Effect of Buspirone, Fluoxetine and 8-OH-DPAT on Striatal Expression of Bax, Caspase-3 and Bcl-2 Proteins in 6-Hydroxydopamine-Induced Hemi-Parkinsonian Rats

How do HCN channels play a part in Alzheimer's and Parkinson's disease?

Neurodegenerative diseases like Alzheimer's and Parkinson's disease (AD and PD) are well-known, yet their underlying causes remain unclear. Recent studies have suggested that disruption of ion channels contribute to their pathogenesis. Among these channels, the hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, encoded by HCN1-4 genes, are of particular interest due to their role in generating hyperpolarization-activated current (Ih), which is crucial in various neural activities impacting memory and motor functions. A growing body of evidence underscores the pivotal role of HCN in Aβ generation, glial cell function, and ischemia-induced dementia; while HCN is expressed in various regions of the basal ganglia, modulating their functions and influencing motor disorders in PD; neuroinflammation triggered by microglial activation represents a shared pathological mechanism in both AD and PD, in which HCN also plays a significant part. This review delves into the neuronal functions governed by HCN, its roles in the aforementioned pathogenesis, its expression patterns in AD and PD, and discusses potential therapeutic drugs targeting HCN for the treatment of these diseases, aiming to offer a novel perspective and inspire future research endeavors.

Silymarin pretreatment protects against ethanol-induced memory impairment: Biochemical and histopathological evidence

BACKGROUND

Ethanol (Eth.) abuse induces memory impairment. Oxidative damage and apoptosis are considered the likely causes of memory impairment. Silymarin (Sil.) is a flavonoid isolated from the plant Silymarin marianum (milk thistle). While studies have reported the neuroprotective effect of Sil. against neurodegenerative processes, the precise mechanism of action of Sil. in Eth.-induced memory impairment remains unclear.

METHODS

Twenty-eight rats were equally divided into four groups: Control (saline 1 ml/rat); Sil. (200 mg/kg for 30 days); Eth. (2 g/kg/day for 30 days); and Sil. + Eth. Behavioral tests including inhibitory avoidance and open field were used to investigate memory and locomotion. Brain antioxidant parameters, including catalase, superoxide dismutase, total antioxidant capacity and total thiol group, plus oxidative parameters, including malondialdehyde and total oxidant status, followed by hippocampal apoptosis (Bax/Bcl2, cleaved caspase) and histopathological changes were evaluated in the groups.

RESULTS

While the administration of Eth. impaired memory, Sil. significantly reversed Eth-induced memory deficits. Eth. administration also augmented brain oxidative and hippocampal apoptosis parameters. In contrast, a marked reduction in brain antioxidant and anti-apoptotic parameters was observed in the Eth. group. At the tissue level, hippocampal sections from Eth.-treated animals revealed severe neuronal damage. The administration of Sil. to Eth.-treated rats remarkably alleviated all the said Eth.-induced biochemical and histopathological effects. On the contrary, Sil. alone did not change the behavior and biochemical/molecular parameters.

CONCLUSION

The memory-enhancing effect of Sil. in Eth.-induced demented rats may be partly mediated by the augmented antioxidant effects and amelioration of apoptotic and histopathological changes.

Promising biomarkers and therapeutic targets for the management of Parkinson's disease: recent advancements and contemporary research

Parkinson's disease (PD) is one of the progressive neurological diseases which affect around 10 million population worldwide. The clinical manifestation of motor symptoms in PD patients appears later when most dopaminergic neurons have degenerated. Thus, for better management of PD, the development of accurate biomarkers for the early prognosis of PD is imperative. The present work will discuss the potential biomarkers from various attributes covering biochemical, microRNA, and neuroimaging aspects (α-synuclein, DJ-1, UCH-L1, β-glucocerebrosidase, BDNF, etc.) for diagnosis, recent development in PD management, and major limitations with current and conventional anti-Parkinson therapy. This manuscript summarizes potential biomarkers and therapeutic targets, based on available preclinical and clinical evidence, for better management of PD.

Silibinin chronic treatment in a rat model of Parkinson disease: A comprehensive in-vivo evaluation and in silico molecular modeling

BACKGROUND

Apoptosis, oxidative stress, and neuroinflammation have been linked to the onset of Parkinson's disease (PD). Although the pre-treatment effects of Silibinin on a PD model have been evaluated, in the current study we investigated the chronic therapeutic effects of Silibinin microinjection on a rat model of established parkinsonism along with behavioral and laboratory markers assessments.

