Resting-state fMRI analyses of a pain state transition induced by a chemokine signal-regulating agent in tumor model mice

Motivation: Chronic pain significantly interferes with daily life in cancer patients. However, the mechanisms of pain responses and neurotransmission circuits in the brain remain elusive. Goal(s): The aim is to develop a diagnostic MRI method to monitor the cancer pain state and the state transition induced by analgesic candidates. Approach: Tumor-bearing cancer pain model mice were monitored by resting-state fMRI, and the pharmacological effect was evaluated for a newly developed chemokine signal-regulating agent. Results: Pain-related brain regions were significantly identified in stronger functional connective networks, while functional connectivity was suppressed after administration of the chemokine signal-regulating agent. Impact: The pain state transition induced by the analgesic agent in the tumor-bearing mouse brain was characterized by resting-state fMRI. Our experimental system is useful for the evaluation of new analgesic candidates in nonclinical and, expectantly, clinical studies.