Proximal and distal nerve injuries induce changes of endoneurial laminin-1 in the spinal nerve roots - A quantitative immunohistochemical assessment
|Original title:||Proximal and distal nerve injuries induce changes of endoneurial laminin-1 in the spinal nerve roots - A quantitative immunohistochemical assessment|
|Authors:||Marek David, Petr Dubový, Ivana Hradilová Svíženská, Ilona Klusáková|
|Field:||Neurology, neurosurgery, neurosciences|
|WWW:||web stránky konference|
|Keywords:||behavioral tests; bilateral reaction of spinal nerve roots; dorsal root; endoneurial laminin-1; neuropathic pain; peripheral nervous system; proximal and distal injuries of sciatic nerve; ventral root|
Events in the spinal nerve roots after distal peripheral nerve injury, which induces neuropathic pain, are little characterized. Our previous results from immunofluorescence (IF) microscopy and computer-assisted image analysis revealed endoneurial extracellular matrix remodulation following dorsal and ventral rhizotomy. Therefore, we performed a quantitative immunohistochemical analysis to detect changes of laminin-1 (lam-1) in the ipsi- and contralateral spinal nerve roots of two neuropathic pain models - sciatic (ScNL) and spinal nerve (SNL) ligature. Behavioral tests demonstrated neuropathic pain induction (mechanical allodynia and thermal hyperalgesia) in ipsilateral hind paws of all experimental animals. A higher IF intensity of lam-1 was found in the ventral compared to dorsal roots of naive rats. In contrast to naive rats, significant bilateral enhancement of lam-1 IF was detected in the dorsal and ventral roots 1 to 3 days after ScNL as well as 1 to 7 days after SNL. Endoneurial lam-1 IF intensity in both ipsi- and contralateral spinal nerve roots was decreased 7 days following ScNL and 14 days from SNL. The decreased lam-1 IF intensity in the endoneurium of spinal nerve roots was to the level of IF brightness measured in naive animals. Even if endoneurial lam-1 IF changes are more distinct on ipsi- than contralateral side, their patterns in contralateral spinal nerve roots coincided with ipsilateral ones after both types of unilateral nerve ligature. Generally, lam-1 IF changes are larger in ScNL than SNL model of neuropathic pain. In conclusion, both proximal and distal nerve injuries lead to remodulation of the endoneurial lam-1 in the spinal nerve roots.