodologyFifty adult male Wistar rats weighing between 150 and 200 g were used in this study. The rats were randomly divided into five groups of ten rats each: Vehicle Group, Rotenone-only treated Group (rotenone only treated with 3 mg/kg, intraperitoneal administration [IP]), Preventive Group (caffeine 30 mg/kg + rotenone 3 mg/kg, IP), Curative Group (rotenone 3 mg/kg + caffeine 30 mg/kg, IP), and Caffeine only treated Group (caffeine only treated with 30 mg/kg, IP). The animals underwent neurobehavioral assessments, followed by sacrifice. The brains were then excised, weighed, and processed histologically. Appropriate brain sections were taken and processed. Photomicrographs were obtained, morphometric and statistical analysis was performed using an Omax LED digital ResultsThe results demonstrated a significant (p < 0.05) reduction in body weight and relative brain weight, which were increased by caffeine treatments. Rotenone administration led to histological changes similar to those observed in PD, including neuronal structural derangement, degenerated nerve fibers, loss of myelinated neurons, and Nissl substance, as well as downregulation in the expressions of NRF2 and TH in the midbrain. However, these pathological features were counteracted or ameliorated by caffeine treatment. ConclusionOur study contributes additional evidence to the growing body of research supporting the therapeutic potential of caffeine in Parkinson's disease (PD). The results underscore the neuroprotective properties of caffeine and its capacity to mitigate oxidative stress by modulating TH (tyrosine hydroxylase) and cytoplasmic NRF2 (nuclear factor erythroid 2-related factor 2) in the mesencephalon. These findings suggest that caffeine holds promise as a viable treatment option for PD.

MRNA level of antioxidant genes and activity of NADPH-generating enzymes in rotenone-induced parkinsonism in rats

Aim. To analyze the mRNA level of genes encoding antioxidant enzymes and the transcription factors Nrf2 and Foxo1 regulating their expression and the activity of glucose-6-phosphate dehydrogenase (G6PDH) and NADPdependent isocitrate dehydrogenase (NADP-IDH) and assess the correlation between these parameters, oxidative status, and motor coordination parameters in rats with rotenone-induced parkinsonism.Materials and methods. The study was performed on male Wistar rats aged 4–6 months and weighing 200–250 g. Parkinsonism was modeled by subcutaneous administration of rotenone for 10 days at a dose of 2.5 mg / kg. To confirm the development of the pathology, motor coordination tests and histological staining of the cerebral cortex and striatum with hematoxylin and eosin were used. The oxidative status was analyzed based on the levels of conjugated dienes, carbonyl amino acid residues in proteins, and α-tocopherol. The enzyme activity was studied spectrophotometrically by the formation of NADPH. Real-time PCR was used to analyze the level of gene mRNA.Results. During the study, an increase in serum and brain concentrations of conjugated dienes, carbonyl amino acid residues, and α-tocopherol was observed in the experimental group of rats compared to the controls. It could be associated with the redistribution of this compound between tissues during pathology development. The animals with experimental parkinsonism, in addition, were characterized by a decrease in the mRNA level of the Sod1, Gpx1, Gsr, Gsta2, Nfe2l2, and Foxo1 genes, as well as the activity of G6PDH and NADP-IDH. In the rats with experimental parkinsonism, a negative correlation of NADPH-IDH activity in the brain with serum α-tocopherol level and a positive correlation with Gpx1 and Foxo1 mRNA levels in the striatum were found. The level of oxidatively modified proteins in the brain of the animals with PD was negatively correlated with the concentration of Gsta2 mRNA in the striatum, while the specific activity of G6PDH in the serum was characterized by the positive relationship with grip strength.Conclusion. The data obtained indicate that the inhibition of transcription of the genes encoding antioxidant enzymes and regulatory factors Nrf2 and Foxo1 contributed significantly to the development of oxidative stress in PD. A decrease in the activity of G6PDH and NADP-IDH led to a decrease in the availability of NADPH, which is a limiting factor in the functioning of the glutathione antioxidant system. Obviously, the inhibition of G6PDH and NADP-IDH was also an important pathogenic factor in the progression of the pathology. Along with a decrease in the content of antioxidant gene mRNA in the brain tissues, the level of α-tocopherol increased in the rats with parkinsonism, which could be the result of an imbalance in the functioning of antioxidant system.

