Altered microRNAs expression profiling in mice with diabetic neuropathic pain.

Neuropathic pain is one of the most common chronic complications of diabetes mellitus, one hallmark of which is tactile allodynia. However, the molecular mechanisms underlying tactile allodynia are not well understood. It has been demonstrated that microRNAs (miRNAs) are essential regulators of gene expression in the nervous system where they contribute to neuronal plasticity. Thus, in this study, we investigated the differentially expressed microRNAs in the lumbar spinal dorsal horn of streptozotocin (STZ)-induced diabetic neuropathic pain (DNP) mice and vehicle controls. Results from miRNA microarrays showed that 42 miRNAs were significantly altered in DNP spinal cord tissue (P<0.05, fold change: ⩾ 2) compared with control sample. Among them, 21 miRNAs were significantly up-regulated while the other 21 down-regulated. Further validation by quantitative real-time polymerase chain reaction (qRT-PCR) indicated that the 2 significant differentially expressed candidate miRNAs (miR-184-5p and miR-190a-5p) in DNP tissue showed the same changes as in the microarray analysis. The bioinformatics analysis revealed that some of the differentially expressed miRNAs after DNP were potential regulators of some inflammation associated with genes that are known to be involved in the pathogenesis of DNP. These findings suggest that aberrant expression of miRNAs may contribute to the pathogenesis of DNP and are potential targets for therapeutic interventions following DNP.

Plasmonic filters and optical directional couplers based on wide Metal-Insulator-Metal structure.

The wide Metal-Insulator-Metal (WMIM) structure is proposed and its characteristics are analyzed numerically using finite-difference time-domain (FDTD) method. Simulations show that power can be periodically transferred between its two Metal-Insulator (MI) interfaces while power is injected asymmetrically. Novel plasmonic filters and optical directional couplers (ODCs) based on WMIM structure are proposed, which work similarly as traditional dielectric devices. Due to the simple structures without thin metal gaps, our result may provide an alternative way to realize the fabrication of nanoscale optical devices.

LncRNA expression in the spinal cord modulated by minocycline in a mouse model of spared nerve injury.

Neuropathic pain is a common and refractory chronic pain that affects millions of people worldwide. Its underlying mechanisms are still unclear, but they may involve long noncoding RNAs (lncRNAs), which play crucial roles in a variety of biological functions, including nociception. We used microarrays to investigate the possible interactions between lncRNAs and neuropathic pain and identified 22,213 lncRNAs and 19,528 mRNAs in the spinal cord in a mouse model of spared nerve injury (SNI)-induced neuropathic pain. The abundance levels of 183 lncRNAs and 102 mRNAs were significantly modulated by both SNI and administration of minocycline. A quantitative real-time polymerase chain reaction analysis validated expression changes in three lncRNAs (NR_015491, ENSMUST00000174263, and ENSMUST00000146263). Class distribution analysis of differentially expressed lncRNAs revealed intergenic lncRNAs as the largest category. Functional analysis indicated that SNI-induced gene regulations might be involved in the activities of cytokines (IL17A and IL17F) and chemokines (CCL2, CCL5, and CCL7), whereas minocycline might exert a pain-alleviating effect on mice through actin binding, thereby regulating nociception by controlling the cytoskeleton. Thus, lncRNAs might be responsible for SNI-induced neuropathic pain and the attenuation caused by minocycline. Our study could implicate lncRNAs as potential targets for future treatment of neuropathic pain.

The Effectiveness and Safety of Thermocoagulation Radiofrequency Treatment of the Ophthalmic Division (V1) and/or Maxillary (V2) and Mandibular (V3) Division in Idiopathic Trigeminal Neuralgia: An Observational Study.

