microRNA changes in the dorsal horn of the spinal cord of rats with chronic constriction injury: A TaqMan® Low Density Array study

Abstract

Elucidation of the mechanisms underlying neuropathic pain is expected to aid in the discovery and selection of effective therapeutic methods. Currently, microRNA (miRNA) is thought to play an important role in the development and maintenance of the nervous system. We, therefore, hypothesized that miRNAs are involved in neuropathic pain, and investigated this possibility by analyzing miRNA expression in the dorsal horn of the spinal cord in a chronic constriction injury (CCI) rat model using the TaqMan® Low Density Array (TLDA). Neuropathic pain model rats were produced by CCI induced by ligation of the sciatic nerve. The miRNA expression in the dorsal horn of the spinal cord was analyzed in Day 0 rats, with no sciatic nerve ligation or sham operation, Day 7 rats, examined 7 days after sciatic nerve ligation or sham operation, and Day 14 rats, examined 14 days after sciatic nerve ligation or sham operation using TLDA. In this study, 111 miRNAs were significantly regulated in CCI rats in both the Day 7 and Day 14 groups compared with sham rats in both groups. Of these 111, there were 75 miRNAs (67.6%) that had been analyzed in previous reports and 36 miRNAs (32.4%) related to the development of tumors of the nervous system and neurodegenerative diseases. Certain miRNAs were reported to be related to neuropathic pain; miR-500, -221 and -21. The expression levels of a large number of miRNAs in the dorsal horn of the spinal cord in CCI rats changed. These results provide a step toward elucidation of the mechanisms underlying neuropathic pain.

Time-specific microRNA changes during spinal motoneuron degeneration in adult rats following unilateral brachial plexus root avulsion: ipsilateral vs. contralateral changes

“…This result is consistent with the study by Bin Yu et al, who showed that miR-21 and miR-221 were upregulated in the dorsal root ganglia after resection of the sciatic nerve in rats [30]. The study by Yuuki Genda et al also revealed that certain miRNAs, including miR-500, -221 and -21, were related to neuropathic pain in a chronic constriction injury rat model [31]. …”

An approach to identify microRNAs involved in neuropathic pain following a peripheral nerve injury

“…Peripheral nerve injury not only produces changes in miR expression at the DRG, but also at the spinal cord (Genda et al, 2013) and brain (Arai et al, 2013; Hori et al, 2013). Hence, pain relevant miRs at any sensory level would potentially provide additional tools for the treatment of chronic neuropathic pain.…”

Practical Considerations of Convection Enhanced Delivery for Novel Therapies Treating Spinal Cord Injury Related Neuropathic Pain

“…In spinal nerve ligated rats, upregulation of miR-195 contributed to lip polysaccharide-induced expression of pro-inflammatory cytokines IL-1β, TNF-α, and iNOS in cultured microglia [78].Upregulation of miR-195 resulted in increased mechanical and cold hypersensitivity after PNI, whereas miR-195 inhibition reduced mechanical and cold sensitivity. Out of 111 miRNAs, 68% reported earlier and 32% related to the development of tumors of the nervous system and neurodegenerative diseases, few miRNAs, including miR-500, miR-221 and miR-21, relate to CCI-induced NP [79]. In another study miR-134, expression level found inversely related to MOR, the main transcript of μ-opioid receptor (MOR) gene expression [75].…”