| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥300,000)
Fiscal Year 2007: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2006: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2005: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Experiments with post-operative pain
Male Sprague-Dawley rats (250g) were used in all experiments. An incision was made on the plantar aspect of the hind paw. Mechanical hypersensitivity was measured by determining the withdrawal threshold to von Frey filaments applied to the paw. Intraperitoneral administration of selective microglial inhibitor minocycline (50 mg/kg/day for 3 d) did not inhibit mechanical hypersensitivity. 0X42 expression in the spinal cord, however, suppressed 3d after minocycline injection. Intretherecal administration of p38MAPK inhibitor SB203580 (10 μg/day for 3d) also did not inhibit mechanical hypersensitivity. In the spinal cord, p-p38MAPK expressions were colocalized in 0X42 positive cells. This means p38MAPK is only expressed in microglia. In contrast, same paradigm injection with minocycline and SB203580 inhibited mechanical allodynia in rats with neuropathic pain induced by L5 spinal nerve transection (SNT). We concluded that microglia in the spinal cord does not have important role in the post-operative pain.
Experiments with neuropathic pain All animals used in this study were male Sprague-Dawely rats (160-180g). We used L5 spinal nerve transection (SNT) model with the some modification of spinal nerve ligation model described by Kim and Chung (1992). Selective glia cell inhibitor propentofylline was infused trathecally for 7 days by an osmotic infusion pump (1 μ1/h, 7 day pump, ALZET, Cupertino, CA) initiated just after, 14 d after, or 60 days after SNT. Intrathecal infusion of propentofylline started just after SNT suppressed the development of allodynia dose-dependently (0.1, 1 and 10 μg/day). Other two paradigms did not inhibit existing allodynia. In the spinal cord, expression of astrocytes (GFAP) was always suppressed after propentofylline infusion. We concluded that astrocytes in the spinal cord play an important role in development of neuropathic pain.
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