BACKGROUND: Trigeminal neuralgia (TN) is a pain appearing in the ophthalmic (V1), maxillary (V2), and mandibular (V3) trigeminal branches. Pharmacologic treatment is the first line for TN; however, many patients prefer to receive minimally invasive treatment rather than medicine because of intolerable side effects. Thermocoagulation radiofrequency (TRF) is a minimally invasive treatment that has been shown to effectively treat the maxillary (V2) and mandibular (V3) divisions, but the safety of TRF treatment of the ophthalmic (V1) division has been controversial. OBJECTIVE: This study was to observe the effectiveness and safety of TRF treatment of the ophthalmic (V1) division of trigeminal branches in idiopathic TN patients. STUDY DESIGN: An observational study. SETTING: All of patients received temperature controlled TRF, the effectiveness and safety of TRF was assessed by VAS and complications. METHODS: Eighty patients with ophthalmic division (V1) or ophthalmic division (V1) combined with maxillary (V2) or mandibular (V3) divisions of idiopathic TN were treated with step-increased temperature TRF for 6 minutes. At a pulse width of 20 ms, the temperature was titrated up 2 degrees from 60 degrees to 66 degrees every 60 seconds, and then another 66 degrees or 68 degrees for 2 minutes. Meanwhile, the tip of the cannula was turned 180 degrees with each temperature titration. Patients were assessed for pain relief and corneal reflex, numbness, and masticatory muscle weakness at one week, one month, and 3 months after the procedure. RESULTS: Eighty patients were successfully treated with temperature controlled TRF for ophthalmic (V1) division. Excellent pain relief was achieved in 79 of 80 patients (98.75%) after one week, one month, and 3 months, and 78 of 80 patients (97.5%) patients experienced tolerable numbness. Only one patient lost the corneal reflex, 14 experienced a corneal reflex that was mildly decreased, and 2 patients felt a foreign body sensation in the ipsilateral eye after TRF, but there were no corneal ulcers, incidences of blindness, or other complications. LIMITATIONS: This study is limited by being an observation study and a non-prospective trial with a short-term follow-up period. CONCLUSION: Temperature controlled TRF to the ophthalmic division (V1) of the semilular ganglion is effectiveness and safe in TN. KEY WORDS: Thermocoagulation radiofrequency, pulsed radiofrequency, trigeminal neuralgia, ophthalmic division, trigeminal ganglion, pain, numbness, corneal reflex.

Src/p38 MAPK pathway in spinal microglia is involved in mechanical allodynia induced by peri-sciatic administration of recombinant rat TNF-α.

Our previous work has shown that peri-sciatic administration of recombinant rat TNF-α (rrTNF) induces mechanical allodynia and up-regulation of TNF-α in the spinal dorsal horn of rats; however, the underlying mechanisms remain unknown. In the current study, we found that the levels of phosphorylated Src-family kinases (p-SFKs) and phosphorylated p38 mitogen-activated protein kinase (p-p38 MAPK) were significantly increased in bilateral lumbar spinal dorsal horn on day 3 after rrTNF administration. Double immunofluorescence staining revealed that p-SFKs and p-p38 MAPK were nearly restricted to the microglia. Intrathecal delivery of SFKs inhibitor PP2 or p38 MAPK inhibitor SB203580, started 30 min before rrTNF administration and given once daily thereafter for 7 days, blocked mechanical allodynia in bilateral hind paws and increase of TNF-α expression in the spinal dorsal horn. Moreover, PP2 inhibited the up-regulation of p-p38 MAPK induced by rrTNF. We also found that intrathecal injection of TNF-α neutralization antibody alleviated mechanical allodynia in bilateral hind paws and suppressed up-regulation of p-SFKs and p-p38 MAPK. These results suggest that activation of the SFKs/p38 MAPK pathway in microglia and subsequent TNF-α expression in the spinal dorsal horn may contribute to the mechanical hyperalgesic state induced by peri-sciatic administered rrTNF.

[Therapeutic effect of intradiscal electrothermal therapy for discogenic low back pain].

OBJECTIVE: To observe the clinical efficacy and complications of intradiscal electrothermal therapy for treatment of discogenic low back pain. METHODS: Forty patients with discogenic low back pain were treated with intradiscal electrothermal therapy, and the changes in the VAS, functional status and complications after the treatment were analyzed. RESULTS The VAS score was decreased and the functional status improved obviously after the treatment, which caused no severe complications. CONCLUSION: Intradiscal electrothermal therapy is safe and effective to rapidly achieve pain relief and obviously improve the functional status of patients with discogenic low back pain with few complications.