L-Cysteine attenuates osteopontin-mediated neuroinflammation following hypoxia-ischemia insult in neonatal mice by inducing S-sulfhydration of Stat3.

We previously show that L-Cysteine administration significantly suppresses hypoxia-ischemia (HI)-induced neuroinflammation in neonatal mice through releasing H2S. In this study we conducted proteomics analysis to explore the potential biomarkers or molecular therapeutic targets associated with anti-inflammatory effect of L-Cysteine in neonatal mice following HI insult. HI brain injury was induced in postnatal day 7 (P7) neonatal mice. The pups were administered L-Cysteine (5 mg/kg) at 24, 48, and 72 h post-HI. By conducting TMT-based proteomics analysis, we confirmed that osteopontin (OPN) was the most upregulated protein in ipsilateral cortex 72 h following HI insult. Moreover, OPN was expressed in CD11b+/CD45low cells and infiltrating CD11b+/CD45high cells after HI exposure. Intracerebroventricular injection of OPN antibody blocked OPN expression, significantly attenuated brain damage, reduced pro-inflammatory cytokine levels and suppressed cerebral recruitment of CD11b+/CD45high immune cells following HI insult. L-Cysteine administration reduced OPN expression in CD11b+/CD45high immune cells, concomitant with improving the behavior in Y-maze test and suppressing cerebral recruitment of CD11b+/CD45high immune cells post-HI insult. Moreover, L-Cysteine administration suppressed the Stat3 activation by inducing S-sulfhydration of Stat3. Intracerebroventricular injection of Stat3 siRNA not only decreased OPN expression, but also reversed HI brain damage. Our data demonstrate that L-Cysteine administration effectively attenuates the OPN-mediated neuroinflammation by inducing S-sulfhydration of Stat3, which contributes to its anti-inflammatory effect following HI insult in neonatal mice. Blocking OPN expression may serve as a new target for therapeutic intervention for perinatal HI brain injury.

RIP3 Inhibition ameliorates chronic constriction injury-induced neuropathic pain by suppressing JNK signaling.

Neuroinflammation is a major contributor to neuropathic pain. Receptor interacting serine/threonine kinase 3 (RIP3) senses cellular stress, promotes inflammatory responses and activates c-Jun N-terminal kinase (JNK) signaling. Here, we assessed the involvement of RIP3-induced JNK signaling in chronic constriction injury (CCI)-induced neuropathic pain. We found that RIP3 inhibitors (GSK'872) and JNK inhibitors (SP600125) not only alleviated the radiant heat response and mechanical allodynia in CCI rats, but also reduced inflammatory factor levels in the lumbar spinal cord. CCI surgery induced RIP3 mRNA and protein expression in the spinal cord. GSK'872 treatment after CCI surgery reduced RIP3 and phosphorylated (p)-JNK expression in the spinal cord, whereas SP600125 treatment after CCI surgery had almost no effect on RIP3. Sinomenine treatment reduced RIP3, p-JNK and c-Fos levels in the spinal cords of CCI rats. These data demonstrated that RIP3 inhibition (particularly via sinomenine treatment) alleviates neuropathic pain by suppressing JNK signaling. RIP3 could thus be a new treatment target in patients with neuropathic pain.

Obesity increases neuropathic pain via the AMPK-ERK-NOX4 pathway in rats.

This study focused on the relationship between extracellular-regulated kinase (ERK) and obesity-induced increases in neuropathic pain. We fed rats a high-fat diet to establish the obesity model, and rats were given surgery to establish the chronic compression of the dorsal root ganglia (CCD) model. U0126 was applied to inhibit ERK, and metformin or 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) was applied to cause AMP-activated protein kinase (AMPK) activation. Paw withdrawal mechanical threshold (PWMT) were calculated to indicate the level of neuropathic pain. The data indicated that compared with normal CCD rats, the PWMT of obese CCD rats were decreased, accompanied with an increase of ERK phosphorylation, NAD(P)H oxidase 4 (NOX4) protein expression, oxidative stress and inflammatory level in the L4 to L5 spinal cord and dorsal root ganglia (DRG). Administration of U0126 could partially elevate the PWMT and reduce the protein expression of NOX4 and the above pathological changes in obese CCD rats. In vitro, ERK phosphorylation, NOX4 protein expression increased significantly in DRG neurons under the stimulation of palmitic acid (PA), accompanied with increased secretion of inflammatory factors, oxidative stress and apoptosis level, while U0126 partially attenuated the PA-induced upregulation of NOX4 and other pathological changes. In the rescue experiment, overexpression of NOX4 abolished the above protective effect of U0126 on DRG neurons in high-fat environment. Next, we explore upstream mechanisms. Metformin gavage significantly reduced neuropathic pain in obese CCD rats. For the mechanisms, activating AMPK with metformin (obese CCD rats) or AICAR (DRG neurons in a high-fat environment) not only inhibited the ERK-NOX4 pathway, but also improved oxidative stress and inflammation caused by high-fat. In conclusion, the AMPK-ERK-NOX4 pathway may has a pivotal role in mediating obesity-induced increases in neuropathic pain.

