The Research Of A Rat Model Of Post-herpetic Neuralgia Using Resting State Functional MRI

Purpose:To investigate the potential central nervous system of chronic pain and chronic pain transition in a rat model of post-herpetic neuralgia(PHN)at different time using functional connectivity method.Methods:A rat model of post-herpetic neuralgia was established by intraperitoneal injection of resintoxin(RTX).Changes in thermal pain threshold and mechanical pain threshold in a rat model of post-herpetic neuralgia was detected by painful behavioral experiments;Using resting state functional magnetic resonance imaging(rs-fMRI)functional connectivity(FC)method,taking the cingulate gyrus(Cg)as the region of interest,the time series of the brain regions of the region of interest were extracted,and correlation analysis based on voxel levels was performed with other brain regions of the whole brain.The constructed brain function connection map was performed by two-sample t test between groups(Alphasim correction,P<0.001,minimum voxel greater than 20)to form statistical results,and the brain function changes of the rat model group after postherpetic neuralgia were compared with those of the control group at 7 and 14 days,respectively.Results:The post-herpetic neuralgia rats had a reduced mechanical pain threshold and a higher thermal pain threshold,and stabilized at 14 days for at least 42 days.On the 7th day after RTX injection,we found that cingulate gyrus,sensory cortex,motor cortex,amygdala,striatum and cerebellum were enhanced.On the 14th day after RTX injection,in addition to the enhanced functional connection of the insular,sensory cortex,motor cortex,striatum and cerebellum,the hippocampus,nucleus accumbens and prefrontal cortex also showed enhanced functional connectivity.Conclusion:There is a functional connection abnormality between the cingulate gyrus and the brain regions such as feeling,emotion,learning and memory in a rat model of post-herpetic neuralgia,which Provides imaging evidence for understanding the pain sensation,mood regulation,and learning and memory mechanisms of post-herpetic neuralgia;The changes of brain function in rats with post-herpetic neuralgia are related to time,which provides an important theoretical basis for studying the cellular and molecular mechanisms of post-herpetic neuropathic pain.