Delayed in sensorimotor reflex ontogeny, slow physical growth, and impairments in behaviour as well as dopaminergic neuronal death in mice offspring following prenatally rotenone administration.

The environment is varying day by day with the introduction of chemicals such as pesticides, most of which have not been effectively studied for their influence on a susceptible group of population involving infants and pregnant females. Rotenone is an organic pesticide used to prepare Parkinson's disease models. A lot of literature is available on the toxicity of rotenone on the adult brain, but to the best of our knowledge, effect of rotenone on prenatally exposed mice has never been investigated yet. Therefore, the recent work aims to evaluate the toxic effect of rotenone on mice, exposed prenatally. We exposed female mice to rotenone at the dose of 5mg/Kg b.w. throughout the gestational period with oral gavage. We then investigated the effects of rotenone on neonate's central nervous systems as well as on postnatal day (PD) 35 offspring. In the rotenone group, we observed slow physical growth, delays in physical milestones and sensorimotor reflex in neonates and induction of anxiety and impairment in cognitive performances of offspring at PD-35. Additionally, immunohistochemical analysis revealed a marked reduction in TH-positive neurons in substantia nigra. Histological examination of the cerebellum revealed a decrease in Purkinje neurons in the rotenone exposed group as compared to the control. The data from the study showed that prenatally exposure to rotenone affects growth, physical milestones, neuronal population and behaviour of mice when indirectly exposed to the offspring through their mother. This study could provide a great contribution to researchers to find out the molecular mechanism and participating signalling pathway behind these outcomes.

Формування ультраструктурних адаптивних реакцій у тканинах організму при експериментальному паркінсонізмі

We studied changes in the ultrastructure of brain tissues - medulla oblongata and striatum, as well as lung and heart tissues in experimental parkinsonism caused by the action of rotenone, which was administered once or for 2 weeks. It has been shown that during the development of a Parkinson-like state the ultrastructure of tissues disturbance, the development of mitochondrial and endothelial dysfunction is observed not only in parts of the brain, but also in other tissues of the body. Mitochondrial dysfunction is significantly expressed in the medulla oblongata, as evidenced by, firstly, a decrease in the total number of mitochondria by 35.7%, and secondly, damage to their ultrastructure in more than 40% of organelles. Endothelial dysfunction was indicated by hyperhydration of the blood-brain barrier. In the tissue of the striatum, the indicated changes were insignificant, instead, a compensatory restoration of dynamic processes in the mitochondrial apparatus, in particular fission-fusion processes, was observed. In the myocardium, there were also significant changes in the ultrastructure, this indicated the development of both mitochondrial and endothelial dysfunctions. As well as in the medulla oblongata tissue, about 40% of mitochondria were found to be damaged, although it should be noted that although not pronounced, but still reliable (by 12.6%) activation of mitochondrial morphogenesis was observed. The histohematal barrier, in particular its endothelial layer, thinned due to destructive processes. Violations of the ultrastructure were also observed in the lung tissue. Significant changes in the mitochondrial apparatus with damage to the mitochondrial structure were revealed. However, the percentage of structurally damaged organelles was significantly (almost 2 times) lower than in the myocardium (reached only 25%). The thickness of the endothelial layer of the air barrier increased by an average of 30%. In tissues where mitochondrial and endothelial dysfunction were less pronounced during longterm administration of rotenone, adaptive changes begin to form, which are probably also observed in people with Parkinson’s disease, which enables them to adapt to the existing disease.