DOK3 is involved in microglial cell activation in neuropathic pain by interacting with GPR84.

Adaptor molecule downstream of kinase-3 (DOK3) is a vital regulator of innate immune responses in macrophages and B cells, and G-protein-coupled receptor 84 (GPR84) is significant in mediating the biosynthesis and maintenance of inflammatory mediators that are induced by neuropathic pain in microglia. In the present study, we determined the role of DOK3 in activating microglia-induced neuropathic pain and investigated the underlying mechanisms associated with GPR84. We found that knockdown of DOK3 in microglial cells dramatically reduced the levels of inflammatory factors, and we uncovered a physical association between DOK3 and GPR84 in the induction of inflammatory responses. We also observed that neuropathic pain and inflammatory responses induced by chronic constriction injury (CCI) of the sciatic nerve or intrathecal injection of a GPR84 agonist were compromised in DOK3-/- mice in vivo. Finally, enforced expression of DOK3 provoked inflammatory responses, and administration of pregabalin relieved neuropathic pain via inhibition of DOK3 expression. In conclusion, DOK3 induced neuropathic pain in mice by interacting with GPR84 in microglia. We hypothesize that targeting the adaptor protein DOK3 may open new avenues for pharmaceutical approaches to the alleviation of neuropathic pain in the spinal cord.

The Occurrence Rate of Swallowing Disorders After Stroke Patients in Asia: A PRISMA-Compliant Systematic Review and Meta-Analysis.

BACKGROUND: Swallowing disorders (dysphagia) is common in stroke patients. However, the epidemiology of post-stroke dysphagia (PSD) is poorly described. We herein synthesize the data of eligible studies on occurrence rate of dysphagia in Asian populations with stroke. METHODS: We searched the electronic databases (PubMed, Embase and Web of Science) to collect the studies on the prevalence of PSD. We used the Newcastle-Ottawa Scale (NOS) to estimate the quality of studies. The pooled dysphagia occurrence rate was obtained in Asian stroke patients. RESULTS: 40 studies (including 43 observations) from 2318 initial references were selected in the synthetic analysis. The pooled occurrence rate of dysphagia in post-stroke patients was 36.3% (95% CI, 33.3%-39.3%). Meta-regression analysis showed that the "country" and "developing level" may influence the pooled occurrence rate of PSD. CONCLUSION: Dysphagia is common in Asian post-stroke patients. Our meta-analysis may raise concern about evaluating and managing dysphagia in stroke patients.

Effect of cGMP-activated aquaporin 1 on TRPV4 in rats with allodynia induced by chronic compression of the dorsal root ganglion.

