Dual ameliorative effects of Ningdong granule on dopamine in rat models of Tourette's syndrome

Mechanistic insights and therapeutic approaches in tic disorders: The distinctive role of ethnomedicine and modern medical interventions

Tic disorders (TDs) are a class of neurodevelopmental disorders that have received considerable scientific attention. The genesis of TDs is increasingly understood as a complex interplay of neurobiological, genetic, and immunological factors. Animal model studies have elucidated the pathophysiology of TDs, paving the way for innovative therapeutic approaches. This review provides a comprehensive analysis of the etiologic basis, experimental framework, and treatment strategies for TDs, highlighting the contributions of ethnomedicine and modern medicine. Our synthesis aims to deepen the understanding of the disease and spur the development of superior treatments. In addition, we present new insights and hypotheses for the future management of TDs, emphasizing the need for continued research into their etiology and progression, as well as the pursuit of more effective therapies. We advocate personalized, holistic care strategies that focus on symptom relief and improving patients' quality of life. Overall, this review provides a critical compendium for TD researchers and practitioners to help navigate the complexities of these disorders.

Exogenous GABA Alleviates Tourette Syndrome-Like Behavior in Sprague-Dawley Rats by Altering Gut Microbiota and Striatum Metabolism

Context

Tourette syndrome (TS) is a common chronic neuropsychiatric disorder with a prevalence of approximately 1% in children and adolescents. TS is characterized by sudden involuntary motor tics along with vocal tics. A pathological study on postmortem patients has reported a 50-60% reduction in striatal gamma-aminobutyric acidergic (GABAergic) interneurons, suggesting a role for GABAergic system imbalances in tic disorder development. However, the effect of exogenous GABA administration on tic alleviation remains unreported.

Objective

In this study, we aim to investigate the therapeutic effects of exogenous GABA on TS-like behaviors in Sprague-Dawley rats and explore its potential mechanisms, including gut microbiota regulation, oxidative stress mitigation, and restoration of GABA-glutamate balance, to provide insights into TS pathogenesis and alternative treatment strategies.

Materials and Methods

A TS model rat was established through intraperitoneal administration of 3,3-Iminodipropionitrile (150 mg/kg/day), followed by GABA (20 mg/kg/day) administration by gavage. 15 minutes of behavioral testing (stereotypical behavior and head twitching behavior) was then conducted. 16S rRNA sequencing identified microbiome changes, and LC-MS assessed striatal metabolite changes.

Results

The results showed that a 4-week GABA treatment alleviated TS-like behavior in rats. GABA treatment led to an increase in Acinetobacter and other beneficial bacteria. GABA also significantly upregulated 15 striatal metabolites compared with TS group. By correlation analysis of striatal metabolites and intestinal bacteria, statistical analysis showed that Clostridium_sensu_stricto_1 was negatively correlated with metabolites on the top 20 differential gut microbiota and metabolites. Moreover, changes in gut microbiota correlated with alterations in striatal metabolites, suggesting a gut-brain axis involvement.

Conclusion

Exogenous GABA alleviated TS-like behavior in rats by reducing harmful gut flora and modulating striatal GABA-glutamate metabolism. Despite challenges like low blood-brain barrier permeability and dose safety in humans, GABA's therapeutic potential may be realized through prodrug development and optimized dosing. These findings are preliminary and require further clinical validation.

Network Pharmacology Combined with Animal Models to Investigate the Mechanism of ChangPu YuJin Tang in the Treatment of Tourette Syndrome

BACKGROUND

ChangPu YuJin Tang (CPYJT) is a Chinese herbal formula that has been shown to be an effective therapeutic strategy for pediatric patients with Tourette Syndrome (TS). Using an integrated strategy of network pharmacology and animal model, the aim of this study was to investigate the mechanism of CPYJT in the treatment of TS.

METHODS

Compound libraries of CPYJT were established using databases, such as the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). The TCMSP database and Swiss Target Prediction database were used to predict the targets. The above results were constructed into a CPYJT-Drug-Component-Target network. Moreover, TS targets were predicted using GeneCards and other databases. The targets corresponding to the potential ingredients in CPYJT and the targets corresponding to TS were taken as the intersections to construct the CPYJT-TS network. The target network was analysed by PPI using the string database. GO and KEGG enrichment analyses were performed on the target network. The whole process was performed using Cytoscape 3.7.2 to make visual network diagrams of the results. CPYJT was characterised by Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry (UHPLC-MS). Transmission Electron Microscopy (TEM) was used to observe the structural changes of CPYJT on the neuronal cells of the IDPN model rats. RT-PCR and Western Blot were used to analyse the changes in the mRNA and protein expression levels of BDNF, TrkB, PI3K, and AKT in the cortex, striatum, and thalamus brain regions after CPYJT administration in IDPN model rats.

