BackgroundDepression has most often been diagnosed in patients with temporal lobe epilepsy (TLE), but the mechanism underlying this association remains unclear. In this study, we report that indoleamine 2,3-dioxygenase 1 (IDO1), a rate-limiting enzyme in tryptophan metabolism, plays a key role in epilepsy-associated depressive-like behavior.MethodsRats which develop chronic epilepsy following pilocarpine status epilepticus exhibited a set of interictal disorders consistent with depressive-like behavior. Changes of depressive behavior were examined by taste preference test and forced swim test; brain IL-1β, IL-6 and IDO1 expression were quantified using real-time reverse transcriptase PCR; brain kynurenine/tryptophan and serotonin/tryptophan ratios were analyzed by liquid chromatography-mass spectrometry. Oral gavage of minocycline or subcutaneous injection of 1-methyltryptophan (1-MT) were used to inhibite IDO1 expression.ResultsWe observed the induction of IL-1β and IL-6 expression in rats with chronic TLE, which further induced the upregulation of IDO1 expression in the hippocampus. The upregulation of IDO1 subsequently increased the kynurenine/tryptophan ratio and decreased the serotonin/tryptophan ratio in the hippocampus, which contributed to epilepsy-associated depressive-like behavior. The blockade of IDO1 activation prevented the development of depressive-like behavior but failed to influence spontaneous seizures. This effect was achieved either indirectly, through the anti-inflammatory tetracycline derivative minocycline, or directly, through the IDO antagonist 1-MT, which normalizes kynurenine/tryptophan and serotonin/tryptophan ratios.ConclusionBrain IDO1 activity plays a key role in epileptic rats with epilepsy-associated depressive-like behavior.
Background: Previous neuroimaging studies have revealed that acupuncture modulates the default mode network (DMN) in healthy subjects and patients with certain disorder. However, few studies have been performed to investigate whether or not acupuncture might modulate the DMN in patients with major depressive disorder (MDD). Thereby, the aim of the present study was to assess alterations of the DMN induced by acupuncture stimulation in patients with first-episode, drug-naïve MDD.Materials and Methods: Twenty nine patients with first-episode, drug-naïve MDD and 29 healthy subjects were enrolled in this study. All the healthy subjects underwent 6-min resting-state functional magnetic resonance imaging (R-fMRI) scan. While patients underwent acupuncture stimulation for 20-min electro-acupuncture stimulation (EAS) at Baihui acupoint (GV20) and two 6-min R-fMRI scans before and after EAS. Based on the precuneus/posterior cingulate cortex (PC/PCC) as the seed region, functional connectivity (FC) method was adopted to examine abnormal DMN in patients by comparing with healthy subjects and to evaluate the influence of EAS on intrinsic connectivity within the DMN in patients with MDD.Results: Compared to healthy subjects, MDD patients had abnormal DMN. Moreover, results showed that EAS at GV20 induced increased FC between the PC/PCC and bilateral anterior cingulate cortex (ACC), and decreased FC between the PC/PCC and left middle prefrontal cortex, left angualr gyrus and bilateral hippocampus/parahippocampus (HIPP/paraHIPP) in patients with MDD, which were the main brain regions showing significant differences between the patients and healthy subjects.Conclusion: Our findings provide imaging evidence to support that GV20-related acupuncture stimulation may modulate the DMN in patients with first-episode, drug-naïve MDD. This study may partly interpret the neural mechanisms of acupuncture at GV20 which is used to treat patients with MDD in clinical.