BACKGROUND: The aim of this study was to investigate the effects of aquaporin 1 (AQP1) knockdown on allodynia in rats with chronic compression of the dorsal root ganglia (DRG) and the role of TRPV4 in these effects. METHODS: Adult male Wistar rats were subjected to chronic compression of the dorsal root ganglia (CCD) via surgery. Behavioral tests were performed to calculate the paw withdrawal mechanical threshold (PWMT). Gene silence was induced by injecting rats with lentivirus expressing AQP1 short hairpin RNA (shRNA, Lv-shAQP1). Western blot analyses were performed to examine AQP1 and TRPV4 protein expression. The concentration of cyclic guanosine monophosphate (cGMP) was determined via enzyme-linked immunosorbent assay. RESULTS: AQP1 protein levels in DRG neurons were significantly increased in CCD rats and were accompanied by a decrease in the PWMT. Lentivirus-mediated RNA interference of AQP1 decreased AQP1 protein expression in CCD rats and normalized their PWMT, but not in rats infected with lentivirus-expressing negative control short hairpin RNA. Furthermore, AQP1 was identified as a cGMP-gated channel. cGMP concentration was upregulated in CCD rats. This effect was attenuated by treatment with a cGMP inhibitor. Additionally, the cGMP inhibitor decreased the mechanical allodynia and AQP1 protein expression in CCD rats. Finally, levels of TRPV4 expression were upregulated in DRG neurons and the L4/L5 spinal cord following surgery, and these effects were reversed by treatment with Lv-shAQP1 or a cGMP inhibitor. CONCLUSION: AQP1 plays a vital role in CCD-induced allodynia as Lv-shAQP1 significantly reduced the allodynia in CCD rats by inhibiting TRPV4 expression.

Early constraint-induced movement therapy affects behavior and neuronal plasticity in ischemia-injured rat brains.

Constraint-induced movement therapy is an effective rehabilitative training technique used to improve the restoration of impaired upper extremity movement after stroke. However, whether constraint-induced movement therapy is more effective than conventional rehabilitation in acute or sub-acute stroke remains controversial. The aim of the present study was to identify the optimal time to start constraint-induced movement therapy after ischemic stroke and to explore the mechanisms by which constraint-induced movement therapy leads to post-stroke recovery. Sixty-four adult male Sprague-Dawley rats were randomly divided into four groups: sham-surgery group, cerebral ischemia/reperfusion group, early constraint-induced movement therapy group, and late constraint-induced movement therapy group. Rat models of left middle cerebral artery occlusion were established according to the Zea Longa line embolism method. Constraint-induced movement therapy was conducted starting on day 1 or day 14 in the early constraint-induced movement therapy and late constraint-induced movement therapy groups, respectively. To explore the effect of each intervention time on neuromotor function, behavioral function was assessed using a balance beam walking test before surgery and at 8 and 21 days after surgery. The expression levels of brain-derived neurotrophic factor, nerve growth factor and Nogo receptor were evaluated using real time-polymerase chain reaction and western blot assay to assess the effect of each intervention time. The results showed that the behavioral score was significantly lower in the early constraint-induced movement therapy group than in the cerebral ischemia/reperfusion and late constraint-induced movement therapy groups at 8 days. At 21 days, the scores had significantly decreased in the early constraint-induced movement therapy and late constraint-induced movement therapy groups. At 8 days, only mild pyknosis appeared in neurons of the ischemic penumbra in the early constraint-induced movement therapy group, which was distinctly better than in the cerebral ischemia/reperfusion group. At 21 days, only a few vacuolated cells were observed and no obvious inflammatory cells were visible in late constraint-induced movement therapy group, which was much better than at 8 days. The mRNA and protein expression levels of brain-derived neurotrophic factor and nerve growth factor were significantly higher, but expression levels of Nogo receptor were significantly lower in the early constraint-induced movement therapy group compared with the cerebral ischemia/reperfusion and late constraint-induced movement therapy groups at 8 days. The changes in expression levels at 21 days were larger but similar in both the early constraint-induced movement therapy and late constraint-induced movement therapy groups. Besides, the protein nerve growth factor level was higher in the late constraint-induced movement therapy group than in the early constraint-induced movement therapy group at 21 days. These results suggest that both early (1 day) and late (14 days) constraint-induced movement therapy induces molecular plasticity and facilitates functional recovery after ischemic stroke, as illustrated by the histology. The mechanism may be associated with downregulation of Nogo receptor expression and upregulation of brain-derived neurotrophic factor and nerve growth factor expression.

Gene therapy by lentivirus-mediated RNA interference targeting extracellular-regulated kinase alleviates neuropathic pain in vivo.