RESULTS

Network pharmacology and UHPLC-MS studies revealed that CPYJT acted on the TS through multiple neurotransmitters and the BDNF/TrkB and PI3K/AKT signalling pathways. CPYJT ameliorated neurocellular structural damage in the cortex, striatum, and thalamus of TS model rats. Additionally, CPYJT up-regulated the levels of BDNF, TrkB, PI3k, and AKT in the cortex, striatum, and thalamus of TS model rats.

CONCLUSION

It was found that CPYJT protected neuronal cells from structural damage in multiple brain regions and affected the expression levels of BDNF, TrkB, PI3K, and Akt in the cortex, striatum, and thalamus during TS treatment.

Clinical management of children with tic disorder: insights from therapeutic visits in China-a real-world study

Objective

This retrospective study aims to investigate the treatment of tic disorder (TD) in Dongfang Hospital affiliated with Beijing University of Chinese Medicine, explore its underlying mechanism, and provide valuable insights for future research and clinical management of TD.

Methods

The electronic medical records of children with TD, from 2015 to 2021, were extracted from the information system of Dongfang Hospital affiliated with Beijing University of Chinese Medicine. The clinical characteristics of TD, utilization patterns of Chinese herbal medicine and synthetic drugs in prescriptions, as well as their pharmacological effects, were statistically described and categorized. In addition, association rules and network pharmacology were employed to identify core prescriptions (CPs) and elucidate their microscopic molecular mechanisms in treating TD.

Results

The age range of the children was from 6 to 11 years, with a higher proportion of male participants than female ones. The average duration of treatment was 6 weeks. Regimen Z for the treatment of TD can be summarized as follows: Chinese herbal medicine [Saposhnikoviae Radix (FangFeng), Puerariae Lobatae Radix (GeGen), Uncariae Ramulus cum Uncis (GouTeng), Acori Tatarinowii Rhizoma (ShiChangPu), Chuanxiong Rhizoma (ChuanXiong)] and vitamins [lysine, inosite, and vitamin B12 oral solution] form the basic treatment, combined with immunomodulators, antibiotics, electrolyte-balancing agents, and antiallergic agents. CPs primarily exerted their effects through the modulation of gene expression (transcription), the immune system, and signal transduction pathways, with interleukin-4 and interleukin-13 pathways being particularly crucial. Among the lysine synthetic drugs used, inosite and vitamin B12 oral solution were the most frequently prescribed.

Conclusion

The regimen Z drug treatment holds significant importance in the field, as it exerts its therapeutic effects through a multitude of pathways and intricate interventions. Chinese herbal medicine primarily regulates immune system-related pathways, while synthetic drugs predominantly consist of vitamins.

Effects of Chemogenetic Inhibition of D1 or D2 Receptor-Containing Neurons of the Substantia Nigra and Striatum in Mice With Tourette Syndrome

As tourette syndrome (TS) is a common neurobehavioral disorder, the primary symptoms of which include behavioral stereotypies. Dysfunction of the substantia nigra-striatum network could be the main pathogenesis of TS, which is closely associated with dopamine (DA) and its receptors. TS is often resistant to conventional treatments. Therefore, it is necessary to investigate the neurobiological mechanisms underlying its pathogenesis. In this study, we investigated whether chemogenetic activation or inhibition of dopaminergic D1 receptor (D1R)- or D2 receptor (D2R)-containing neurons in the substantia nigra pars compacta (SNpc) or dorsal striatum (dSTR) affected the stereotyped behavior and motor functions of TS mice. Intraperitoneal injection of 3,3'-iminodipropionitrile (IDPN) was used to induce TS in mice. Stereotyped behavior test and open-field, rotarod, and grip strength tests were performed to evaluate stereotyped behavior and motor functions, respectively. Immunofluorescence labeling was used to detect the co-labeling of virus fluorescence and D1R or D2R. We found that chemogenetic inhibition of D1R- or D2R-containing neurons in the SNpc and dSTR alleviated behavioral stereotypies and motor functions in TS mice. Chemogenetic activation of D1R-containing neurons in the dSTR aggravated behavioral stereotypies and motor functions in vehicle-treated mice, but neither was aggravated in TS mice. In conclusion, chemogenetic inhibition of D1R- or D2R-containing neurons in the SNpc and dSTR alleviated behavioral stereotypies of TS, providing a new treatment target for TS. Moreover, the activation of D1R-containing neurons in the dSTR may contribute to the pathogenesis of TS, which can be chosen as a more precise target for treatment.