Expression of Nuclear Factor – kappa B (NF-kB) in Human Breast Cancer Stem Cells (CD 24-/CD 44+) Treated with H2O2 and Its Relationship with Cell Viability

Introduction: Breast cancer is one of the highest causes of death from cancer in women in Indonesia. This is partly due to the resistance of ROS-based therapies such as radiotherapy and chemotherapy. Breast cancer stem cells (cancer stem cells, CSCs) have a role in this resistance mechanism. Previous studies demonstrated the ability of CSC to survive oxidative stress conditions due to rotenone administration. Therefore, in this study an analysis was carried out on the transcription factor NF-kB in breast cancer cells, both CSCs and Non CSCs, related to the role of NF-kB in maintaining the survival of cancer cells under conditions of oxidative stress. Methods: The study was conducted on human breast cancer stem cells (CD24-/CD44+) and non stem cells (CD24-/CD44-) which were given H2O2 at concentrations of 1.1µM, 11µM, and 110µM with control cells not given H2O2. Assessment was carried out on the parameters of NF-kB mRNA expression, and cell viability. Results: Administration of H2O2 at a concentration of 11µM showed a significant increase in the expression of NFk-B CSCs mRNA compared to non CSCs (p&lt;0.05). As for the viability test results, at all concentrations of H2O2 it appears that CSCs was able to maintain its viability compared to non CSCs which experienced a decrease in viability (p&lt;0.05). Conclusion: In this study, conditions of oxidative stress due to the administration of H2O2 led to an increase in the expression of NF-kB mRNA in CSCs so that cell viability could be maintained.

Cytoprotective and anti-inflammatory effect of ethanolic extract of Withania somnifera root in combination with doxycycline in rotenone induced cytotoxicity in neuroblastoma cell lines

Introduction and Aim: Parkinson's disease (PD) is a neurodegenerative disorder that destroys dopaminergic neurons in the nigrostriatal area of the midbrain this results in a movement difficulty characterised by tremors, bradykinesia, and postural instability The present in vitro study is designed to assess the beneficial (cytoprotectant and anti-inflammatory) and cyto-toxicological effects of ethanolic Withania somnifera (Ashwagandha) root extract (EWSR) in presence of Rotenone (ROT) and other known neuroprotectants (Doxycycline and Ellagic acid). Materials and Methods: The nine groups used in the in vitro studies were normal control, positive control (Rotenone or Rot), W. somnifera root extract (EWSR), Doxycycline (Doxy), Ellagic acid (EA), ROT with EWSR, ROT with doxy, ROT with EA, ROT with EWSR-doxy, and ROT with EWSR-doxy-EA. The EWSR, doxy and EA treatment was started on the 24th hour following the rotenone administration and continued for the next 36 hours. After the 36th hour of protective therapy, quantification of pro-inflammatory cytokines (ELISA), cell viability or analyses of neuronal cell loss, cell cycle analysis and molecular analysis (RTPCR) was performed as a part of assessment. Results: Observations from the present in vitro studies clearly demonstrate the cytoprotective and anti-inflammatory properties of EWSR, and these beneficial or protective effects got enhanced when treated in combination with Doxy and EA indicating synergistic effect in the cells that were priorly treated with ROT, and later treated with EWSR, Doxy, and EA individually and in combination. Conclusion: The findings imply that EWSR reduces the in vitro effects of ROT by acting as an anti-inflammatory and cytoprotective agent.

Metabolic dysfunctions in the intranigral rotenone model of Parkinson's disease.

Parkinson disease (PD) is a chronic neurodegenerative disorder characterized by a progressive loss of dopamine neurons in the substantia nigra pars compacta(SNpc). In the last years, a growing interest to study the relationship between metabolic dysfunction and neurodegenerative disease like PD has emerged. This study aimed to evaluate the occurrence of possible changes in metabolic homeostasis due to intranigral rotenone administration, a neurotoxin that damages dopaminergic neurons leading to motor impairments mimicking those that happen in PD. Male Wistar rats were distributed into two groups: sham (n = 10) or rotenone (n = 10). Sham group received, bilaterally, within the SNpc, 1 µL of vehicle dimethyl-sulfoxide (DMSO) and the experimental group was bilaterally injected with 1 µL of rotenone (12µg/µL). Twenty-four hours after the stereotaxic surgeries, the animals underwent the open field test followed by subsequent peripheral blood and cerebrospinal fluid (CSF) samples collection for biochemical testing. The results showed that rotenone was able to replicate the typical motor behavior impairment seen in the disease, i.e., decrease in locomotion (P = 0.05) and increase in immobility (P = 0.01) with a strong correlation (r = -0.85; P < 0.0001) between them. In addition, it was demonstrated that this model is able to decrease plasmatic total-cholesterol (P = 0.04) and HDL-cholesterol (P = 0.007) potentially impacting peripheral metabolism. Hence, it was revealed a potential ability to reproduce relevant metabolic dysfunctions like hyperglycemia which could be explained by acute and systemic mitochondrial rotenone toxicity and SNpcnigral toxicity. Such mechanisms may still be responsible for the potential occurrence of CSF-hyperglycemia (d = 0.7). Since intranigral rotenone is an early phase model of PD, the present results open a new road for studies aiming to investigate metabolic changes in PD.