Background: Epilepsy is a chronic neurological disorder affecting an estimated 50 mil-lion people worldwide. Emerging evidences have accumulated over the past decades supporting the role of inflammation in the pathogenesis of epilepsy. Curcumin is a nature-derived active molecule demonstrating anti-inflammation efficacy. However, its effects on epilepsy and corresponding mech-anisms remain elusive.Objective: To investigate the effects of curcumin on epilepsy and its underlying mechanism.Method: Forty Sprague Dawley rats were divided into four groups: (1) control group; (2) Kainic Acid (KA)-induced epilepsy group; (3) curcumin group; and (4) curcumin pretreatment before KA stimulation group. Morris water maze was utilized to assess the effect of curcumin on KA-induced epilepsy. The hippocampi were obtained from rats and subjected to western blot. Immunohistochem-istry was conducted to investigate the underlying mechanisms.Results: Rats received curcumin demonstrated improvement of recognition deficiency and epilepsy syndromes induced by KA. Western blot showed that KA stimulation increased the expression of IL-1β and NLRP3, which were reduced by curcumin treatment. Further investigations revealed that curcumin inhibited the activation of NLPR3/inflammasome in epilepsy and reduced neuronal loss in hippocampus.Conclusion: Curcumin inhibits KA-induced epileptic syndromes via suppression of NLRP3 in-flammasome activation; therefore, offers a potential therapy for epilepsy.
Summary of Background Data: Depression is one of the most common comorbidities in patients with chronic low back pain. However, the mechanisms of depression in chronic low back pain patients and the effect of antidepressants on the comorbidity of pain and depression need to be further explored. The establishment of the appropriate animal models and of more effective therapies is critical for this comorbidity. Lumbar disc herniation (LDH) is the most common disease that causes low back pain. The current study examined whether an LDH model shows behavioral and biochemical alterations that are in accordance with the characteristics of the comorbidity of pain and depression and tested the effect of fluoxetine (FLX) on these measures.Objective: The current study examined whether an LDH model showed the behavioral and biochemical alterations that were in accordance with the characteristics of the comorbidity of pain and depression and tested the effect of FLX on these measures.Methods: The LDH animal model was generated by the implantation of the autologous nucleus pulposus on the left L5 nerve root just proximal to the dorsal root ganglion in Wistar rats. Pain intensity was evaluated by mechanical allodynia and thermal hyperalgesia, and changes in depressive behavior were examined by the taste preference and forced swim tests. Hippocampal serotonin (5-HT) levels were measured by liquid chromatography-mass spectrometry, and tumor necrosis factor-α (TNF-α) mRNA was quantified using real-time reverse transcriptase PCR.Results: LDH resulted in chronic pain, which further induced depressive behavior that persisted for 6 weeks after surgery. There were decreased 5-HT concentrations and upregulated TNF-α mRNA levels that were accompanied by behavioral changes. FLX treatment improved depressive behavior and moderately alleviated pain through increased 5-HT concentrations, and inhibited TNF-α mRNA expression.Conclusions: In summary, our studies provide initial evidence that the LDH chronic pain model might serve as a model of the comorbidity of low back pain and depression. The finding that FLX improved depressive behavior and pain through normalized 5-HT concentrations and TNF-α mRNA expression establishes the initial mechanism of the comorbidity of pain and depression.
Background: Alzheimer’s disease (AD) has affected numerous elderly individuals worldwide. Panax notoginseng has been shown to ameliorate AD symptoms, and notoginsenoside R2 is a key saponin identified in this plant. Purpose: In the current study, we aimed to explore whether notoginsenoside R2 could improve the prognosis of AD. Methods: Herein, primary rat cortical neurons were isolated and they were treated with amyloid beta-peptide (A β) 25–35 oligomers. Cellular apoptosis was examined via flow cytometry and Western blotting. miR-27a and SOX8 mRNA expression levels were quantified by quantitative reverse transcription-polymerase chain reaction. Furthermore, the interaction between miR-27a and SOX8 was investigated by utilizing a dual-luciferase reporter assay. Finally, an AD mouse model was established to validate the in vitro findings. Results: Notoginsenoside R2 alleviated A β25-35-triggered neuronal apoptosis and inflammation. During this process, miR-27a expression was decreased by notoginsenoside R2, and miR-27a negatively modulated SOX8 expression. Furthermore, activation of SOX8 upregulated β-catenin expression, thus suppressing apoptosis and neuroinflammation. Conclusions: Our animal experiments revealed that notoginsenoside R2 enhanced the cognitive function of AD mice and inhibited neuronal apoptosis. Notoginsenoside R2 ameliorated AD symptoms by reducing neuronal apoptosis and inflammation, thus suggesting a novel direction for AD pharmacotherapy.
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