Curcumin alleviates orofacial allodynia and improves cognitive impairment via regulating hippocampal synaptic plasticity in a mouse model of trigeminal neuralgia.

OBJECTIVE: Cognitive impairment, one of the most prevalent complications of trigeminal neuralgia, is troubling for patients and clinicians due to limited therapeutic options. Curcumin shows antinociception and neuroprotection pharmacologically, suggesting that it may have therapeutic effect on this complication. This study aimed to investigate whether curcumin alleviates orofacial allodynia and improves cognitive impairment by regulating hippocampal CA1 region synaptic plasticity in trigeminal neuralgia. METHODS: A mouse model of trigeminal neuralgia was established by partially transecting the infraorbital nerve (pT-ION). Curcumin was administered by gavage twice daily for 14 days. Nociceptive thresholds were measured using the von Frey and acetone test, and the cognitive functions were evaluated using the Morris water maze test. Dendritic spines and synaptic ultrastructures in the hippocampal CA1 area were observed by Golgi staining and transmission electron microscopy. RESULTS: Curcumin intervention increased the mechanical and cold pain thresholds of models. It decreased the escape latency and distance to the platform and increased the number of platform crossings and dwell time in the target quadrant of models, and improved spatial learning and memory deficits. Furthermore, it partially restored the disorder of the density and proportion of dendritic spines and the abnormal density and structure of synapses in the hippocampal CA1 region of models. CONCLUSION: Curcumin alleviates abnormal orofacial pain and cognitive impairment in pT-ION mice by a mechanism that may be related to the synaptic plasticity of hippocampal CA1, suggesting that curcumin is a potential strategy for repairing cognitive dysfunction under long-term neuropathic pain conditions.

Ring Finger Protein 146-mediated Long-chain Fatty-acid-Coenzyme a Ligase 4 Ubiquitination Regulates Ferroptosis-induced Neuronal Damage in Ischemic Stroke.

Ischemic stroke (IS) is one of the leading causes of disability and death worldwide. Long-chain fatty-acid-coenzyme A ligase 4 (ACSL4) is a critical isozyme for ferroptosis that participates in the progression of IS. RING finger protein 146 (RNF146) is an E3 ligase predicted to interact with ACSL4 and regulated by activating transcription factor 3 (ATF3). The molecular mechanism of the RNF146/ACSL4 axis in IS is still unclear. Oxygen-glucose deprivation/reperfusion (OGD/R) treatment was used as the in vitro model, and middle cerebral artery occlusion (MCAO) mice were established for the in vivo model for IS. The protein level of ACSL4 was monitored by Western blot during ischemic injury. RNF146 was overexpressed in vitro and in vivo. The interaction of RNF146 and ACSL4 was determined by co-immunoprecipitation (Co-IP) assay. Chromatin immunoprecipitation (ChIP) assay and luciferase assay were utilized to determine the regulation of ATF3 on RNF146. Ferroptosis was evaluated by the levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), Fe2+, and protein levels of related genes including ACSL4, SLC7A11, and GPX4. ACSL4 was downregulated upon OGD treatment and then increased by re-oxygenation. RNF146 was responsible for the ubiquitination and degradation of ACSL4 protein. RNF146 overexpression could prevent the stimulation of OGD/R-induced LDH, MDA, and Fe2+ levels and ferroptosis-related gene expression. ATF3 could activate the transcription and expression of RNF146, leading to the inhibition of OGD/R-induced neuron ferroptosis. The ATF3-mediated RNF146 could alleviate neuronal damage in IS by regulating ACSL4 ubiquitination and ferroptosis, providing a novel theoretical basis for exploring therapeutic targets and strategies.

Saikosaponin A improved depression-like behavior and inhibited hippocampal neuronal apoptosis after cerebral ischemia through p-CREB/BDNF pathway.

