Activation of spinal glial cells plays a crucial role in the pathogenesis of neuropathic pain. An administration of oxaliplatin, an important anticancer drug, often induces acute neuropathic cold hypersensitivity and/or mechanical hypersensitivity in patients. Gyejigachulbu-tang (GBT), a herbal formula comprising Cinnamomi Cortex, Paeoniae Radix, Atractylodis Lanceae Rhizoma, Zizyphi Fructus, Glycyrrhizae Radix, Zingiberis Rhizoma, and Aconiti Tuber, has been used in East Asia to treat various pain symptoms, especially in cold patients. This study investigated whether and how GBT alleviates oxaliplatin-induced cold and mechanical hypersensitivity in rats. The behavioral signs of cold and mechanical hypersensitivity were evaluated by a tail immersion test in cold water (4°C) and a von Frey hair test, respectively. The significant cold and mechanical hypersensitivity were observed 3 days after an oxaliplatin injection (6 mg/kg, i.p.). Daily oral administration of GBT (200, 400, and 600 mg/kg) for 5 days markedly attenuated cold and mechanical hypersensitivity. Immunoreactivities of glial fibrillary acidic protein (GFAP, astrocyte marker) and OX-42 (microglia marker) in the spinal dorsal horn were significantly increased by an oxaliplatin injection, which were restored by GBT administration. These results indicate that GBT relieves oxaliplatin-induced cold and mechanical hypersensitivity in rats possibly through the suppression of spinal glial activation.

This study investigated the influence of pore sizes of poly(lactic-co-glycolic acid) (PLGA) scaffolds on the compressive strength of tissue-engineered biodiscs and selection of the best suitable pore size for cells to grow in vivo. PLGA scaffolds were fabricated by solvent casting/salt-leaching with pore sizes of 90-180, 180-250, 250-355 and 355-425 µm. Nucleus pulposus (NP) cells were seeded on PLGA scaffolds with various pore sizes. Each sample was harvested at each time point, after retrieval of PLGA scaffolds seeded with NP cells, which were implanted into subcutaneous spaces in nude mice at 4 and 6 weeks. MTT assay, glycosaminoglycan (GAG) assay, haematoxylin and eosin (H&E) staining, safranin O staining and immunohistochemistry (for collagen type II) were performed at each time point. As the pores became smaller, the value of the compressive strength of the scaffold was increased. The group of scaffolds with pore sizes of 90-250 µm showed better cell proliferation and ECM production. These results demonstrated that the compressive strength of the scaffold was improved while the scaffold had pore sizes in the range 90-250 µm and good cell interconnectivity. Suitable space in the scaffold for cell viability is a key factor for cell metabolism. Copyright © 2014 John Wiley & Sons, Ltd.

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This study was performed to determine whether spinal cholinergic systems mediate the relieving effects of electroacupuncture (EA) on cold and warm allodynia in a rat model of neuropathic pain. For neuropathic surgery, the right superior caudal trunk was resected at the level between the S1 and S2 spinal nerves innervating the tail. Two weeks after the injury, the intrathecal (i.t.) catheter was implanted. Five days after the catheterization, the rats were injected with atropine (non-selective muscarinic antagonist, 30 microg), mecamylamine (non-selective nicotinic antagonist, 50 microg), pirenzepine (M(1) muscarinic antagonist, 10 microg), methoctramine (M(2) antagonist, 10 microg) or 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) (M(3) antagonist, 10 microg). Ten minutes after the injection, EA was applied to the ST36 acupoint for 30 min. The cold and warm allodynia were assessed by the tail immersion test [i.e., immersing the tail in cold (4 degrees C) or warm (40 degrees C) water and measuring the latency of an abrupt tail movement] before and after the treatments. The i.t. atropine, but not mecamylamine, blocked the relieving effects of EA on cold and warm allodynia. Furthermore, i.t. pirenzepine attenuated the antiallodynic effects of EA, whereas methoctramine and 4-DAMP did not. These results suggest that spinal muscarinic receptors, especially M(1) subtype, mediate the EA-induced antiallodynia in neuropathic rats.