Immune function changes of the IDPN-induced Tourette syndrome rat model

There may be immunologic alternations during Tourette syndrome (TS) development. This study aimed to determine the immune function changes in different aspects (spleen or thymus index, plasma cytokines, and T cell) in an 3,3'-iminodipropionitrile (IDPN)-induced rat model of TS. Male Sprague-Dawley rats were assigned to control and TS groups. The control group received intraperitoneal infections of normal saline (5 ml kg^-1  day^-1 ), and the TS rats were injected with IDPN (150 mg kg^-1  day^-1 ). The spleen and thymus indices were calculated. The expression of anti-inflammatory cytokines and inflammatory cytokines TNF-α, in peripheral blood were measured by ELISA and Western blotting. The proportion of CD3+, CD4+, CD8+, Treg, Th1, and Th2 cells were determined by fluorescence-activated cell sorting analysis. After 1 week of IDPN treatment, TS rats had decreased spleen and thymus weights versus control. The plasma levels of IL-4, IL-10, IL-12, IFN-γ, and TNF-α were significantly increased, while no significant difference in TGF-β was found. Flow cytometry analysis demonstrated that TS rats had significantly reduced CD3+ and CD4+ cells in spleen, without any change in the proportion of CD8+ cells. Furthermore, the ratio of Treg cells (CD4+/CD25+/FoxP3+) was decreased in TS rats; simultaneously, Th1 cells (CD4+/IFN-γ+) and Th2 cells (CD4+/IL4+) were dramatically increased. Together, IDPN can trigger immune dysfunction through impairment of matured Th cells, in particular for the Treg subset.

Ningdong Granule Upregulates the Striatal DA Transporter and Attenuates Stereotyped Behavior of Tourette Syndrome in Rats

This study aimed to evaluate the possible mechanism of Ningdong granule (NDG) for the treatment of Tourette syndrome (TS). The rats with stereotyped behavior were established by microinjection with TS patients' sera; then, the model rats were divided into NDG and haloperidol (Hal) group, and the nonmedication model rats were regarded as treatment control (TS group). The stereotyped behavior of the rats was recorded, the level of dopamine (DA) in striatum, and the content of homovanillic acid (HVA) in sera were tested, and dopamine transporter (DAT) expression was measured in the study. The experimental results showed that NDG effectively inhibited the stereotyped behavior (P < 0.01), decreased the levels of DA in the striatum (P < 0.05), increased the content of sera HVA (P < 0.01), and enhanced the protein and mRNA expression of DAT in the striatum (P < 0.01). Additionally, the results also revealed Hal could improve the stereotyped behavior as well but had no remarkable influence on DAT expression and DA metabolism. In conclusion, NDG attenuates stereotyped behavior, and its mechanism of action might be associated with the upregulation of DAT expression to regulate DA metabolism in the brain.

Effects of Jian-Pi-Zhi-Dong Decoction on the Expression of 5-HT and Its Receptor in a Rat Model of Tourette Syndrome and Comorbid Anxiety