BACKGROUNDS: Neuropathic pain is an abnormal pain, which is related to the activation of extracellular-regulated kinase (ERK) signaling. This study was to investigate the effects of ERK knockdown via lentivirus-mediated RNA interference on allodynia in rats with chronic compression of the dorsal root ganglia (DRG) and to uncover the potential mechanisms. METHODS: The model of chronic compression of the dorsal root ganglia (CCD) was established in rats by surgery. Gene silence was induced by injecting rats with lentivirus expressing ERK short hairpin RNA (shRNA). Behavioral test was performed by calculating paw withdrawal mechanical threshold (PWMT) and thermal paw withdrawal latency (TPWL). RESULTS: We firstly generated lentivirus expressing ERK shRNA to downregulate ERK gene expression both in vitro and in vivo by using Western blot analysis and quantitative reverse transcription polymerase chain reaction. In CCD, ERK mRNA, and protein levels in DRG neurons were dramatically increased, accompanied with decreased PWMT and TPWL. Lentivirus-mediated RNA interference decreased ERK gene expression in DRG neurons and normalized the PWMT and TPWL in CCD rats, but not in rats infected with lentivirus expressing negative control shRNA. Further, calcium responses of DRG neurons to the hypotonic solution and 4α-phorbol 12,13-didecanoate were enhanced in CCD rats, which were suppressed by lentivirus-mediated ERK gene silence. Finally, the levels of transient receptor potential vanilloid 4 gene expressions in DRG neurons and L4 to L5 spinal cord isolated from CCD rats were dramatically upregulated, which were reversed by lentivirus-mediated ERK gene knockdown. CONCLUSION: Lentivirus-mediated RNA interference (RNAi) silencing targeting ERK might reverse CCD-induced neuropathic pain in rats through transient receptor potential vanilloid 4.

Constraint-induced movement therapy in treatment of acute and sub-acute stroke: a meta-analysis of 16 randomized controlled trials.

OBJECTIVE: The aim of this meta-analysis was to evaluate the clinical efficacy of constraint-induced movement therapy in acute and sub-acute stroke. DATA SOURCES: The key words were stroke, cerebrovascular accident, constraint-induced therapy, forced use, and randomized controlled trial. The databases, including China National Knowledge Infrastructure, WanFang, Weipu Information Resources System, Chinese Biomedical Literature Database, PubMed, Medline, Embase, the Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews, were searched for studies on randomized controlled trials for treating acute or sub-acute stroke published before March 2016. DATA SELECTION: We retrieved relevant randomized controlled trials that compared constraint-induced movement therapy in treatment of acute or sub-acute stroke with traditional rehabilitation therapy (traditional occupational therapy). Patients were older than 18 years, had disease courses less than 6 months, and were evaluated with at least one upper extremity function scale. Study quality was evaluated, and data that met the criteria were extracted. Stata 11.0 software was used for the meta-analysis. OUTCOME MEASURES: Fugl-Meyer motor assessment of the arm, the action research-arm test, a motor activity log for amount of use and quality of movement, the Wolf motor function test, and a modified Barthel index. RESULTS: A total of 16 prospective randomized controlled trials (379 patients in the constraint-induced movement-therapy group and 359 in the control group) met inclusion criteria. Analysis showed significant mean differences in favor of constraint-induced movement therapy for the Fugl-Meyer motor assessment of the arm (weighted mean difference (WMD) = 10.822; 95% confidence intervals (95% CI): 7.419-14.226), the action research-arm test (WMD = 10.718; 95% CI: 5.704-15.733), the motor activity log for amount of use and quality of movement (WMD = 0.812; 95% CI: 0.331-1.293) and the modified Barthel index (WMD = 10.706; 95% CI: 4.417-16.966). CONCLUSION: Constraint-induced movement therapy may be more beneficial than traditional rehabilitation therapy for improving upper limb function after acute or sub-acute stroke.

MAPK Pathways Are Involved in Neuropathic Pain in Rats with Chronic Compression of the Dorsal Root Ganglion.

The aim of the present study was to investigate whether the MAPK pathways were involved in the mechanism of neuropathic pain in rats with chronic compression of the dorsal root ganglion. We determined the paw withdrawal mechanical threshold (PWMT) of rats before and after CCD surgery and then after p38, JNK, or ERK inhibitors administration. Western blotting, RT-PCR, and immunofluorescence of dorsal root ganglia were performed to investigate the protein and mRNA level of MAPKs and also the alternation in distributions of positive neurons in dorsal root ganglia. Intrathecal administration of MAPKs inhibitors, SB203580 (p38 inhibitor), SP600125 (JNK inhibitor), and U0126 (ERK inhibitor), resulted in a partial reduction in CCD-induced mechanical allodynia. The reduction of allodynia was associated with significant depression in the level of both MAPKs mRNA and protein expression in CCD rats and also associated with the decreased ratios of large size MAPKs positive neurons in dorsal root ganglia. In conclusion, the specific inhibitors of MAPKs contributed to the attenuation of mechanical allodynia in CCD rats and the large size MAPKs positive neurons in dorsal root ganglia were crucial.