Myrcene Salvages Rotenone-Induced Loss of Dopaminergic Neurons by Inhibiting Oxidative Stress, Inflammation, Apoptosis, and Autophagy.

Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta, resulting in motor deficits. The exact etiology of PD is currently unknown; however, the pathological hallmarks of PD include excessive production of reactive oxygen species, enhanced neuroinflammation, and overproduction of α-synuclein. Under normal physiological conditions, aggregated α-synuclein is degraded via the autophagy lysosomal pathway. However, impairment of the autophagy lysosomal pathway results in α-synuclein accumulation, thereby facilitating the pathogenesis of PD. Current medications only manage the symptoms, but are unable to delay, prevent, or cure the disease. Collectively, oxidative stress, inflammation, apoptosis, and autophagy play crucial roles in PD; therefore, there is an enormous interest in exploring novel bioactive agents of natural origin for their protective roles in PD. The present study evaluated the role of myrcene, a monoterpene, in preventing the loss of dopaminergic neurons in a rotenone (ROT)-induced rodent model of PD, and elucidated the underlying mechanisms. Myrcene was administered at a dose of 50 mg/kg, 30 min prior to the intraperitoneal injections of ROT (2.5 mg/kg). Administration of ROT caused a considerable loss of dopaminergic neurons, subsequent to a significant reduction in the antioxidant defense systems, increased lipid peroxidation, and activation of microglia and astrocytes, along with the production of pro-inflammatory cytokines (IL-6, TNF-α, IL-1β) and matrix metalloproteinase-9. Rotenone also resulted in impairment of the autophagy lysosomal pathway, as evidenced by increased expression of LC3, p62, and beclin-1 with decreased expression in the phosphorylation of mTOR protein. Collectively, these factors result in the loss of dopaminergic neurons. However, myrcene treatment has been observed to restore antioxidant defenses and attenuate the increase in concentrations of lipid peroxidation products, pro-inflammatory cytokines, diminished microglia, and astrocyte activation. Myrcene treatment also enhanced the phosphorylation of mTOR, reinstated neuronal homeostasis, restored autophagy-lysosomal degradation, and prevented the increased expression of α-synuclein following the rescue of dopaminergic neurons. Taken together, our study clearly revealed the mitigating effect of myrcene on dopaminergic neuronal loss, attributed to its potent antioxidant, anti-inflammatory, and anti-apoptotic properties, and favorable modulation of autophagic flux. This study suggests that myrcene may be a potential candidate for therapeutic benefits in PD.

Co-Administration of Vitamins B12 and D During Pregnancy Have Strong Neuroprotective Effects in Parkinson Disease.

Parkinson's disease (PD) is a common disease whose pathophysiological mechanism is not well understood. Recent research studies have shown that PD patients have low serum levels of vitamins B12 and D. Therefore, in this study, the effects of supplementation with vitamins B12 and D on PD female mice as well as their fetuses were studied. After preparation of female mice and induction of Parkinson's by rotenone administration for 19days, rotarod test was used to confirm PD induction. During this time, supplementations with vitamins B12 and D were performed. On day 19, after confirmation of PD induction, half of the mice were killed and the other half were allowed to mate with males. Viability was measured by the MTT method, and apoptosis and necrosis of cerebellar neurons were measured by flow cytometry. The RT-PCR technique was used to evaluate the relative expressions of the bax, bcl-2, miR-211, and circRNA 0,001,518 genes. Data analysis was performed by the GraphPad Prism V.8 software. Co-administration of vitamins B12 and D resulted in highest viability percentage and greatest reduction in apoptosis and necrosis of cerebellar neurons in the female mice as well as their fetuses compared to the PD females. A decrease in the relative expression of the bax and miR-211 genes and an increase in bcl-2 expression were observed in the cerebellar tissue of PD mice receiving both vitamins. Vitamins B12 and D have neuroprotective effects on PD conditions. Therefore, co-administration of these two vitamins is recommended in PD patients during pregnancy.

