Pentoxifylline attenuates iminodipropionitrile-induced behavioral abnormalities in rats

Volatile oil from Acori graminei Rhizoma affected the synaptic plasticity of rats with tic disorders by modulating dopaminergic and glutamatergic systems

ETHNOPHARMACOLOGICAL RELEVANCE

Acori graminei Rhizoma is a commonly used traditional Chinese medicine for treating TD, with its main component being calamus volatile oil. Volatile Oil from Acori graminei Rhizoma (VOA)can protect nerve cells and alleviate learning and memory disorders. However, the mechanism of anti-tic of VOA is still unclear.

AIM OF THE STUDY

We aimed to explore the effects of Volatile Oil from Acori Tatarinowii Rhizoma (VOA) on striatal dopaminergic and glutamatergic systems and synaptic plasticity of rats with Tic Disorder (TD), as well as its pharmaceutical mechanism against TD.

MATERIALS AND METHODS

This study involved 48 (three-week-old) Sprague Dawley (SD) rats, which were randomly divided into two primary groups: Control (8) and TD (40). Rats in the TD group were injected intraperitoneally with 3,3-iminodipropionitrile (IDPN) to construct the TD rat model. They were divided into five subgroups: Model, Tiapride, VOA-high, VOA-medium, and VOA-low (N = 8). After modeling, VOA was administrated to rats in the VOA groups through gavage (once/day for four consecutive weeks), while rats in the blank control and model groups received normal saline of the same volume. The animals' behavioral changes were reflected using the stereotypic and motor behavior scores. After interferences, patterns of striatal neurons and the density of dendritic spines were investigated using H&E and Golgi staining, and the ultrastructure of striatal synapses was examined using Transmission Electron Microscopy (TEM). Furthermore, Ca2+ content was determined using the Ca2+ detector, and Dopamine (DA) and Glutamate (GLU) contents in serum and striatum were detected through ELISA. Finally, DRD1, DRD2, AMPAR1, NMPAR1, DAT, VMAT2, CAMKⅡ, and CREB expression in the striatum was detected using Quantitative real-time PCR (qRT-PCR), Western Blotting (WB) and Immunohistochemical (IHC) methods.

RESULTS

Compared to rats in the blank control and model groups, rats in the VOA groups showed lower stereotypic behavior scores. Furthermore, rats in the VOA groups exhibited relieved, neuron damage and increased quantities of neuronal dendrites and dendritic spines Additionally, based on TEM images show that, the VOA groups showed a clear synaptic structure and increased amounts of postsynaptic dense substances and synaptic vesicles. The VOA groups also exhibited reduced Ca2+ contents, and upregulation of DRD1, DRD2, DAT, AMPAR1, and NMPAR1 and downregulation of VMAT-2, CAMKⅡ, and CREB in the striatum.

CONCLUSIONS

In summary, VOA could influence synaptic plasticity by tuning the dopaminergic and glutamatergic systems, thus relieving TD.

Vitamin D3 improves iminodipropionitrile-induced tic-like behavior in rats through regulation of GDNF/c-Ret signaling activity

Children with chronic tic disorders (CTD), including Tourette syndrome (TS), have significantly reduced serum 25-hydroxyvitamin D [25(OH)D]. While vitamin D3 supplementation (VDS) may reduce tic symptoms in these children, its mechanism is unclear. The study aim was to investigate the effects and mechanisms of vitamin D deficiency (VDD) and VDS on TS model behavior. Forty 5-week-old male Sprague-Dawley rats were randomly divided into (n = 10 each): control, TS model, TS model with VDD (TS + VDD), or TS model with VDS (TS + VDS; two intramuscular injections of 20,000 IU/200 g) groups. The VDD model was diet-induced (0 IU vitamin D/kg); the TS model was iminodipropionitrile (IDPN)-induced. All groups were tested for behavior, serum and striatal 25(OH)D and dopamine (DA), mRNA expressions of vitamin D receptor (VDR), glial cell line-derived neurotrophic factor (GDNF), protooncogene tyrosine-protein kinase receptor Ret (c-Ret), and DA D1 (DRD1) and D2 (DRD2) receptor genes in the striatum. TS + VDD had higher behavior activity scores throughout, and higher total behavior score at day 21 compared with TS model. In contrast, day 21 TS + VDS stereotyped behavior scores and total scores were lower than TS model. The serum 25(OH)D in TS + VDD was < 20 ng/mL, and lower than control. Striatal DA of TS was lower than control. Compared with TS model, striatal DA of TS + VDD was lower, while in TS + VDS it was higher than TS model. Furthermore, mRNA expression of VDR, GDNF, and c-Ret genes decreased in TS model, and GDNF expression decreased more in TS + VDD, while TS + VDS had higher GDNF and c-Ret expressions. VDD aggravates, and VDS ameliorates tic-like behavior in an IDPN-induced model. VDS may upregulate GDNF/c-Ret signaling activity through VDR, reversing the striatal DA decrease and alleviating tic-like behavior.