Effect of TRPV4-p38 MAPK Pathway on Neuropathic Pain in Rats with Chronic Compression of the Dorsal Root Ganglion.

The aim of this study was to investigate the relationships among TRPV4, p38, and neuropathic pain in a rat model of chronic compression of the dorsal root ganglion. Mechanical allodynia appeared after CCD surgery, enhanced via the intrathecal injection of 4α-phorbol 12,13-didecanoate (4α-PDD, an agonist of TRPV4) and anisomycin (an agonist of p38), but was suppressed by Ruthenium Red (RR, an inhibitor of TRPV4) and SB203580 (an inhibitor of p38). The protein expressions of p38 and P-p38 were upregulated by 4α-PDD and anisomycin injection but reduced by RR and SB203580. Moreover, TRPV4 was upregulated by 4α-PDD and SB203580 and downregulated by RR and anisomycin. In DRG tissues, the numbers of TRPV4- or p38-positive small neurons were significantly changed in CCD rats, increased by the agonists, and decreased by the inhibitors. The amplitudes of ectopic discharges were increased by 4α-PDD and anisomycin but decreased by RR and SB203580. Collectively, these results support the link between TRPV4 and p38 and their intermediary role for neuropathic pain in rats with chronic compression of the dorsal root ganglion.

Effectiveness of Neuromuscular Electrical Stimulation on Patients With Dysphagia With Medullary Infarction.

OBJECTIVE: To evaluate and compare the effects of neuromuscular electrical stimulation (NMES) acting on the sensory input or motor muscle in treating patients with dysphagia with medullary infarction. DESIGN: Prospective randomized controlled study. SETTING: Department of physical medicine and rehabilitation. PARTICIPANTS: Patients with dysphagia with medullary infarction (N=82). INTERVENTIONS: Participants were randomized over 3 intervention groups: traditional swallowing therapy, sensory approach combined with traditional swallowing therapy, and motor approach combined with traditional swallowing therapy. Electrical stimulation sessions were for 20 minutes, twice a day, for 5d/wk, over a 4-week period. MAIN OUTCOME MEASURES: Swallowing function was evaluated by the water swallow test and Standardized Swallowing Assessment, oral intake was evaluated by the Functional Oral Intake Scale, quality of life was evaluated by the Swallowing-Related Quality of Life (SWAL-QOL) Scale, and cognition was evaluated by the Mini-Mental State Examination (MMSE). RESULTS: There were no statistically significant differences between the groups in age, sex, duration, MMSE score, or severity of the swallowing disorder (P>.05). All groups showed improved swallowing function (P≤.01); the sensory approach combined with traditional swallowing therapy group showed significantly greater improvement than the other 2 groups, and the motor approach combined with traditional swallowing therapy group showed greater improvement than the traditional swallowing therapy group (P<.05). SWAL-QOL Scale scores increased more significantly in the sensory approach combined with traditional swallowing therapy and motor approach combined with traditional swallowing therapy groups than in the traditional swallowing therapy group, and the sensory approach combined with traditional swallowing therapy and motor approach combined with traditional swallowing therapy groups showed statistically significant differences (P=.04). CONCLUSIONS: NMES that targets either sensory input or motor muscle coupled with traditional therapy is conducive to recovery from dysphagia and improves quality of life for patients with dysphagia with medullary infarction. A sensory approach appears to be better than a motor approach.

Full-movement neuromuscular electrical stimulation improves plantar flexor spasticity and ankle active dorsiflexion in stroke patients: a randomized controlled study.