Neuroprotective effects of isatin and afobazole in rats with rotenone-induced Parkinsonism are accompanied by increased brain levels of Triton X-100 soluble alpha-synuclein.

Effects of the endogenous neuroprotector isatin and the pharmacological drug afobazole (exhibiting neuroprotective properties) on behavioral reactions and quantitative changes in the brain proteomic profile have been investigated in rats with experimental rotenone Parkinsonism. A single dose of isatin (100 mg/kg subcutaneously on the last day of a 7-day course of rotenone administration) improved the motor activity of rats with rotenone-induced Parkinsonism in the open field test (horizontal movements) and the rotating rod test. Afobazole (10 mg/kg intraperitoneally, daily during the 7-day course of rotenone administration) reduced the manifestations of rigidity and postural instability. Proteomic analysis, performed using brain samples obtained the day after the last administration of rotenone and neuroprotectors, revealed similar quantitative changes in the brain of rats with rotenone Parkinsonism. An increase in the relative content of 65 proteins and a decrease in the relative content of 21 proteins were detected. The most pronounced changes - an almost ninety-fold increase in the alpha-synuclein content - were found in the brains of rats treated with isatin. In animals of the experimental groups treated with "Rotenone + Isatin", as well as "Rotenone + Afobazole", the increase in the relative content of this protein in the brain was almost 60 and 50 times higher than the control values. Taking into consideration the known data on the physiological role of alpha-synuclein, an increase in the content of this protein in the brain upon administration of neuroprotectors to animals with rotenone Parkinsonism may represent a compensatory reaction, at least in the early stages of this disease and the beginning of its treatment.

Neuroprotective effect of secukinumab against rotenone induced Parkinson's disease in rat model: Involvement of IL-17, HMGB-1/TLR4 axis and BDNF/TrKB cascade.

Neuroinflammatory status produced via activation of toll like receptor-4 (TLR-4) and interleukin-17 receptor (IL-17R) is one of the principal mechanisms involved in dopaminergic neuronal loss in Parkinson's disease (PD). Activation of TLR-4 and IL-17R stimulates reactive oxygen species (ROS) and proinflammatory cytokines (IL-17, IL-1β, TNFα, IL-6) production that augments neurodegeneration and reduces neuro-survival axis (TrKB/Akt/CREB/BDNF). So, reducing IL-17-driven neuroinflammation via secukinumab, monoclonal antibody against IL-17A, may be one of therapeutic approach for PD. Moreover, the aim was extended to delineate the possible neuroprotective mechanism involved against neuronal loss in rotenone induced PD in rats. Rats received 11 subcutaneous injection of rotenone (1.5mg/kg) every other day for 21 consecutive days and treated with 2 subcutaneous injections of secukinumab (15mg/kg) on day 9 and 15, one hour after rotenone administration. Treatment with secukinumab improved motor impairment and muscle incoordination induced by rotenone, as verified by open field and rotarod tests. Moreover, secukinumab attenuated neuronal loss and improve histopathological profile. Noteworthy, secukinumab reduces neuro-inflammatory status by hindering the interaction between IL and 17A and IL-17RA together with inhibiting the activation of TLR-4 and its downstream cascade including pS536-NFκB p65, IL-1β and HMGB-1. Additionally, secukinumab stimulated neuro-survival signalling cascade via activation pY515-TrKB receptor and triggered upsurge in its downstream targets (pS473-Akt/pS133-CREB/BDNF). Furthermore, secukinumab increased striatal tyrosine hydroxylase immunoexpression, the rate limiting step in dopamine biosynthesis, to guard against dopaminergic neuronal loss. In conclusion, secukinumab exerts a neuroprotective effect against rotenone induced neuronal loss via inhibition IL17A/IL17RA interaction and HMGB-1/TLR-4/NF-κBp65/IL1β signalling cascade, together with activation of TrKB/ Akt/CREB/BDNF axis.