Integrated network pharmacology and experimental verification to explore the molecular mechanism of Jingxin Zhidong formula for treating Tic disorder

ETHNOPHARMACOLOGICAL RELEVANCE

As a traditional Chinese medicine formula, Jingxin Zhidong Formula (JXZDF) based on ancient amber powder has been prescribed to alleviate tic disorders (TD) according to our clinical practice for many years. However, the underlying molecular mechanisms remain largely unknown.

AIM OF STUDY

To explore the potential mechanism of JXZDF in the treatment of TD by using network pharmacology and experimental validation.

MATERIALS AND METHODS

The chemical components of JXZDF were detected and the potential pathway enrichment analyses were conducted based on network pharmacology. Finally, we performed cell viability assays and Western blotting on LPS-induced BV-2 cells, and subsequently performed behavioral tests and Western blotting in SD rats model for TD to explore the mechanism of JXZDF on TD.

RESULTS

By LC-ESI-MS/MS system and searching the databases, we identified 5 key compounds and 29 hub targets of JXZDF on TD. KEGG enrichment analysis showed that PI3K/AKT signaling pathway may be the key pathway for JXZDF on TD. The vitro experimental results proved that JXZDF can inhibit the phosphorylation of PI3K and AKT proteins on LPS-induced BV-2 cells. The animal experimental results indicated that JXZDF can effectively alleviate the stereotypic behavior and hyperactivity of the TD rats, and downregulated PI3K/AKT pathway to inhibit microglia activation in the hippocampus tissue.

CONCLUSION

This study indicated that JXZDF can change microglial activation and expression of proinflammatory mediators through the inactivation of PI3K/AKT signaling pathway, which may be one of the mechanisms of JXZDF in treating TD.

The effects of music therapy on amino acid neurotransmitters: Insights from an animal study

BACKGROUND

This study aimed to explore the neurobiological effects of "Chinese Traditional Five-Elements Music Therapy" on rats and to determine its effects on amino acid neurotransmitter levels, the excitatory/inhibitory(E/I) balance and the Glu-Gln cycle.

METHODS

Male Wistar rats were assigned at random to the experimental groups (Gong/powerful; Shang/sad; Jue/gentle; Zhi/joyful; Yu/serene music group) and the control group(n=8/group).The experimental groups were exposed daily to music(2 hours per day; mild sound pressure levels, between 50 and 60 dB) for 28 consecutive days. Finally, we hypothesized concentrations of Glu and GABA to match the music types and measured additionally Asp, Gly, Gln, and Glu/GABA ratio in striatum by UPLC-3QMS.

RESULT

Effects in the predicted direction were observed for Gong (Glu +, GABA -); Shang (Glu -; GABA +); Jue (Glu 0; GABA 0); and Zhi (Glu +; GABA -); but not Yu music (Glu + contrary to hypothesis; GABA + as hypothesized)." In addition, significant difference in Gln levels were also present in the zhi, Gong and Yu music groups compared to the controls.

CONCLUSION

Our study showed that different melodic music produced different effects on amino acid neurotransmitter levels. "Chinese Traditional Five-Elements Music Therapy" affected the amino acid neurotransmitter levels, the E/I balance and the Glu-Gln cycle in the striatum of rats, which may reflect altered glutamatergic and GABAergic system.