OBJECTIVE: To investigate whether full-movement neuromuscular electrical stimulation, which can generate full range of movement, reduces spasticity and/or improves motor function more effectively than control, sensory threshold-neuromuscular electrical stimulation, and motor threshold-neuromuscular electrical stimulation in sub-acute stroke patients. DESIGN: A randomized, single-blind, controlled study. SETTING: Physical therapy room and functional assessment room. PARTICIPANTS: A total of 72 adult patients with sub-acute post-stroke hemiplegia and plantar flexor spasticity. METHOD: Patients received 30-minute sessions of neuromuscular electrical stimulation on the motor points of the extensor hallucis and digitorum longus twice a day, five days per week for four weeks. MEASURES: Composite Spasticity Scale, Ankle Active Dorsiflexion Score, and walking time in the Timed Up and Go Test were assessed at pretreatment, posttreatment, and at two-week follow-up. RESULTS: After four weeks of treatment, when comparing interclass pretreatment and posttreatment, only the full-movement neuromuscular electrical stimulation group had a significant reduction in the Composite Spasticity Scale (mean % reduction = 19.91(4.96)%, F = 3.878, p < 0.05) and improvement in the Ankle Active Dorsiflexion Score (mean scores = 3.29(0.91), F = 3.140, p < 0.05). Furthermore, these improvements were maintained two weeks after the treatment ended. However, there were no significant differences in the walking time after four weeks of treatment among the four groups (F = 1.861, p > 0.05). CONCLUSIONS: Full-movement neuromuscular electrical stimulation with a stimulus intensity capable of generating full movement can significantly reduce plantar flexor spasticity and improve ankle active dorsiflexion, but cannot decrease walking time in the Timed Up and Go Test in sub-acute stroke patients.

Upregulation of HIF-1α protects neuroblastoma cells from hypoxia-induced apoptosis in a RhoA-dependent manner.

Hypoxic conditions regulate several metabolic enzymes and transcription factors that are involved in cancer, ischemia and pulmonary diseases. The Ras homolog (Rho) family, including Rho member A (RhoA), is involved in reorganization of the actin cytoskeleton, cell migration and in the regulation of apoptosis and gene transcription. The aim of the present study was to investigate the expression of hypoxia­inducible factor (HIF)­α and the activity of RhoA in PC12 neuroblastoma cells under hypoxic conditions. The upregulation of HIF­α and RhoA by hypoxia was determined using reverse transcription­quantitative polymerase chain reaction and western blot assays, cell apoptosis was analyzed using flow cytometry, and the activity of caspase 3 was examined using a western blot assay and caspase 3 activity assay kit. The PC12 cells were induced to apoptosis following exposure to hypoxia, and exhibited increased expression of HIF­α and increased mRNA and protein expression levels of RhoA. The overexpression of HIF­α attenuated the hypoxia­induced apoptosis of the PC12 cells. In addition, RhoA knockdown using small interfering RNA abrogated the antagonism of HIF­1α towards hypoxia­induced apoptosis. The results of the present study confirmed the protective role of HIF­1α and RhoA in hypoxia­induced PC12 cell apoptosis, and that the upregulation of HIF­1α by hypoxia is RhoA­dependent.

Berberine via suppression of transient receptor potential vanilloid 4 channel improves vascular stiffness in mice.

Berberine, as an alkaloid found in many Chinese herbs, improves vascular functions in patients with cardiovascular diseases. We determined the effects of berberine in hypertension and vascular ageing, and elucidated the underlying mechanisms. In isolated aortas, berberine dose-dependently elicited aortic relaxation. In cultured cells, berberine induced the relaxation of vascular smooth muscle cells (VSMCs). Overexpression of transient receptor potential vanilloid 4 (TRPV4) channel by genetic approaches abolished the berberine-induced reduction in intracellular Ca(2+) concentration in VSMCs and attenuated berberine-elicited vessel dilation in mice aortas. In deoxycorticosterone acetate (DOCA)-induced hypertensive model, treatment of mice with berberine or RN-1734, a pharmacological inhibitor of TRPV4, significantly decreased systemic blood pressure (BP) in control mice or mice infected with an adenovirus vector. However, berberine-induced effects of lowering BP were reversed by overexpressing TRPV4 in mice by infecting with adenovirus. Furthermore, long-term administration of berberine decreased mean BP and pulse BP, increased artery response to vasodilator and reduced vascular collagen content in aged mice deficient in apolipoprotein E (Apoe-KO), but not in Apoe-KO old mice with lentivirus-mediated overexpression of TRPV4 channel. In conclusion, berberine induces direct vasorelaxation to lower BP and reduces vascular stiffness in aged mice through suppression of TRPV4.

