Visualization and quantification of the oxytocinergic pain and inflammation-related descending inhibitory pathways using transgenic rats

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K11039
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Orthopaedic surgery
• Research Institution: University of Occupational and Environmental Health, Japan
• Principal Investigator: Suzuki Hitoshi 産業医科大学, 医学部, 助教 (80644880)
• Co-Investigator(Kenkyū-buntansha): 上田 陽一 産業医科大学, 医学部, 教授 (10232745)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 神経障害性疼痛 / オキシトシン / 視床下部 / 脊髄後角 / 遺伝子改変動物

Outline of Final Research Achievements

We examined the Oxytocinergic system in the hypothalamo-neurohypophysial and hypothalamo-spinal pathway using a rat neuropathic pain model induced by partial sciatic nerve ligation (PSL). In the present study, we used transgenic rats expressing an oxytosin (OXT)-monomeric red fluorescent protein 1 (mRFP1) fusion gene.
In the PSL model, significant increase in the OXT-mRFP1 expression was observed in the posterior pituitary (PP), the supraoptic nucleus (SON), and paraventricular nucleus (PVN). In addition, significant increase of the mRNA levels of OXT and mRFP1 in the SON, and PVN were observed. Furthermore, OXT-mRFP1 granules with positive fluorescent reaction were remarkably increased in laminae I and II of the ipsilateral dorsal horn. These results suggest that neuropathic pain induced by PSL upregulates hypothalamic OXT synthesis and transportation to the OXTergic axon terminals in the PP and spinal cord.

Free Research Field

整形外科学

Academic Significance and Societal Importance of the Research Achievements

我々は神経障害性疼痛モデルラットにおけるオキシトシン(OXT)の発現動態を明らかにすることで、神経障害性疼痛によって内因性にOXTニューロンが活性化され疼痛の受容調節に深く関わっている事を明らかにした。今回の研究ではOXTが神経障害性疼痛などの慢性疼痛・難治性疼痛の病態に関与していることを明らかにし、今後治療のターゲットとなり得る示すことが出来た事で学術的にも社会的にも意義のある研究であったと言える。