Quercetin Attenuates Neuropathic Pain in Rats with Spared Nerve Injury

Quercetin is a flavonoid widely found in plants and marketed to the public as a supplement. Several studies have reported its effect on glial cells. This study aimed to examine the effect of quercetin on the development of neuropathic pain and the underlying mechanism in a spared nerve injury (SNI) rat model. Male Sprague-Dawley rats randomly assigned to the control or the quercetin group were subjected to SNI of the sciatic nerve. We measured pain behaviors on the hind paw and glial fibrillary acidic protein (GFAP) in the dorsal root ganglion (DRG) and spinal cord. Oral administration of 1% quercetin, begun before surgery, attenuated mechanical allodynia compared to the control group at days 7 and 10 after SNI. On the other hand, established pain was not attenuated in a post-dose group in which quercetin was begun 7 days after SNI. Quercetin inhibited GFAP in the satellite glial cells of the ipsilateral L5 DRG on day 7 compared to the control group. Quercetin suppressed the development of neuropathic pain through a mechanism partly involving the inhibition of satellite glial cells. As its safety is well established, quercetin has great potential for clinical use in pain treatment

A Multidisciplinary Approach to the Management of Chronic Pain through a Self-managed Behavioral Exercise Program : A Pilot Study in Japan

We conducted this study to determine the short-term treatment outcomes of multidisciplinary approaches to chronic pain management for outpatients in Japan. We evaluated pain reduction and improvement in quality of life (QOL) after treatment. We analyzed 32 patients who had experienced intractable chronic pain for > 3 months. The patients received multidisciplinary therapeutic self-managed exercise instructions and then underwent evaluations 1 and 3 months after the treatment. We used the Pain Disability Short Form-36 (SF-36), Pain Catastrophizing Scale (PCS), and Pain Disability Assessment Scale (PDAS) to evaluate QOL. Although the pain levels were the same before and after the physical exercise program, the patients showed significant improvements in physical function on the SF-36 (48.5 vs. 54.5, 3 months vs. 1 month; p=0.0124), the magnification subscale on the PCS (6.8 vs. 5.9, 1 month vs. before; p=0.0164) and the PDAS (29.2 vs. 23.4, 3 months vs. before; p=0.0055). Chronic pain should be treated with a biopsychosocial approach, but time constraints and costs have limited the implementation of multidisciplinary and behavioral approaches to chronic pain management. Our findings demonstrate that clinical improvements are possible for patients with chronic pain, using multidisciplinary team resources widely available in Japanese clinical practice

Monolayer Modification of Spherical Amorphous Silica by Clay Nanosheets

Clay-silica nanocomposite materials (CSiN) were prepared by an electrostatic interaction between negatively charged clay nanosheets and positively charged spherical silica, which was modified with an alkyl ammonium group by silane coupling. By optimization of the preparation conditions, 84% coverage of the silica surface by the clay nanosheets was achieved. Adsorption experiments using cationic porphyrin dyes on the CSiN revealed that the clay nanosheet covers the spherical silica as a single layer and does not detach from the silica surface under aqueous conditions. In addition, it turned out that the cationic porphyrin dye did not penetrate the space between the silica surface and the clay nanosheet. Porphyrin molecules were adsorbed only at the outer surface of the clay nanosheet without molecular aggregation even under the high-density adsorption conditions. By combining spherical silica and clay nanosheets, it is possible to prepare novel hybrid materials where the surface can act as a unique adsorption field for dyes

Enhanced Fluorescence behavior of Safranine-O by complexing with inorganic clay nanosheets

Our laboratory has been studying the strong enhancement in the fluorescence quantum yield and an excited lifetime of the organic dye molecules on the clay nanosheets and refer to as “Surface-Fixation Induced Emission”. In this study, Safranine-O which is a mono-cationic phenazine-based dye molecule, was used as the organic dye. It has fluorescence enhancement properties on the clay surface due to the suppression of the non-radiative deactivation rate constant (knr) on the clay nanosheets. While Safranine-O in water in the absence of clay nanosheets exhibited the values as 0.068 and 1.09 × 10−9 s for ϕf and τ, those on the clay surface are 0.121 and 1.96 × 10−9 s. knr values in water and on the clay were calculated to be 8.6 × 108 s − 1 and 4.5 × 108 s − 1, respectively. These results can be explained well by the structure fixing and structure resembling effect. This study helps to explore the possibility of utilizing mono-cationic dye molecules for the realization of desired photo-functional materials and photochemical reactions