BACKGROUND Anxiety is one of the common comorbidities of Tourette syndrome (TS). The serotonin (5-HT) system is involved in both TS and anxiety. Jian-pi-zhi-dong decoction (JPZDD) is widely used. However, the mechanism remains unknown. In this study, a rat model of TS and comorbid anxiety was used to evaluate the effect of JPZDD on 5-HT and its receptor. MATERIAL AND METHODS 48 rats were divided into 4 groups randomly (n=12). The model was established by empty water bottle stimulation plus iminodipropionitrile injection for 3 weeks. Then the control and model groups were gavaged with saline, while the treatment groups were gavaged with fluoxetine hydrochloride (Flx) or JPZDD. Body weights were measured, and behavioral tests were evaluated with stereotypy and elevated plus maze. The morphologic characters were observed by hematoxylin and eosin staining. The content of 5-HT was detected by enzyme-linked immunosorbent assay and high-performance liquid chromatography. The expression of 5-HT2C receptor was detected by western blot and quantitative polymerase chain reaction. RESULTS The stereotypy score was lower and the time spent in the open arm was longer in the JPZDD group compared with the model group. After the treatment of Flx or JPZDD, the structure of neurons became gradually normal and the cells were arranged neatly. The contents of 5-HT in the treatment groups were higher compared with the model group in the striatum. The expression of 5-HT2C mRNA in the striatum of JPZDD and Flx groups decreased compared with the model group, and the JPZDD group was lower than the Flx group. CONCLUSIONS JPZDD alleviated both tic and anxiety symptoms and the mechanism may be via reducing the expression of 5-HT2C mRNA in the striatum, increasing the concentration of 5-HT, and enhancing the activity of the 5-HT system, which in turn exerts neuro-inhibition.

Effects of Acupuncture on Behavioral Stereotypies and Brain Dopamine System in Mice as a Model of Tourette Syndrome

Tourette syndrome (TS), a developmental neurobehavioral disorder, is characterized by involuntary behavioral stereotypies. Clinical studies have confirmed the positive effect of acupuncture on treating TS, but the underlying mechanisms are not fully understood. In the present study, we used behavioral tests, Western blotting, double-immunofluorescence labeling, and fluorescence spectrophotometry to investigate whether acupuncture performed at acupoints "Baihui" (GV20) and "Yintang" (GV29) affected behavioral stereotypies and regulated the dopamine (DA) system in three different brain regions in Balb/c mice injected with 3,3'-iminodipropionitrile (IDPN) as a model for TS. We found that acupuncture alleviated behavioral stereotypies, down-regulated the expression of D1R and D2R in the striatum (STR) and substantia nigra pars compacta (SNpc), and decreased the concentration of DA in the STR, SNpc, and prefrontal cortex (PFC) as well. Moreover, acupuncture reduced the expression of tyrosine hydroxylase (TH) in the SNpc. Conclusively, acupuncture ameliorated behavioral stereotypies by regulating the DA system in the STR, SNpc, and PFC. Our findings provide novel evidence for the therapeutic effect of acupuncture on TS.

A Chinese Herbal Formulation, Xiao-Er-An-Shen Decoction, Attenuates Tourette Syndrome, Possibly by Reversing Abnormal Changes in Neurotransmitter Levels and Enhancing Antioxidant Status in Mouse Brain

Xiao-Er-An-Shen Decoction (XEASD) has been used clinically for the treatment of Tourette syndrome (TS) in children for more than 20 years in mainland China. The biochemical mechanism underlying the therapeutic action produced by XEASD treatment against TS remains unknown. However, a previous study has shown that pre-incubation of PC12 neuronal cells with XEASD can induce neurite outgrowth and protect against oxidative stress. In the present study, using a mouse model of TS induced by 3,3’-iminodipropionitrile (IDPN), stereotypy scoring, and locomotor activity were assessed. Levels of neurotransmitters including glutamate, aspartate, and gamma-aminobutyric acid (GABA) in brain tissue as well as plasma cyclic adenosine monophosphate (cAMP) were measured using assay kits. The ratio of reduced glutathione (GSH)/oxidized glutathione (GSSG) and Mn-superoxide dismutase (MnSOD) activity in brain mitochondrial fractions as well as mitochondrial glutathione reductase and cytosolic γ-glutamylcysteine activities were also examined. The phosphorylation of cAMP-responsive element binding protein (CREB) in brain tissue was measured by Western blot analysis. XEASD treatment was found to significantly ameliorate the severity of behavioral symptoms in affected mice, as evidenced by decreases in the stereotypy score and locomotor activity. The beneficial effect of XEASD was accompanied by the reversal of abnormal levels of GABA, glutamate, and aspartate, in brain tissue of IDPN-challenged mice. In addition, XEASD treatment increased plasma cyclic adenosine monophosphate (cAMP) levels and activated the phosphorylation of CREB in brain tissue of TS mice. Furthermore, XEASD treatment was found to enhance the antioxidant status of brain tissue in affected mice, as evidenced by increases in the GSH/GSSG ratio and the activity of MnSOD in brain mitochondrial fractions. Taken together, these experimental results will hopefully provide insight into the pharmacological basis for the beneficial effects of XEASD in children suffering from TS.

