The rat intervertebral disk degeneration pain model: relationships between biological and structural alterations and pain

Table 1 Altered gene expression in the sensory neurons in dorsal root ganglions in a neuropathic animal model compared to the traumatic disk injury-initiated chronic discogenic pain model

Tissues	Pain modulator	Neuropathic pain (sciatic nerve ligation)^a, reference	Disk degeneration back pain model^b, relative fold induction (n= 12) (P values)
Dorsal horn	Dynorphin	Upregulated [28]	1.941 ± 0.162 (P < 0.05)
	NK-1	Upregulated [29]	2.512 ± 0.521 (P < 0.05)
DRG	BDNF	Upregulated [23]	1.841 ± 0.312 (P < 0.05)
	NPY	Upregulated [24]	5.367 ± 0.474 (P < 0.05)
	CGRP	Downregulated [21]	0.487 ± 0.433 (P < 0.05)
	Substance P	Downregulated [22]	0.712 ± 0.251 (P < 0.05)
	Galanin	Upregulated [25]	1.1 ± 0.219 (equal)

BDNF = brain-derived neurotrophic factor; CGRP = calcitonin gene-related peptide; DRG = dorsal root ganglion; NK-1 = neurokinin 1; NPY = neuropeptide Y. ^aUpregulated and downregulated expression patterns are relative to sham controls. ^b25-gauge drilling was performed in 12 mice; data are means ± SEM.

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