A afferent fibers are involved in the pathology of central changes in the spinal dorsal horn associated with myofascial trigger spots in rats.

A afferent fibers have been reported to participate in the development of the central sensitization induced by inflammation and injuries. Current evidence suggests that myofascial trigger points (MTrPs) induce central sensitization in the related spinal dorsal horn, and clinical studies indicate that A fibers are associated with pain behavior. Because most of these clinical studies applied behavioral indexes, objective evidence is needed. Additionally, MTrP-related neurons in dorsal root ganglia and the spinal ventral horn have been reported to be smaller than normal, and these neurons were considered to be related to A fibers. To confirm the role of A fibers in MTrP-related central changes in the spinal dorsal horn, we studied central sensitization as well as the size of neurons associated with myofascial trigger spots (MTrSs, equivalent to MTrPs in humans) in the biceps femoris muscle of rats and provided some objective morphological evidence. Cholera toxin B subunit-conjugated horseradish peroxidase was applied to label the MTrS-related neurons, and tetrodotoxin was used to block A fibers specifically. The results showed that in the spinal dorsal horn associated with MTrS, the expression of glutamate receptor (mGluR1α/mGluR5/NMDAR1) increased, while the mean size of MTrS-related neurons was smaller than normal. After blocking A fibers, these changes reversed to some extent. Therefore, we concluded that A fibers participated in the development and maintenance of the central sensitization induced by MTrPs and were related to the mean size of neurons associated with MTrPs in the spinal dorsal horn.

Myelinated Afferents Are Involved in Pathology of the Spontaneous Electrical Activity and Mechanical Hyperalgesia of Myofascial Trigger Spots in Rats.

Myofascial trigger points (MTrPs) are common causes for chronic pain. Myelinated afferents were considered to be related with muscular pain, and our clinical researches indicated they might participate in the pathology of MTrPs. Here, we applied myofascial trigger spots (MTrSs, equal to MTrPs in human) of rats to further investigate role of myelinated afferents. Modified pyridine-silver staining revealed more nerve endings at MTrSs than non-MTrSs (P < 0.01), and immunohistochemistry with Neurofilament 200 indicated more myelinated afferents existed in MTrSs (P < 0.01). Spontaneous electrical activity (SEA) recordings at MTrSs showed that specific block of myelinated afferents in sciatic nerve with tetrodotoxin (TTX) led to significantly decreased SEA (P < 0.05). Behavioral assessment showed that mechanical pain thresholds (MPTs) of MTrSs were lower than those of non-MTrSs (P < 0.01). Block of myelinated afferents by intramuscular TTX injection increased MPTs of MTrSs significantly (P < 0.01), while MPTs of non-MTrSs first decreased (P < 0.05) and then increased (P > 0.05). 30 min after the injection, MPTs at MTrSs were significantly lower than those of non-MTrSs (P < 0.01). Therefore, we concluded that proliferated myelinated afferents existed at MTrSs, which were closely related to pathology of SEA and mechanical hyperalgesia of MTrSs.

Role of actin filaments in allodynia induced by chronic compression of the dorsal root ganglion.

The role of actin filaments in allodynia induced by chronic compression of the dorsal root ganglion (DRG) (CCD) and the effects of microfilaments dynamics on transient receptor potential vanilloid 4 (TRPV4) were investigated in this study. Anti-microfilaments agents resulted in dose-dependent and partial reduction in CCD-induced allodynia, which could be prevented by the prior stabilizer administration. In association with the reduction of allodynia by microfilaments' disruption, TRPV4-mediated currents were inhibited by disruptors. In addition, plasma membrane-associated TRPV4 was also depressed by disruptors. The time courses for the changes of TRPV4 activity and distribution in vitro were similar to the time courses for the attenuation of allodynia in vivo. Phalloidin, the stabilizer of microfilaments, did not affect the allodynia in CCD rats. However, phalloidin resulted in reduction and delay of TRPV4 current, which was not consistent with the effect of phalloidin on CCD-induced allodynia. In accordance with the inhibition of TRPV4 activity, the reversal potentials shifted toward more positive voltages and the plasma membrane-associated TRPV4 was depressed by phalloidin. In conclusion, intact actin filaments were necessary for CCD-induced allodynia, and disruptors of microfilaments attenuated CCD-induced allodynia. However, stabilizer of actin filaments did not affect allodynia in CCD rats. Further, TRPV4 contributed to the disruptors-induced attenuation of allodynia in CCD rats.