METHOD

Parkinsonism was induced by 6-hydroxydopamine (6-OHDA, 8 μg/2μl/rat). 21 days after that, animals were treated with Silibinin (100, 200, and 300 mg/kg for 15 consecutive days). Every two days, the bar test was used to evaluate Silibinin's anti-cataleptic properties. At the end, myeloperoxidase (MPO) activity and toll-like receptor 4 (TLR4) expression in the substantia nigra pars compacta (SNc), along with cerebrospinal fluid (CSF) levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, IL-6, caspase-3, Bax and Bcl-2 levels were assessed. We used homology modeling to predict the 3D structure of TLR4.

RESULT

Silibinin's Chronic treatment, dose-dependently decreased catalepsy. MPO activity and levels of TNF-α, IL-6, and IL-1β were reduced in Silibinin-treated rats in all three doses. Silibinin decreased Bax/Bcl-2 ratio, caspase-3, and downregulated TLR4 expression. Molecular docking revealed that there were hydrophobic and hydrogen bond interactions between the studied ligand and TLR4. Silibinin formed a stable complex with both monomer and dimer forms of TLR4.

CONCLUSION

In accordance with molecular modeling and alleviation of TLR4 activity with a consequent reduction in oxidative stress, restoration of CSF inflammatory cytokine, and minimization of SNc neuronal apoptosis, long-term therapy with Silibinin offers a potential opportunity for symptomatic PD treatment.

Novel therapeutic interventions for combating Parkinson's disease and prospects of Nose-to-Brain drug delivery

Parkinson disease (PD) is a progressive neurodegenerative disorder prevalent mainly in geriatric population. While, L-DOPA remains one of the major choices for the therapeutic management of PD, various motor and non-motor manifestations complicate the management of PD. In the last two decades, exhaustive research has been carried out to explore novel therapeutic approaches for mitigating motor and non-motor symptoms of PD. These approaches majorly include receptor-based, anti-inflammatory, stem-cell and nucleic acid based. The major limitations of existing therapeutic interventions (of commonly oral route) are low efficacy due to low brain bioavailability and associated side effects. Nanotechnology has been exploited and has gained wide attention in the recent years as an approach for enhancement of bioavailability of various small molecule drugs in the brain. To address the challenges associated with PD therapy, nose-to-brain delivery utilizing nanomedicine-based approaches has been found to be encouraging in published evidence. Therefore, the present work summarises the major challenges and limitations with antiparkinsonian drugs, novel therapeutic interventions, and scope of nanomedicine-based nose-to-brain delivery in addressing the current challenges of antiparkinsonian therapy. The manuscript tries to sensitize the researchers for designing brain-targeted nanomedicine loaded with natural/synthetic scaffolds, biosimilars, and nucleic acids that can bypass the first-pass effect for the effective management of PD.

Compound Dihuang Granule Inhibits Nigrostriatal Pathway Apoptosis in Parkinson's Disease by Suppressing the JNK/AP-1 Pathway

Compound Dihuang Granule (CDG) is widely used in traditional Chinese medicine (TCM) for the treatment of Parkinson's disease (PD). It has been shown to alleviate PD symptoms. However, the molecular mechanisms of its action have not been established. To establish the molecular mechanisms of CDG against PD, we used TCM network pharmacology methods to predict its molecular targets and signaling pathways, followed by experimental validation. The Core Protein protein interaction (PPI) network of the 150 intersections between CDG and PD-related genes, comprising 23 proteins, including CASP3 (caspase-3), MAPK8 (JNK), FOS (c-Fos), and JUN (c-Jun). KEGG and GO analyses revealed that apoptotic regulation and MAPK signaling pathways were significantly enriched. Since c-Jun and c-Fos are AP-1 subunits, an important downstream JNK effector, we investigated if the JNK/AP-1 pathway influences CDG against apoptosis through the nigrostriatal pathways in PD rat models. Molecular docking analysis found that the top three bioactive compounds exhibiting the highest Degree Centrality following online database and LC-MS analysis had high affinities for JNK. Experimental validation analysis showed that CDG decreased the number of rotating laps and suppressed the levels of phosphorylated c-Jun, c-Fos, and JNK, as well as the number of TUNEL positive cells and the cleaved caspase-3 level in the nigrostriatal pathway. Furthermore, CDG treatment elevated the number of TH neurons, TH expression level, and Bcl-2/Bax protein ratio in a 6-OHDA-induced PD rat. These findings are in tandem with those obtained using SP600125, a specific JNK inhibitor. In conclusion, CDG suppresses the apoptosis of the nigrostriatal pathway and relieves PD symptoms by suppressing the JNK/AP-1 signaling pathway.

