Alteration of MEK-ERK and NF-κB signal transduction pathway in spinal cord of rats with neuropathic pain / 临床麻醉学杂志

ABSTRACT

Objective To investigate the signaling pathways involved in the activation of neuron and glia in spinal cord in rats with neuropathic pain. Methods Twelve female SD rats (weighted 150 to 200 g) were randomized into two groups of spared nerve injury(group SNI) and control(group C). Surgery was performed to build model of SNI neuropathic pain in group SNI. Foot-lift response frequency to mechanical stimulation for ipsilateral hindpaw was assessed by 12 g and 2 g touch stimulator at different times. On the 11~(th) day after operation, 3 rats from each group were fixed by perfusion and the expressions of mitogen-activated/extracellular signal-regulated kinase (MEK), p-mitogen-activated/extracellular signal-regulated kinase (p-MEK), p-extracellular regulated protein kinase(p-ERK) and nuclear factor kappa B (NF-κB) were detected by immunohistochemistry method. And proteins from ipsilateral LA-6 spinal cord in other 3 rats from each group were extracted for Western Blot analysis. Western Blot and immunohistochemistry were performed with antibodies specific for MEK, p-MEK, pERK and NF-κB. Results All rats in group SNI developed a relative unchangeable mechanical allodynia since the 5~(th) day after operation. The results of immunohistochemistry method showed that the expression of MEK was mainly in cytoplasm, p-MEK in cell nuclear, p-ERK in astrocyte and NF-κB in neuron according to morphologic observation. Western Blot analysis indicated that the expressions of p-MEK, p-ERK and NF-κB in group SNI were increased significantly compared with those in group C(P<0. 05). Conclusion In the spinal cord of rats with neuropathic pain, MEK-ERK signaling pathway is activated in astrocytes and NF-κB in neurons, which may contribute to the development of neuropathic pain.