Intranasal Rotenone Induces Alpha-Synuclein Accumulation, Neuroinflammation and Dopaminergic Neurodegeneration in Middle-Aged Mice.

Accumulation of alpha-synuclein (α-syn) is central to the pathogenesis of Parkinson's disease (PD). Previous studies suggest that α-syn pathology may originate from the olfactory bulb (OB) or gut in response to an unknown pathogen and later progress to the different brain regions. Aging is viewed as the utmost threat to PD development. Therefore, studies depicting the role of age in α-syn accumulation and its progression in PD are important. In the present study, we gave intranasal rotenone microemulsion for 6weeks in 12-month-old female BALB/c mice and found olfactory dysfunction after 4 and 6weeks of rotenone administration. Interestingly, motor impairment was observed only after 6weeks. The animals were sacrificed after 6weeks to perform western blotting and immunohistochemical studies to detect α-synpathology, neuroinflammation and neurodegeneration. We found α-syn accumulation in OB, striatum, substantia nigra (SN) and cortex. Importantly, we found significant glial cell activation and neurodegeneration in all the analysed regions which were absent in our previous published studies with 3months old mice even after they were exposed to rotenone for 9weeks indicating age is a crucial factor for α-syn induced neuroinflammation and neurodegeneration. We also observed increased iron accumulation in SN of rotenone-exposed aged mice. Moreover, inflammaging was observed in OB and striatum of 12-month-old BALB/c mice as compared to 3-month-old BALB/c mice. In conclusion, there is a difference in sensitivity between adult and aged mice in the development and progression of α-syn pathology and subsequent neurodegeneration, for which inflammaging might be the crucial probable mechanism.

Trans-cinnamaldehyde mitigates rotenone-induced neurotoxicity via inhibiting oxidative stress in rats

BackgroundThe second most prevalent age-related brain condition, Parkinson's disease (PD) is characterised by the loss of neurons in the substantia nigra pars compacta (SNpc). It is associated with symptoms like bradykinesia, stiffness, tremor, and impaired postural responses. Motor dysfunction, and neurochemical imbalance, are involved in the pathophysiology of PD. It has been hypothesised that trans cinnamaldehyde (TCA) a component of Traditional Chinese Medicine (TCM) can ameliorate Parkinson-like symptoms by altering the levels of different biochemical markers and reverse motor impairments. This research sought to determine the neuroprotective effect of TCA against the neurotoxicity caused by rotenone. Basic ProcedureRotenone (1.5 mg/kg/day; s.c. for 35 days) was given to rats to induce Parkinson-like symptoms. TCA (5, 10, and 20 mg/kg) and concomitant treatment of TCA (5 mg/kg) with L-NAME (10 mg/kg) were given one hour prior to rotenone administration. Every week until the 35th day, behavioral parameters (muscle coordination, spontaneous motor movement and gait abnormalities) were assessed using rotarod, actophotometer, and narrow beam apparatus respectfully. Rats were decapitated on the 35th day, the striatum and cortex were isolated for biochemical tests. Main findingsRotenone treatment reduced body weight, altered motor coordination and reduced the oxidative defense system. Treatment with TCA significantly improved the alterations in antioxidant levels as well as behavioral parameters. Furthermore, L-NAME (nitric oxide synthase inhibitor) in combination with TCA had a more significant effect as compared to TCA alone, signifying a possible drug interaction. Principal conclusionTCA could be employed as an adjuvant in PD management.

Folic Acid and Vitamin B12 Prevent Deleterious Effects of Rotenone on Object Novelty Recognition Memory and Kynu Expression in an Animal Model of Parkinson's Disease.