Antidepressant-Like Effects and Cognitive Enhancement of Coadministration of Chaihu Shugan San and Fluoxetine: Dependent on the BDNF-ERK-CREB Signaling Pathway in the Hippocampus and Frontal Cortex

Background

Fluoxetine (FLU) is the first-line and widely used medication for depression; however, FLU treatment is almost ineffective in 30%-40% of patients with depression. In addition, there are some problems in FLU treatment, such as delayed efficacy, large side effects, and poor tolerance. Chaihu Shugan San (CSS) is a classic and effective antidepressant Chinese herbal medicine that has been used in China for thousands of years. CSS or coadministration of CSS and FLU has become one of the most recommended methods in the treatment of depression in China. However, the specific pathways of CSS and coadministration of CSS and FLU for antidepressant are still unclear.

Objective

This study was designed to evaluate the antidepressant effects of CSS and coadministration of CSS and FLU.

Methods

The chronic unpredictable mild stress (CUMS) rat model was used to simulate depression. 120 healthy adult male Sprague-Dawley (SD) rats were randomly divided into seven groups: the control group, CUMS group, low-dose CSS group, high-dose CSS group, FLU group, coadministration of low-dose CSS and FLU group, and coadministration of high-dose CSS and FLU group. The rats in different groups were given different interventions. Then, the depression-like behavior and cognitive function were evaluated by the sucrose preference test (SPT), forced swimming test (FST), open field test (OFT), and Y-maze test. What is more, the antidepressant mechanism of CSS and coadministration of CSS and FLU were studied through BDNF mRNA, ERK mRNA, CREB mRNA, BDNF, p-ERK/ERK, and p-CREB/CREB levels in the hippocampus and frontal cortex by Western blot and RT-PCR.

Results

Compared with the CUMS group, CSS and coadministration of CSS and FLU could alleviate the depressive symptoms and improve cognitive function in CUMS rats (p < 0.05); CSS and coadministration of CSS and FLU could increase the expression of BDNF, p-CREB/CREB, p-ERK/ERK, and BDNF mRNA, CREB mRNA, and ERK mRNA in the hippocampus and frontal cortex (p < 0.05); CSS and coadministration of CSS and FLU could increase the expression of BDNF, p-CREB/CREB, p-ERK/ERK, and BDNF mRNA, CREB mRNA, and ERK mRNA in the hippocampus and frontal cortex (p < 0.05); CSS and coadministration of CSS and FLU could increase the expression of BDNF, p-CREB/CREB, p-ERK/ERK, and BDNF mRNA, CREB mRNA, and ERK mRNA in the hippocampus and frontal cortex (Discussion and Conclusion. Finally, we found that both CSS and coadministration of CSS and FLU play an antidepressant role, which may be due to the regulation of the BDNF/ERK/CREB signaling pathway in the hippocampus and frontal cortex. Among them, the coadministration of CSS and FLU can enhance the antidepressant effect of CSS or FLU alone, and the underlying mechanism needs further investigation.

Cerebrolysin attenuates ethanol-induced spatial memory impairments through inhibition of hippocampal oxidative stress and apoptotic cell death in rats

