TY - JOUR
T1 - The antinociceptive effect of the asthma drug ibudilast in rat models of peripheral and central neuropathic pain
AU - Hama, Aldric T.
AU - Broadhead, Alex
AU - Lorrain, Daniel S.
AU - Sagen, Jacqueline
PY - 2012/2/10
Y1 - 2012/2/10
N2 - Ibudilast, an asthma drug, has demonstrated antinociceptive effects in several rat models of peripheral neuropathic pain, and a proposed mechanism of action is the inhibition of release of the cytokine tumor necrosis factor-α (TNF-α) from activated spinal microglia. Spinal glial activation has also been demonstrated in rat models of central neuropathic pain following spinal cord injury (SCI). The current study evaluated the effect of a short course of treatment with ibudilast on SCI-induced pain, and for comparison, following a chronic constriction injury (CCI; the Bennett model) of the sciatic nerve in rats. The effects of ibudilast treatment on spinal (SCI and CCI rats), and nerve tissue (CCI only) TNF-α content were also evaluated. Following an acute midthoracic SCI with a microvascular clip (20-g force), hindpaw withdrawal thresholds were significantly decreased, indicating below-level cutaneous tactile hypersensitivity. Likewise, unilateral loose ligation of the sciatic nerve led to a robust ipsilateral tactile hypersensitivity. Rats were treated with either ibudilast (10 mg/kg IP) or vehicle (2 mL/kg) during the period of robust and steady hindpaw hypersensitivity for each model-CCI rats were treated 14-16 days post-surgery, and SCI rats were treated 30-32 days post-surgery-and tested daily. Ibudilast ameliorated hindpaw hypersensitivity in both SCI and CCI rats, whereas vehicle treatment had no effect. Interestingly, repeated treatment led to increased baseline thresholds, beyond the duration of the drug half-life, suggesting persistent changes in neuropathic pain processing. In SCI rats, an increase in TNF-α content in spinal tissue rostral to the SCI was observed. Ibudilast treatment did not significantly alter this increase. In rats with a CCI, TNF-α content was markedly increased in the ipsilateral sciatic nerve and was partially reduced following ibudilast, but not vehicle, treatment. Ibudilast could be useful for the treatment of neuropathic pain of central as well as peripheral origin.
AB - Ibudilast, an asthma drug, has demonstrated antinociceptive effects in several rat models of peripheral neuropathic pain, and a proposed mechanism of action is the inhibition of release of the cytokine tumor necrosis factor-α (TNF-α) from activated spinal microglia. Spinal glial activation has also been demonstrated in rat models of central neuropathic pain following spinal cord injury (SCI). The current study evaluated the effect of a short course of treatment with ibudilast on SCI-induced pain, and for comparison, following a chronic constriction injury (CCI; the Bennett model) of the sciatic nerve in rats. The effects of ibudilast treatment on spinal (SCI and CCI rats), and nerve tissue (CCI only) TNF-α content were also evaluated. Following an acute midthoracic SCI with a microvascular clip (20-g force), hindpaw withdrawal thresholds were significantly decreased, indicating below-level cutaneous tactile hypersensitivity. Likewise, unilateral loose ligation of the sciatic nerve led to a robust ipsilateral tactile hypersensitivity. Rats were treated with either ibudilast (10 mg/kg IP) or vehicle (2 mL/kg) during the period of robust and steady hindpaw hypersensitivity for each model-CCI rats were treated 14-16 days post-surgery, and SCI rats were treated 30-32 days post-surgery-and tested daily. Ibudilast ameliorated hindpaw hypersensitivity in both SCI and CCI rats, whereas vehicle treatment had no effect. Interestingly, repeated treatment led to increased baseline thresholds, beyond the duration of the drug half-life, suggesting persistent changes in neuropathic pain processing. In SCI rats, an increase in TNF-α content in spinal tissue rostral to the SCI was observed. Ibudilast treatment did not significantly alter this increase. In rats with a CCI, TNF-α content was markedly increased in the ipsilateral sciatic nerve and was partially reduced following ibudilast, but not vehicle, treatment. Ibudilast could be useful for the treatment of neuropathic pain of central as well as peripheral origin.
KW - allodynia
KW - AV-411
KW - glia
KW - off-label use
KW - peripheral neuropathy
KW - spinal cord injury
KW - tumor necrosis factor-α
UR - http://www.scopus.com/inward/record.url?scp=84857306382&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84857306382&partnerID=8YFLogxK
U2 - 10.1089/neu.2011.1863
DO - 10.1089/neu.2011.1863
M3 - Article
C2 - 21806469
AN - SCOPUS:84857306382
VL - 29
SP - 600
EP - 610
JO - Journal of Neurotrauma
JF - Journal of Neurotrauma
SN - 0897-7151
IS - 3
ER -