Parkinson's disease (PD) is characterized by a range of motor signs, but cognitive dysfunction is also observed. Supplementation with folic acid and vitamin B12 is expected to prevent cognitive impairment. To test this in PD, we promoted a lesion within the substantia nigra pars compacta of rats using the neurotoxin rotenone. In the sequence, the animals were supplemented with folic acid and vitamin B12 for 14 consecutive days and subjected to the object recognition test. We observed an impairment in object recognition memory after rotenone administration, which was prevented by supplementation (p &lt; 0.01). Supplementation may adjust gene expression through efficient DNA methylation. To verify this, we measured the expression and methylation of the kynureninase gene (Kynu), whose product metabolizes neurotoxic metabolites often accumulated in PD as kynurenine. Supplementation prevented the decrease in Kynu expression induced by rotenone in the substantia nigra (p &lt; 0.05), corroborating the behavioral data. No differences were observed concerning the methylation analysis of two CpG sites in the Kynu promoter. Instead, we suggest that folic acid and vitamin B12 increased global DNA methylation, reduced the expression of Kynu inhibitors, maintained Kynu-dependent pathway homeostasis, and prevented the memory impairment induced by rotenone. Our study raises the possibility of adjuvant therapy for PD with folic acid and vitamin B12.

Systemic Rotenone Administration Causes Extra-Nigral Alterations in C57BL/6 Mice.

Systemic administration of rotenone replicates several pathogenic and behavioural features of Parkinson's disease (PD), some of which cannot be explained by deficits of the nigrostriatal pathway. In this study, we provide a comprehensive analysis of several neurochemical alterations triggered by systemic rotenone administration in the CNS of C57BL/6 mice. Mice injected with either 1, 3 or 10 mg/kg rotenone daily via intraperitoneal route for 21 days were assessed weekly for changes in locomotor and exploratory behaviour. Rotenone treatment caused significant locomotor and exploratory impairment at dosages of 3 or 10 mg/kg. Molecular analyses showed reductions of both TH and DAT expression in the midbrain, striatum and spinal cord, accompanied by altered expression of dopamine receptors and brain-derived neurotrophic factor (BDNF). Rotenone also triggered midbrain-restricted inflammatory responses with heightened expression of glial markers, which was not seen in extra-nigral regions. However, widespread alterations of mitochondrial function and increased signatures of oxidative stress were identified in both nigral and extra-nigral regions, along with disruptions of neuroprotective peptides, such as pituitary adenylate cyclase-activating polypeptide (PACAP), vasoactive intestinal peptide (VIP) and activity-dependent neuroprotective protein (ADNP). Altogether, this study shows that systemic rotenone intoxication, similarly to PD, causes a series of neurochemical alterations that extend at multiple CNS levels, reinforcing the suitability of this pre-clinical model for the study extra-nigral defects of PD.

Pharmacological approach using doxycycline and tocopherol in rotenone induced oxidative stress, neuroinflammation and Parkinson’s like symptoms

Background Parkinson’s disease (PD) is a second most common neurodegenerative disorder characterized by the selective and progressive degeneration of dopaminergic neurons in substantia nigra pars compacta. Rotenone is a neurotoxin which selectively degenerate dopaminergic neurons in striatum, leading to cause PD like symptoms. Method Rotenone was administered at a dose of 1.5 mg/kg, i.p. from day 1 to day 40. Treatment with doxycycline (50 and 100 mg/kg, p.o), tocopherol (5 mg and 10 mg/kg, p.o) alone, doxycycline (50 mg/kg, p.o) in combination with tocopherol (10 mg/kg, p.o), and ropinirole (0.5 mg/kg, i.p.) was given for 40 days 1 h prior to administration of rotenone. All behavioral parameters were analyzed on weekly basis. On day 41, animals were sacrificed and the striatum region was isolated for neurotransmitters estimation (dopamine, serotonin, norepinephrine, GABA and glutamate), biochemical analysis (GSH, nitrite, LPO, mitochondrial complexes I and IV), inflammatory markers estimation (IL-6, IL-1β and TNF-α) and activity of MAO-A, MAO-B. Result Doxycycline and tocopherol in combination significantly attenuated behavioral, neurotransmitters and biochemical alterations induced by rotenone in experimental rats as compared to alone treatment with DOX and TOCO. Similarly, DOX and TOCO combination significantly reduced the level of inflammatory markers, prevented the biochemical changes, decreased MAO-A and MAO-B and improved complex-I, complex-IV, cAMP levels significantly. Conclusion The current study revealed that a combination of doxycycline with tocopherol contributed to the prevention of PD like symptoms in rats by antioxidant, anti-inflammatory, MAO inhibitory and neuromodulatory mechanisms.