Post-stroke depression(PSD) is a common complication and associates with poor physical recovery, low quality of life and high mortality after cerebral infarction. However, the pathogenesis of PSD have not been elucidated thoroughly now, and there is a lack of effective therapy in clinic. It reported that Saikosaponin A, one of the main constituents from Chinese herb Bupleurum chinense, has pharmacological activity in anti-depression. Thus, this study aimed to elucidate the potential effects and mechanisms of Saikosaponin A on the depression-like behavior after cerebral ischemic injury in rats. The rat model of PSD was induced by middle cerebral artery occlusion(MCAO) combined with chronic unpredictable mild stress(CUMS) and isolation. Behavior tests including open field test, beam-walking test, sucrose preference and forced swimming tests were performed. Western blot and immunohistochemistry were adopted to evaluate expression of phosphorylated cAMP response element binding protein(p-CREB), brain derived neurotrophic factor(BDNF) and apoptosis-related molecules in the dentate gyrus region of rat hippocampus. The TUNEL assay was used to determine neuronal apoptosis. We found that the rats subjected to MCAO combined with CUMS and isolation experienced significant depressive-like behavior. Administration of Saikosaponin A significantly ameliorated depressive-like behavior, and inhibited neuronal apoptosis, enhanced the level of p-CREB, BDNF and Bcl-2, reduced the level of Bax, Caspase-3 in the hippocampus of PSD rats. These results revealed that Saikosaponin A improved depression-like behavior and inhibited hippocampal neuronal apoptosis after cerebral ischemia, presumably through increasing the expression of BDNF, p-CREB and Bcl-2, as well as decreasing the level of Bax, Caspase-3.

Effect and Safety of Hydroxysafflor Yellow A for Injection in Patients with Acute Ischemic Stroke of Blood Stasis Syndrome: A Phase II, Multicenter, Randomized, Double-Blind, Multiple-Dose, Active-Controlled Clinical Trial.

OBJECTIVE: To assess the effect and safety of Hydroxysafflor Yellow A for Injection (HSYAI) in treating patients with acute ischemic stroke (AIS) and blood stasis syndrome (BSS). METHODS: A multicenter, randomized, double-blind, multiple-dose, active-controlled phase II trial was conducted at 9 centers in China from July 2013 to September 2015. Patients with moderate or severe AIS and BSS were randomly assigned to low-, medium-, high-dose HSYAI groups (25, 50 and 70 mg/d HSYAI by intravenous infusion, respectively), and a control group (Dengzhan Xixin Injection (, DZXXI) 30 mL/d by intravenous infusion), for 14 consecutive days. The primary outcome was the Modified Rankin Scale (mRS) score ⩽1 at days 90 after treatment. The secondary outcomes included the National Institute of Health Stroke Scale (NIHSS) score ⩽1, Barthel Index (BI) score ⩾95, and BSS score reduced ⩾30% from baseline at days 14, 30, 60, and 90 after treatment. The safety outcomes included any adverse events during 90 days after treatment. RESULTS: Of the 266 patients included in the effectiveness analysis, 66, 67, 65 and 68 cases were in the low-, medium-, and high-dose HSYAI and control groups, respectively. The proportions of patients in the medium- and high-dose HSYAI groups with mRS score ⩽1 at days 90 after treatment were significantly larger than the control group (P<0.05). The incidences of favorable outcomes of NIHSS and BI at days 90 after treatment as well as satisfactory improvement of BSS at days 30 and 60 after treatment in the medium- and high-dose HSYAI groups were all significantly higher than the control group (P<0.05). No significant difference was reported among the 4 groups in any specific adverse events (P>0.05). CONCLUSIONS: HSYAI was safe and well-tolerated at all doses for treating AIS patients with BSS. The medium (50 mg/d) or high dose (75 mg/d) might be the optimal dose for a phase III trial. (Registration No. ChiCTR-2000029608).

Antidepressant-like effects of paeoniflorin on post-stroke depression in a rat model.

