Articles: hyperalgesia-pathology.
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The activation of spinal cord microglia and astrocytes after peripheral nerve injury or inflammation contributes to behavioral hypersensitivity. The contribution of spinal cord glia to mechanical hypersensitivity after hind paw incision has not been investigated previously. Male Sprague-Dawley rats underwent a unilateral plantar hind paw incision, and the development of mechanical hypersensitivity was assessed by using von Frey filaments. The activation of spinal cord microglia and astrocytes was measured 1, 2, 3, and 5 days after hind paw incision by using immunohistochemistry. The glial activation inhibitor, fluorocitrate, was administered intrathecally 24 hours after hind paw incision to determine glial involvement in mechanical hypersensitivity. Hind paw incision induced an activation of spinal astrocytes ipsilateral to incision within 24 hours. Both microglia and astrocytes reached a maximum activation 3 days after hind paw incision. Fluorocitrate produced a dose-dependent reduction in mechanical hypersensitivity when administered 24 hours after hind paw incision. Spinal cord glial activation contributes to the mechanical hypersensitivity that develops after hind paw incision. ⋯ Hind paw incision produces mechanical hypersensitivity that can be alleviated with the inhibition of spinal cord glia. Our results suggest that the activation of spinal cord astrocytes within 24 hours of incision contributes to mechanical hypersensitivity. Therefore, spinal cord astrocytes might represent a novel target for the treatment of postoperative pain.
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Fertility and sterility · Nov 2006
Clinical TrialPain, mast cells, and nerves in peritoneal, ovarian, and deep infiltrating endometriosis.
To detect and quantify mast cells in peritoneal, ovarian, and deep infiltrating endometriosis and to study the relationship between mast cells and nerves in endometriosis. ⋯ The presence of increased activated and degranulating mast cells in deeply infiltrating endometriosis, which are the most painful lesions, and the close histological relationship between mast cells and nerves strongly suggest that mast cells could contribute to the development of pain and hyperalgesia in endometriosis, possibly by a direct effect on nerve structures.
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Osteoarthr. Cartil. · Oct 2006
Surgically induced osteoarthritis in the rat results in the development of both osteoarthritis-like joint pain and secondary hyperalgesia.
In the present study, we sought to develop/characterize the pain profile of a rat model of surgically induced osteoarthritis (OA). ⋯ The rat medial meniscal tear (MMT) model mimics both nociceptive and neuropathic OA pain and is responsive to both a selective cylooxygenase-2 (COX-2) inhibitor commonly utilized for OA pain (rofecoxib) and a widely prescribed drug for neuropathic pain (gabapentin). The rat MMT model may therefore represent a predictive tool for the development of pharmacologic interventions for the treatment of the symptoms associated with OA.
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Hyperbaric oxygen therapy has been used to treat a variety of ailments from carbon monoxide poisoning to fibromyalgia. The purpose of this experiment was to explore the effect of hyperbaric oxygen treatment on carrageenan-induced inflammation and pain in rats. Hyperbaric oxygen treatment significantly decreased inflammation and pain following carrageenan injection. Clinically hyperbaric oxygen may be used in situations where NSAIDS are contraindicated or in persistent cases of inflammation.
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Chemical cauterization of the central cornea with silver nitrate was assessed as a superficial injury model of tissue sensitization accompanying acute inflammation. Adult male Sprague-Dawley rats were anesthetized with halothane gas, and the centers of their right corneas treated with a silver nitrate applicator stick (75% silver nitrate, 25% potassium nitrate) to produce a discrete lesion 1 mm in diameter. Edema of the corneal stroma and elevated immune cell counts became significant 4 h after cauterization, and were still evident after 48 h. ⋯ A significant increase in stimulus-induced blinking was evident 2 h after cauterization. Chemical sensitization peaked at 6 h, and was no longer significant at 12 h. We conclude that silver nitrate cauterization produces acute corneal inflammation and hyperalgesia, and may prove a useful model for the study of primary afferent nociceptors.