Empagliflozin enhances neuroplasticity in rotenone-induced parkinsonism: Role of BDNF, CREB and Npas4

AimsParkinsonism is characterized by degeneration of dopaminergic neurons and impairment in neuroplasticity. Empagliflozin (EMPA) is an anti-diabetic drug that has been shown to improve cognitive dysfunctions and exerted antioxidant and anti-inflammatory effects in different models. This study aimed to determine the neuroprotective effects of EMPA against rotenone (ROT)-induced parkinsonism. Main methodsROT (1.5 mg/kg) was injected subcutaneously three times per week for two successive weeks. Mice were treated with EMPA (3 and 10 mg/kg, orally) for one week prior ROT administration and for another two weeks along with ROT. After that, motor functions and histopathological changes were assessed, and brains were isolated for biochemical analyses and immunohistochemical investigation. Key findingsResults indicated that, in a dose dependent manner, EMPA improved motor functions and histopathological changes induced by ROT, increased brain content of reduced glutathione (GSH), dopamine (DA), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), nuclear factor erythroid 2–related factor 2 (Nrf2), inositol trisphosphate (IP3), calcium (Ca2+), calcium/calmodulin-dependent protein kinase type IV (CaMKIV) and phospho-Protein kinase B (p-Akt) levels compared to ROT group. Additionally, EMPA decreased the levels of malondialdehyde (MDA), and tumor necrosis factor-α (TNF-α), and inactivated glycogen synthase kinase-3 beta (GSK-3β). Improvement in neuroplasticity was also observed indicated by elevation in brain derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), and neuronal PAS domain Protein 4 (Npas4). SignificanceEMPA improved motor functions possibly through improving neuroplasticity markers and antioxidant, anti-inflammatory, and neuroprotective effects in a dose dependent manner.

Changes in glial cells and neurotrophic factors due to rotenone-induced oxidative stress in Nrf2 knockout mice

Glaucoma is one of the most common causes of blindness worldwide. It is thought to be a multifactorial disease with underlying mechanisms that include mitochondrial dysfunction and oxidative stress. Here, we used NF-E2 related factor 2 (Nrf2) knockout (KO) mice, which are vulnerable to oxidative stress, to examine a neuroprotective effect against oxidative stress due to rotenone, a mitochondrial complex I inhibitor. Wild-type (WT) and Nrf2 KO mice received an oral solution of rotenone for 30 days. We then extracted the retinas and performed immunohistochemistry and quantitative RT-PCR. We also prepared a primary Müller cell culture of samples from each mouse, added 30 μM rotenone, and then measured cell viability, cytotoxicity and CellRox absorbance. We also examined gene expression. We found a significant increase in the number of 8-OHdG-positive retinal ganglion cells (RGCs) after rotenone administration in both the WT and Nrf2 KO mice. There was no difference in the number of RNA-binding protein with multiple splicing (RBPMS)-positive RGCs in the WT and Nrf2 KO mice, but Nrf2 KO mice that were given rotenone had significantly less retinal gene expression of RBPMS than Nrf2 KO mice given a control. Moreover, there was significantly higher mRNA gene expression of vimentin and glial fibrillary acidic protein (GFAP) in Nrf2 KO mice that received rotenone than WT mice that received rotenone. A statistical analysis of the in vitro experiment showed that cell viability was lower, cytotoxicity was higher, and oxidative stress was higher in the Müller cells of the Nrf2 KO mice than the WT mice. Finally, brain-derived neurotrophic factor (BDNF) and basic fibroblast growth factor (bFGF) were significantly higher in the Müller cells of the Nrf2 KO mice than the WT mice. These findings suggest that in Nrf2 KO mice under oxidative stress caused by rotenone, temporary neurotrophic factors are secreted from the Müller cells, conferring neuroprotection in these cells.