Time-Course Evaluation of Iminodipropionitrile-Induced Liver and Kidney Toxicities in Rats: A Biochemical, Molecular and Histopathological Study

Iminodipropionitrile (IDPN) is known to produce axonopathy and vestibular hair cell degeneration. Recent histopathological studies have shown IDPN-induced liver and kidney toxicities in rodents; however, the associated mechanisms are not clearly understood. We investigated the role of proinflammatory cytokines in IDPN-induced liver and kidney toxicities in rats. Rats were treated with saline (control) and IDPN (100 mg/kg, intraperitoneally) daily for 1, 5, and 10 days, respectively. Animals were killed 24 hours after the last dose and liver and kidneys were collected for histopathology and interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α messenger RNA expression analysis. Serum aspartate aminotransferase and alanine aminotransferase activities were significantly increased after 10 doses of IDPN. The level of serum creatinine was initially increased after the first dose of IDPN but subsided on days 5 and 10. Blood urea nitrogen levels were significantly increased on days 5 and 10 following IDPN exposure. Histopathology showed dose-dependent hepatotoxicity in IDPN-treated rats. Iminodipropionitrile-induced expression of proinflammatory cytokines peaked after day 1 in liver and after day 5 in kidneys. In conclusion, repeated exposure of IDPN for 10 days produced significant structural and functional damages in rat liver whereas kidneys showed gradual recovery with time. These findings point toward the role of inflammatory mediators in IDPN-induced toxicity in rats.

Pattern of neurobehavioral and organ-specific toxicities of β, β'-iminodipropionitrile in mice

INTRODUCTION

β, β'-iminodipropionitrile (IDPN) is a synthetic nitrile that produces a permanent movement disorder in rodents. Although IDPN-induced vestibular pathology is well documented, the mode of IDPN interaction with other organ systems is poorly understood. We examined the behavioral signs and histopathological changes in the vestibular labyrinth, brain, liver and kidneys of mice exposed to IDPN.

MATERIAL AND METHODS

Adult male SWR/J mice were divided into 2 groups of 6 animals each. One group of mice received normal saline (control group) and the other group was treated with IDPN (400 mg/kg, i.p.) daily for 7 days. Dyskinetic movements including vertical and horizontal head weaving, circling and backward walking were quantified on days 7, 8 and 9.

RESULTS

We observed a direct correlation between the severity of IDPN-induced behavioral deficits and the degeneration of vestibular hair cells in the crista ampullaris of mice. The brain cortex of both groups appeared similar, whereas the kidney histopathology revealed mild nephrotoxicity in some of the IDPN-treated mice. Administration of IDPN caused severe hepatotoxicity, but the intensity of hepatic damage was not correlated with the severity of behavioral deficits.

CONCLUSIONS

Degeneration of vestibular sensory hair cells plays an important role in the development of IDPN-induced behavioral deficits in mice. Exposure to IDPN also caused severe hepatotoxicity which was independent of the behavioral symptoms. These findings could be of potential relevance to human health, particularly after the observation that IDPN not only causes a movement disorder but also produces acute liver injury.

Ameliorative effect of gastrodin on 3,3'-iminodipropionitrile-induced memory impairment in rats

3,3'-Iminodipropionitrile (IDPN), one of the nitrile derivatives inducing neurotoxicity, causes the dyskinetic syndrome and cognitive impairment. Gastrodin is widely used to treat neurological disorders and showed to improve cognitive functions. The present study aimed to determine whether treatment with gastrodin can attenuate IDPN-induced impairment of memory consolidation in the passive avoidance (PA) task, and to explore the possible neural mechanisms. Our results showed that intragastric administration of gastrodin (200mg/kg) reversed the IDPN-induced impairment of memory consolidation as indicated by the prolonged retention latency in the PA task. Furthermore, gastrodin reverted IDPN-induced reduction of serotonin (5-HT) and elevation of serotonin turnover ratio. Gastrodin treatment prevented the increase of serotonin transporter (SERT) and the decrease of serotonin 1A (5-HT1A) receptor expression in the hippocampus of IDPN-treated rats. These results suggest that long-term gastrodin treatment could represent a novel pharmacological strategy for IDPN-induced memory impairment, as well that its protective effect is mediated through normalization of the serotoninergic system.

