Articles: hyperalgesia.
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Electroacupuncture (EA) has been shown to induce potent analgesic effects on neuropathic pain in both patients and rodents. Cell therapy to release antinociceptive agents near the pain processing centers of the spinal cord is a promising next step in the development of treatment modalities. This study investigated the effects of the combination of EA and cell therapy by glial cell line-derived neurotrophic factor (GDNF) on neuropathic pain in rats. ⋯ The results showed that the ipsilateral PWL of the rats from all three EA treatment groups significantly increased starting on the 12th day compared with the PBS control group. Strikingly, the group which received EA treatment and FBs-GDNF transplantation (CCI+EA+FBs-GDNF) showed a significantly decreased thermal hyperalgesia after 2 weeks post CCI surgery compared with the groups which received EA treatment and FBs-pLNCX2 transplantation (CCI+EA+FBs-pLNCX2) or PBS (CCI+EA+PBS) as well as the FBs-GDNF transplantation group without EA treatment (CCI+FBs-GDNF). Our data suggest that EA and cell therapy can synergistically attenuate hyperalgesia in neuropathic pain rats.
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A large number of experimental and clinical studies have confirmed that brief remifentanil exposure can enhance pain sensitivity presenting as opioid-induced hyperalgesia (OIH). N-methyl-D-aspartate (NMDA) receptor antagonists have been reported to inhibit morphine analgesic tolerance in many studies. Recently, we found that glycogen synthase kinase-3β (GSK-3β) modulated NMDA receptor trafficking in a rat model of remifentanil-induced postoperative hyperalgesia. ⋯ GSK-3β inhibitor TDZD-8 significantly attenuated remifentanil-induced mechanical and thermal hyperalgesia from 2 h to 48 h after infusion, and this was associated with reversal of up-regulated NR1 and NR2B subunits in both membrane fraction and total lysate. Furthermore, remifentanil incubation increased amplitude and frequency of NMDA receptor-induced current in dorsal horn neurons, which was prevented with the application of TDZD-8. These results suggest that inhibition of GSK-3β can significantly ameliorate remifentanil-induced hyperalgesia via modulating the expression and function of NMDA receptors, which present useful insights into the mechanistic action of GSK-3β inhibitor as potential anti-hyperalgesic agents for treating OIH.
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To study the potential of chemically modified tetracycline-3 (COL-3), a potent matrix metalloproteinase (MMP) inhibitor, to protect against the development of paclitaxel-induced painful neuropathy and its immunomodulatory effects. ⋯ Our results indicate that the MMP inhibitor COL-3 protected against paclitaxel-induced thermal hyperalgesia and, thus, could be useful in the prevention of chemotherapy-induced painful neuropathy.
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Cell transplantation · Jan 2013
Transplantation of human umbilical cord blood or amniotic epithelial stem cells alleviates mechanical allodynia after spinal cord injury in rats.
Stem cell therapy is a potential treatment for spinal cord injury (SCI), and a variety of different stem cell types have been grafted into humans suffering from spinal cord trauma or into animal models of spinal injury. Although several studies have reported functional motor improvement after transplantation of stem cells into injured spinal cord, the benefit of these cells for treating SCI-induced neuropathic pain is not clear. In this study, we investigated the therapeutic effect of transplanting human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) or amniotic epithelial stem cells (hAESCs) on SCI-induced mechanical allodynia (MA) and thermal hyperalgesia (TH) in T13 spinal cord hemisected rats. ⋯ Transplantation of hAESCs also significantly reduced the SCI-induced increase in NMDA receptor NR1 subunit phosphorylation (pNR1) expression in the spinal cord. Both hUCB-MSCs and hAESCs reduced the SCI-induced increase in spinal cord expression of the microglial marker, F4/80, but not the increased expression of GFAP or iNOS. Taken together, these findings demonstrate that the transplantation of hAESCs into the injured spinal cord can suppress mechanical allodynia, and this effect seems to be closely associated with the modulation of spinal cord microglia activity and NR1 phosphorylation.
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Peripheral or central nerve injury often leads to neuropathic pain. Although ketamine and pregabalin are first line options for the treatment of neuropathic pain, their clinical application is limited due to side effects such as sedation, dizziness and somnolence. We designed this study to determine whether the intrathecal (i.t.) co-treatment with ketamine and pregabalin at sub-effective low doses would elicit a sufficient pain relief without producing side effect in a neuropathic pain mouse model. ⋯ Interestingly, combined i.t. treatment groups (ketamine 3 µg+pregabalin 30 µg and ketamine 10 µg+pregabalin 30 µg) produced strong analgesia on neuropathic pain although these doses of ketamine and pregabalin alone are not effective. Moreover, rota rod test revealed that normal motor function was not affected by combined treatment while i.t. ketamine at doses above 10 µg showed a significant motor dysfunction. Results of this study suggested that i.t. co-treatment with ketamine and pregabalin at sub-effect low doses may be a useful therapeutic method for the treatment of neuropathic pain patients.