BACKGROUND: Post-stroke depression (PSD) is one of the most prevalent emotional disorders after stroke and often results in poor outcomes. However, the underlying physiopathologic mechanism and effective treatment of PSD remain poorly elucidated. OBJECTIVE: To investigate whether paeoniflorin has antidepressant-like activity in a rat model of PSD. METHODS: Rats were randomly divided into four groups: sham-operated control (Sham), PSD, paeoniflorin (with PSD) and fluoxetine group(with PSD). PSD was developed by the right middle cerebral artery occlusion followed 21 days chronic unpredictable mild stress combined (CUMS) with raised alone. Tests of sucrose preference and open field were used to assess the depression-like behavior. Neurological function was evaluated by neurological deficit score and beam balance test. Expression of phosphorylated CREB (p-CREB) and brain-derived neurotrophic factor (BDNF) in the CA1 region of the hippocampal complex was evaluated by western blot and immunofluorescence. RESULTS: Te depressive-like behaviors markedly improved after paeoniflorin and fluoxetine treatment. Furthermore, paeoniflorin treatment significantly increased BDNF and p-CREB expression in the CA1 region. CONCLUSIONS: Observed results suggested that paeoniflorin could ameliorate the symptoms and improve the functional capability of PSD rats, similar to the effect of fluoxetine. ABBREVIATIONS: PSD: post-stroke depression; CUMS: chronic unpredictable mild stress stimulation; MCAO: middle cerebral artery occlusion; OFT: open field test; SPT: sucrose preference test, NDS: neurological deficit score, BBT: beam balance test; BDNF: brain-derived neurotrophic factor protein; p-CREB: phosphorylated Cyclic-AMP responsive element binding protein.

Fastigial nucleus electrostimulation promotes axonal regeneration after experimental stroke via cAMP/PKA pathway.

Axon regeneration after cerebral ischemia in mammals is inadequate to restore function, illustrating the need to design better strategies for improving outcomes. Improvement of axon regeneration has been achieved through fastigial nucleus electrostimulation (FNS) in animal researches. However, the mechanisms underlying this neuroprotection remain poorly understood. Increasing the levels of the second messenger cyclic AMP (cAMP) enhances axon regeneration, making it an excellent candidate molecule that has therapeutic potential. In the present study, we examined the expression of cAMP signaling in ischemic brain tissues following focal cerebral ischemia. Adult rats were subjected to ischemia induced by middle cerebral artery occlusion (MCAO). A dipolar electrode was placed into the cerebellum to stimulate the cerebellar fastigial nucleus for 1 h after ischemia. Neurological deficits and the expressions of cAMP, PKA (protein kinase A) and ROCK (Rho-kinase) were determined. Axonal regeneration was measured by upregulation of growth-associated protein 43 (GAP43). The data indicated that FNS significantly enhanced axonal regeneration and motor function recovery after cerebral ischemia. FNS also significantly increased cAMP and PKA levels after ischemic brain injury. All the beneficial effects of FNS were blocked by Rp-cAMP, an antagonist of PKA. Our research suggested that the axonal regeneration conferred by FNS was likely achieved via the regulation of cAMP/PKA pathway.

Ultra-wideband filtering of spoof surface plasmon polaritons using deep subwavelength planar structures.

Novel ultra-wideband filtering of spoof surface plasmon polaritons (SPPs) is proposed in the microwave frequency using deep subwavelength planar structures printed on thin and flexible dielectric substrate. The proposed planar SPPs waveguide is composed of two mirror-oriented metallic corrugated strips, which are further decorated with parallel-arranged slots in the main corrugated strips. This compound structure provides deep subwavelength field confinement as well as flexible parameters when employed as a plasmonic waveguide, which is potential to construct miniaturization. Using momentum and impedance matching technology, we achieve a smooth conversion between the proposed SPPs waveguide and the conventional transmission line. To verify the validity of the design, we fabricate a spoof SPPs filter, and the measured results illustrate excellent performance, in which the reflection coefficient is less than -10 dB within the -3 dB passband from 1.21 GHz to 7.21 GHz with the smallest insertion loss of 1.23 dB at 2.21 GHz, having very good agreements with numerical simulations. The ultra-wideband filter with low insertion loss and high transmission efficiency possesses great potential in modern communication systems.