Upregulation of matrix metalloproteinase-9/2 in the wounded tissue, dorsal root ganglia, and spinal cord is involved in the development of postoperative pain.

Abstract

Emerging evidence implicates the upregulation of matrix metalloproteinase (MMP)-9/2 in the dorsal root ganglion (DRG) and spinal cord as a contributor to the pathogenesis of chronic pain. In the current study, the expression of MMP-9/2 in wounded tissue, ipsilateral DRG, and the spinal dorsal horn as well as its role in the development of postoperative pain were examined following plantar incision in rats. Our results showed that plantar incision resulted in increased expression of MMP-9/2 in wounded tissue and ipsilateral L4/5 DRGs. Although gelatin zymography detected an increased activity of MMP-9, only MMP-2 protein was increased in the spinal cord. Results of double immunofluorescence staining showed MMP-2 expression in DRG neurons and satellite glial cells, but MMP-9 was found only in neurons. In the spinal cord, MMP-2 was expressed in neurons and astrocytes, and MMP-9 was expressed in neurons and somewhat in microglial cells. Planter incision also elicited increased expression of p-Erk, p-p38, and IL-1β in wounded tissue, ipsilateral L4/5 DRGs, and dorsal horn. Prior intraplantar or intrathecal injection of MMP-9- and MMP-2-specific inhibitors partially prevented reductions of paw withdrawal threshold and paw withdrawal latency following plantar incision. The maturation of IL-1β was also inhibited by the treatment. Moreover, MMP-9 inhibition suppressed p38, and MMP-2 inhibitor reduced the Erk phosphorylation in wounded tissue, DRGs, and dorsal horn. Immunofluorescence staining detected colocalization of MMP-9 with p38 and MMP-2 with Erk in DRG and spinal cord. Together, the above results reveal that upregulated MMP-9 via p38/IL-1β and MMP-2 via Erk/IL-1β signaling in the wounded tissue, ipsilateral DRG, and dorsal horn contribute to the development of postoperative pain.

• Authors: Han-Wen Gu, Fei Xing, Ming-Jun Jiang, Yingjun Wang, Liying Bai, Jian Zhang, Tong-Tong Li, Wei Zhang, Ji-Tian Xu
• Journal: Brain research (Brain Res) Vol. 1718 Pg. 64-74 (09 01 2019) ISSN: 1872-6240 [Electronic] Netherlands
• PMID: 31075261 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2019 Elsevier B.V. All rights reserved.

Chemical References

• Interleukin-1beta
• p38 Mitogen-Activated Protein Kinases
• Matrix Metalloproteinase 2
• Mmp2 protein, rat
• Matrix Metalloproteinase 9
• Mmp9 protein, rat

Topics

• Animals
• Ganglia, Spinal (metabolism)
• Hyperalgesia (metabolism)
• Interleukin-1beta
• MAP Kinase Signaling System
• Male
• Matrix Metalloproteinase 2 (metabolism)
• Matrix Metalloproteinase 9 (metabolism)
• Microglia (metabolism)
• Neuroglia (metabolism)
• Pain Measurement
• Pain, Postoperative (metabolism)
• Rats
• Rats, Sprague-Dawley
• Signal Transduction
• Spinal Cord (metabolism)
• Spinal Cord Dorsal Horn (metabolism)
• Wound Healing (physiology)
• p38 Mitogen-Activated Protein Kinases (metabolism)