The present study investigates the potential neuroprotective effect of cerebrolysin (CBL), a combination of neurotrophic factors, on the cognitive and biochemical alterations induced by chronic ethanol administration in rats. The animals were divided into five groups as follows: control; ethanol (4 g/kg, for 30 days) plus normal saline (Ethanol + NS); ethanol plus CBL 1 mL/kg (Ethanol + CBL 1), ethanol plus CBL 2.5 mL/kg (Ethanol + CBL 2.5); and ethanol plus CBL 5 mL/kg (Ethanol + CBL 5). The Morris water maze (MWM) test was performed to assess cognitive impairment. The status of the lipid peroxidation marker MDA, antioxidant capacity, as well as alterations of the apoptotic factors such as Bcl-2, BAX, and cleaved caspase-9 and -3, were evaluated in the hippocampus. The results showed that CBL treatment not only normalized the increased MDA levels in the alcoholic rats and enhanced antioxidant defense, but also reduced the Bax/Bcl-2 ratio and cleaved caspase-9 and -3 in the hippocampus. These results were parallel with improvement in spatial memory performance in the MWM test. The findings of the present study provide evidence for the promising therapeutic effect of CBL in chronic ethanol consumption through counteracting oxidative stress and apoptosis markers.

Sleep deprivation disrupts striatal anti-apoptotic responses in 6-hydroxy dopamine-lesioned parkinsonian rats

Objective(s):

The present study was conducted to examine the effect of sleep deprivation (SD) on the anti-apoptotic pathways in Parkinsonian rats.

Materials and Methods:

Male Wistar rats (n = 40) were assigned to four groups (10 animals each): sham surgery (Sham), 6-hydroxydopamine (6-OHDA)-lesioned (OH), 6-OHDA-lesioned plus grid control (OH+GC), 6-OHDA-lesioned plus SD (OH+SD). Parkinson’s disease (PD) model was induced by the unilateral intra-striatal infusion of 6-OHDA (10 µg/rat). SD (4 hr/day, for 14 days) was induced using a multiple platforms water tank. On the last day of interventions, animals were subjected to open field test for horizontal motor performance assessment. Also, brain-derived neurotrophic factor (BDNF), Bcl-2 and Bax were assessed in the striatum of study groups.

Results:

SD obscured the motor deficits of PD animals observed in open field test. BDNF level and Bcl2/Bax ratio significantly increased in the OH group, and SD reduced their levels in the PD animals.

Conclusion:

SD suppressed the anti-apoptotic compensatory responses in the striatum; therefore, it may accelerate continual neuronal cell death in PD.

Silymarin prevents apoptosis through inhibiting the Bax/caspase-3 expression and suppresses toll like receptor-4 pathway in the SNc of 6-OHDA intoxicated rats

BACKGROUND AND PURPOSE

Several lines of evidence show that apoptosis, oxidative stress and neuroinflammation are associated with the development of Parkinson's disease (PD). In the present study, we investigated the effect of pre-treatment with silymarin (SM) on oxidative stress, apoptosis and toll-like receptor 4 (TLR4) expression in substantia nigra pars copmacta (SNc) of 6-hydroxydopamine (6-OHDA)-lesioned rats.

METHODS

Animals were pretreated with 100, 200 or 300 mg/kg of SM daily for 5 days and at 6th day 6-OHDA (8 μg/2 μl) was infused unilaterally into the central region of the SNc.

RESULTS

6-OHDA decreased the total glutathione and antioxidant enzymes activity in the SNc. Interestingly, we found that 6-OHDA caused to TLR4 up regulation. The SNc levels of glutathione, superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase were significantly higher in the SM pretreated rats. SM strongly decreased 6-OHDA-induced elevation of SNc apoptosis, caspase-3 and Bax/Bcl-2 ratio. Furthermore, SM markedly (p < 0.001) prevented from SNc over expression of TLR4 caused by 6-OHDA. A significantly high positive correlation was seen between TLR4 activity with caspase-3 protein levels (r = 0.896, P < 0.01), Bax protein levels (r = 0.96, P < 0.01).

CONCLUSION

Pre-treatment of 6-OHDA-lesioned rats with SM reduces SNc neuronal apoptosis possibly through inhibition of TLR4 over expression. Further clinical study should be carried out to prove potential application of SM for protection against PD in susceptible individuals.

