100 Section - Association between Symptoms of Depression and Neurogenesis in Fibromyalgia Model Mice

Tuesday, May 19, 2026

6:00 PM - 7:30 PM PT

Presenting Author/Autor expositor(s)

KM

Kenichiro Miyahara, PhD

Lecturer
Hokuriku University
Kanazawa, Ishikawa, Japan

Co-Author/Coautor(s)

YK

Yuji Kanazawa, PhD

Associate Professor
Hokkuriku University
Kanazawa, Ishikawa, Japan
TO

Takako Ohno-Shosaku, PhD

Professor
Hokuriku University
Kanazawa, Ishikawa, Japan
KI

Koji Ishikuro, PhD

Chief
Toyama University Hospital
Toyama, Toyama, Japan
HN

Hisao Nishijo, PhD

Professor
University of East Asia
Shimonoseki, Yamaguchi, Japan

Objectives : Fibromyalgia (FM) is primarily characterized by widespread pain. FM presents with a wide range of accompanying symptoms, including psychiatric symptoms such as depression. However, the cause of FM remains unknown, and no definitive treatment is available. Therefore, the pathophysiological mechanisms of FM must be identified for establishing a foundation for developing approaches for treating FM. We aimed to identify the pathophysiological mechanisms underlying depressive symptoms in patients with FM. We investigated the relationship between depressive symptoms and neurogenesis in an animal model of FM.

Design: Male C57BL/6J mice were administered reserpine three times daily to establish an FM model (RES group). The control group received vehicle solution injections under the same conditions (VEH group). BrdU, a marker of neurogenesis, was administered daily for six days starting on day 5 after the first injection. The forced swim test was performed to evaluate depressive symptoms on day 11. After the forced swim test, the brains were collected, and BrdU-positive cells in the hippocampal dentate gyrus were observed.

Results: The immobility time of the RES group tended to be longer in the forced swim test, suggesting depressive symptoms. The immunohistochemical analysis revealed that the BrdU-positive cell numbers in the hippocampal dentate gyrus tended to be higher in the RES group. A positive correlation was found between the immobility time and BrdU-positive cell number, suggesting an association between depressive behavior and enhanced neurogenesis.

Conclusion: Our results contrast those of previous studies that found reduced neurogenesis in FM model rats. This discrepancy in results may stem from the differences in the timing of observation following reserpine administration. We administered BrdU when the pharmacological effects of reserpine waned. Our findings collectively suggest that neurogenesis in the hippocampal dentate gyrus changes over time in the FM model and plays a role in the pathophysiology of FM-associated depressive symptoms.