Yerba mate (Ilex paraguariensis) improves microcirculation of volunteers with high blood viscosity: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Elevated blood viscosity is a risk factor for atherosclerosis, thrombosis and other cardiovascular events. Our previous studies have suggested that consumption of Yerba mate tea (Ilex paraguariensis) has strong antioxidant and lipid-lowering properties in animals. The in vivo effects of Yerba mate on blood viscosity in humans, however, have not been studied. OBJECTIVE: This study aims to investigate the effect of Yerba mate tea on the reduction of blood viscosity and the improvement of microcirculatory parameters commonly regarded as risk factors for serious cardio and cerebrovascular disorders. METHODS: 142 subjects with high blood viscosity were recruited in this randomized, double-blind, placebo-controlled study. Yerba mate tea or placebo (5 g/day) was administered to different groups for 6 weeks. After treatment, results of hemorheological indexes, nailfold microcirculation, 6-keto-PGF1α and TXB2 and lipid profiles of subjects in the Yerba mate tea group were compared with those in the placebo-receiving group. RESULTS: Parameters of blood viscosity and microcirculation were improved in the subjects from the Yerba mate tea group but not in placebo-receiving patients. After treatment, whole blood viscosity, plasma viscosity and the Equation K value of erythrocyte sedimentation rate (ESRK) decreased significantly in the Yerba mate group. Meanwhile, shape, flow state and nailfold microcirculation appeared positively changed. Specifically, blood flow speeds accelerated gradually and nailfold weighted integral values decreased significantly. Moreover, the vasodilator 6-keto PGF1α increased while the thromboxane TXB2 decreased in serum samples of subjects in the Yerba mate-receiving group. Overall, Yerba mate tea-receiving subjects saw nearly all measured values improve to levels comparable to those characteristic of patients with normal microcirculation. CONCLUSIONS: These results indicate the therapeutic capacity of Yerba mate tea in the treatment of high blood viscosity. Here, Yerba mate tea played a role in the regulation of various indexes of hemorheology, nailfold microcirculation, and the platelet aggregating factors 6-keto-PGF1a and TXB2. The regulation of these might be correlated with reduced blood viscosity and accelerating blood flow. Thus, Yerba mate tea may reduce some key risk-factors of cardiovascular disease. Daily consumption of Yerba mate tea may be a better-tolerated option for individuals with high blood viscosity and microcirculatory disturbance and as such, a novel preventative strategy for patients at-risk for vascular disease.

Ca(2+) influx mediates the TRPV4-NO pathway in neuropathic hyperalgesia following chronic compression of the dorsal root ganglion.

Chronic compression of the dorsal root ganglion (DRG) (CCD) in rats is a typical model of neuropathic pain. TRPV4 contributed to mechanical allodynia induced by the CCD model. Our previous study demonstrated that TRPV4 enhances neuropathic hyperalgesia through a NO-cGMP-PKG cascade. However, the underlying mechanism(s) is still largely unknown. Therefore, the aim of the present study was to test whether TRPV4-mediated Ca(2+) influx is involved in the TRPV4-NO pathway. Regulation of intracellular calcium concentration by intrathecal injection of TRPV4-targeted siRNA significantly decreased the behavioural hyperalgesia, NF-κB activity, and NO content in CCD rats. Intraperitoneal (i.p.) injection of mibefradil significantly induced dose-dependent increases in the paw withdrawal latency (PWL) and mechanical withdrawal thresholds (MWT), as well as decreases in NF-κB activity and NO content in DRG of CCD rats. Moreover, pre-treatment with 4α-PDD attenuated the suppressive effects of mibefradil on CCD-induced neuropathic hyperalgesia, NF-κB activity, and NO production. The data showed that TRPV4-mediated Ca(2+) influx might be engaged in the TRPV4-NO pathway in neuropathic hyperalgesia in the CCD model.