A Comparative study for striatal-direct and -indirect pathway neurons to DA depletion-induced lesion in a PD rat model

Striatal-direct and -indirect Pathway Neurons showed different vulnerability in basal ganglia disorders. Therefore, present study aimed to examine and compare characteristic changes of densities, protein and mRNA levels of soma, dendrites, and spines between striatal-direct and -indirect pathway neurons after DA depletion by using immunohistochemistry, Western blotting, real-time PCR and immunoelectron microscopy techniques. Experimental results showed that: 1) 6OHDA-induced DA depletion decreased the soma density of striatal-direct pathway neurons (SP+), but no significant changes for striatal-indirect pathway neurons (ENK+). 2) DA depletion resulted in a decline of dendrite density for both striatal-direct (D1+) and -indirect (D2+) pathway neurons, and D2+ dendritic density declined more obviously. At the ultrastructure level, the densities of D1+ and D2+ dendritic spines reduced in the 6OHDA groups compared with their control groups, but the density of D2+ dendritic spines reduced more significant than that of D1. 3) Striatal DA depletion down-regulated protein and mRNA expression levels of SP and D1, on the contrary, ENK and D2 protein and mRNA levels of indirect pathway neurons were up-regulated significantly. Present results suggested that indirect pathway neurons be more sensitive to 6OHDA-induced DA depletion.

Gastrodin microinjection suppresses 6-OHDA-induced motor impairments in parkinsonian rats: insights into oxidative balance and microglial activation in SNc

PURPOSE OF THE RESEARCH

In this study, we appraised the effect of pre-treatment with intra-cerebro ventricular (i.c.v) microinjection of gastrodin (Gst) on catalepsy, motor imbalance, substantia nigra pars compacta (SNc) myeloperoxidase (MPO) activity, lipid peroxidation levels, nitric oxide (NO) production and total antioxidant capacity (TAC) in 6-hydroxydopamine (6-OHDA) rats model of PD.

MATERIALS AND METHODS

Male Wistar rats were pre-treated with i.c.v microinjections of Gst (20, 40 and 80 μg/3 μl/rat) for five consecutive days. Then, catalepsy and motor balance were induced by unilateral infusion of 6-OHDA (8 μg/2 μl/rat) into the SNc. The anti-cataleptic and motor balance improving effect of Gst was assessed by the Bar test and Rotarod 3 weeks after neurotoxin injection, respectively. SNc MPO activity and lipid peroxidation levels, NO production and TAC were assessed at the end of behavioral experiments.

RESULTS

Our data demonstrated that Gst pre-treatment significantly (p < 0.001) was prevented motor in-coordination and catalepsy in neurotoxin lesioned rats. The most motor improving effect was seen at 80 μg Gst (p < 0.001). Pre-treatment of parkinsonian rats with Gst meaningfully (p < 0.001) was suppressed MPO activity, lipid peroxidation and NO production. Furthermore, the TAC level in the SNc was increased (p < 0.001) in Gst-microinjected rats about to the normal non-parkinsonian animals.

MAJOR CONCLUSIONS

In summary, pre-treatment with Gst abolished 6-OHDA-induced catalepsy and improved motor incoordination by decreasing: SNc MPO activity, lipid peroxidation levels and NO production, and restoring SNc levels of TAC to the levels of healthy rats.

Ginsenoside Rg3 Suppresses Proliferation and Induces Apoptosis in Human Osteosarcoma

Osteosarcoma is the most common primary malignancy of bone in children and the elderly. Recently, more and more researches have demonstrated that Ginsenoside Rg3 (Rg3) is involved in chemotherapy resistance in many cancer, making it a promising Chinese herbal monomer for oncotherapy. In this study, we investigated the efficacy of Rg3 in human osteosarcoma cell lines (MG-63, U-2OS, and SaOS-2). Cell proliferation was measured by CCK8 assay. The migration of cells was examined using the scratch assay method. Quantification of apoptosis was assessed further by flow cytometry. In addition, the expression of apoptosis-related genes (caspase9, caspase3, Bcl2, and Bax) were investigated using RT-PCR. We further investigated the protein level expression of Bcl 2, cleaved-caspase3, and PI3K/AKT/mTOR signaling pathway factors by Western blot assay. Our results revealed that Rg3 inhibited the proliferation and migration of human osteosarcoma cells and induced apoptosis in a concentration- and time-dependent manner. Western blot results showed that Rg3 reduced the protein expression of Bcl2 and PI3K/AKT/mTORbut increased the levels of cleaved-caspase3. Therefore, we hypothesized Rg3 inhibits the proliferation of osteosarcoma cell line and induces their apoptosis by affecting apoptosis-related genes (Bcl2, caspase3) as well as the PI3K/AKT/mTOR signaling pathway. To conclude, Rg3 is a new therapeutic agent against osteosarcoma.