Molecular Pain (Apr 2010)

Inflammation and nerve injury induce expression of pancreatitis-associated protein-II in primary sensory neurons

  • Bao Lan,
  • Wang Qiong,
  • Zhang Fang-Xiong,
  • Yao Jun-Ru,
  • He Shao-Qiu,
  • Zhang Xu

DOI
https://doi.org/10.1186/1744-8069-6-23
Journal volume & issue
Vol. 6, no. 1
p. 23

Abstract

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Abstract Pancreatitis-associated protein (PAP)-I and -II, lectin-related secretory proteins, are members of the regenerating gene (Reg) family. Although expression of PAP-I was found in the dorsal root ganglion (DRG) neurons following peripheral nerve injury and cystitis, whether PAP-II could be expressed in DRG neurons in chronic pain models remains unclear. The present study shows an inflammation- and nerve injury-triggered expression of PAP-II in rat DRG neurons. In situ hybridization showed that only a few DRG neurons normally contained PAP-I and -II mRNAs. After peripheral inflammation, PAP-I and -II mRNAs were present in over half of small DRG neurons. Such an elevated expression of PAP-I and -II reached the peak level on the second day. Immunostaining showed that the expression of PAP-II was mostly increased in the isolectin B4-positive subset of small DRG neurons after inflammation. Furthermore, the expression of PAP-II was also induced in DRG neurons after peripheral nerve injury. Interestingly, PAP-II expression was shifted from small neurons on day 2 to large DRG neurons that expressed neuropeptide Y during the later post-injury days. These results suggest that PAP-II may play potential roles in the modulation of spinal sensory pathways in pathological pain states.