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

Dopamine (DA) is a key neuromodulator in the brain that supports motor and cognitive functions. Here, we use apomorphine (Apo) and 3,3'-iminodipropionitrile (IDPN) to develop two rat models of Tourette's syndrome (TS), a common neuropsychiatric disorder characterized by stereotyped repetitive involuntary tics. The models enabled the assessment of unique ameliorative effects of Ningdong granule (NDG), a traditional Chinese medicine (TCM) preparation dedicated to the treatment of TS, on the striatal DA content of rats. By using high-performance liquid chromatography (HPLC), we found that long-term administration of NDG could, at least partially, restore the striatal dopamine alterations, either by increasing them after IDPN treatment or by decreasing them after Apo treatment. Taken together, our data indicated that NDG could ameliorate the abnormal striatal DA content dually, and the unique therapeutic property may be meaningful for the treatment of TS.

Gastrodin ameliorates memory deficits in 3,3'-iminodipropionitrile-induced rats: possible involvement of dopaminergic system

3,3'-Iminodipropionitrile (IDPN), one of the nitrile derivatives, can induce neurotoxicity, and therefore cause motor dysfunction and cognitive deficits. Gastrodin is a main bioactive constituent of a Chinese herbal medicine (Gastrodia elata Blume) widely used for treating various neurological disorders and showed greatly improved mental function. This study was designed to determine whether administration of gastrodin attenuates IDPN-induced working memory deficits in Y-maze task, and to explore the underlying mechanisms. Results showed that exposure to IDPN (150 mg/kg/day, v.o.) significantly impaired working memory and that long-term gastrodin (200 mg/kg/day, v.o.) could effectively rescue these IDPN-induced memory impairments as indicated by increased spontaneous alternation in the Y-maze test. Additionally, gastrodin treatment prevented IDPN-induced reductions of dopamine (DA) and its metabolites, as well as elevation of dopamine turnover ratio (DOPAC + HVA)/DA. Gastrodin treatment also prevented alterations in dopamine D2 receptor and dopamine transporter protein levels in the rat hippocampus. Our results suggest that long-term gastrodin treatment may have potential therapeutic values for IDPN-induced cognitive impairments, which was mediated, in part, by normalizing the dopaminergic system.

Histological insights in iminodipropionitrile-induced toxicity in rats

Iminodipropionitrile (IDPN) is a prototype nitrile compound that produces excitation, chorea and circling (ECC) syndrome in rodents. Previous studies have implicated vestibular hair cell degeneration in IDPN-induced behavioral abnormalities. Although the pathological changes in vestibular labyrinth of IDPN-treated rats are well documented, the effects of IDPN on other organ systems are not clearly understood. We therefore examined the histopathological alterations in inner ear, brain, liver and kidneys of rats exposed to IDPN. Adult male Wistar rats were divided into two groups of six animals each. Control rats received normal saline whereas the IDPN group was treated with IDPN (100mg/kg, i.p.) daily for 7 days. All the animals were carefully observed for any behavioral abnormality and the dyskinetic movements including the vertical and horizontal head weaving, circling and backward walking were quantified. The animals were sacrificed on day 9 and the samples of cochlea, brain, liver and kidney were collected for histopathology. The results showed a direct correlation between the severity of behavioral deficits and the cellular damage in crista ampullaris in IDPN-treated rats. Histopathology of liver was severely influenced by IDPN treatment, leading to vacuolization of cytoplasm, distorted sinusoids, infiltration of mononuclear cells and necrotic zones. However, the severity of hepatic damage in IDPN-treated rats was independent of the magnitude of vestibular hair cell degeneration as well as the severity of behavioral deficits. Administration of IDPN in the vestibulotoxic doses did not produce any histological changes in the brain cortex and kidneys of rats.