Regulatory effects of Ningdong granule on dopaminergic and serotonergic neurotransmission in a rat model of Tourette syndrome assessed by PET

Dysfunctions in dopamine (DA) and serotonin (5‑HT) metabolism have been widely implicated in Tourette syndrome (TS); however, the exact nature of these dysfunctions remains unclear. The objective of the present study was to investigate the variation in DA and 5‑HT metabolism in a rat model of TS, and to evaluate the therapeutic effect of Ningdong granule (NDG), a traditional Chinese medicine (TCM) preparation used specifically for the treatment of TS. Rats were treated with 3,3'‑iminodipropionitrile for 7 days to induce the model of TS, and were then intragastrically administered NDG each day. After 8 weeks of treatment, micro‑positron emission tomography was used to measure the binding of DA D2 receptors (D2Rs), DA transporters (DATs), 5‑HT2A receptors (5‑HT2ARs) and 5‑HT transporters (SERTs) in brain regions of interest. The results indicated that NDG could significantly reduce the typical characteristics of TS in the rat model. Decreased D2R binding and increased DAT binding were detected in the striatum compared with the binding activities in untreated rats. The density of 5‑HT2AR was also significantly increased in the striatum following NDG treatment; however, SERT levels were decreased in certain brain regions, including the striatum, cortex, nucleus accumbens and amygdala. Taken together, the current results demonstrated that NDG may be effective in treating patients with TS.

Current Approaches and New Developments in the Pharmacological Management of Tourette Syndrome

Tourette syndrome (TS) is a neurodevelopmental disorder of unknown etiology characterized by spontaneous, involuntary movements and vocalizations called tics. Once thought to be rare, TS affects 0.3-1% of the population. Tics can cause physical discomfort, emotional distress, social difficulties, and can interfere with education and desired activities. The pharmacologic treatment of TS is particularly challenging, as currently the genetics, neurophysiology, and neuropathology of this disorder are still largely unknown. However, clinical experience gained from treating TS has helped us better understand its pathogenesis and, as a result, derive treatment options. The strongest data exist for the antipsychotic agents, both typical and atypical, although their use is often limited in children and adolescents due to their side-effect profiles. There are agents in a variety of other pharmacologic categories that have evidence for the treatment of TS and whose side-effect profiles are more tolerable than the antipsychotics; these include clonidine, guanfacine, baclofen, topiramate, botulinum toxin A, tetrabenazine, and deutetrabenazine. A number of new agents are being developed and tested as potential treatments for TS. These include valbenazine, delta-9-tetrahydrocannabidiol, and ecopipam. Additionally, there are agents with insufficient data for efficacy, as well as agents that have been shown to be ineffective. Those without sufficient data for efficacy include clonazepam, ningdong granule, 5-ling granule, omega-3 fatty acids, and n-acetylcysteine. The agents that have been shown to be ineffective include pramipexole and metoclopramide. We will review all of the established pharmacologic treatments, and discuss those presently in development.

Dual regulating effect of Ningdong granule on extracellular dopamine content of two kinds of Tourette's syndrome rat models

Tourette's syndrome (TS) is an inherited chronic neuropsychiatric disorder characterized by involuntary stereotyped motor and phonic behaviors called tics. Its pathogenesis is still unclear and its treatment remains limited. Our previous basic and clinical studies have shown that traditional Chinese medicine (TCM) preparation Ningdong granule (NDG) is effective for the treatment of TS with little side effects. In the current study, two TS rat models (Apomorphine (Apo)- and 3,3'-iminodipropionitrile (IDPN)-induced) were used to explore the dual regulating effects and mechanisms of NDG on extracellular DA concentration. We found that NDG could regulate the extracellular DA concentration dually: it could make a gradual recovery in extracellular DA content from both an up-regulated level in Apo-induced rats and down-regulated level in IDPN-induced rats measured by high-performance liquid chromatography (HPLC). The protein expression of DA transporter (DAT) was measured by Western blot and the result showed that NDG could elevate DAT expression when DA release was up-regulated and could decrease DAT expression when extracellular DA concentration was down-regulated. The main mechanism of the dual regulating effect of NDG on extracellular DA release might be related to DAT protein expression in TS, through which the released DA is re-uptaken into nerve terminals. Taken together, compared with conventional single-target anti-tics drugs such as haloperidol (Hal), NDG with the dual regulating effect would be more significant for TS treatment.