Reelin Expression Of Spinal Cord On Neuropathic Pain Induced By Chronic Constriction Of The Sciatic Nerve Ganglion In The Rat

ObjectiveTo observe the expression of Reelin in the lumbar spinal cord in a ratmodel of chronic constriction injury on sciatic nerve.MethodsOne hundred and thirty-two adult (250-350g) male Sprague-Dawleyrats were divided into two groups including Sham group（n=48）and CCIgroup（n=84）, chronic constriction injury was made by ligating the rightsciatic nerve in the rats of CCI group, Sham operation was performed on therats of Sham group whose sciatic nerve were just expsured without ligation.All the rats received behavioral observation and tests，paw withdrawalmechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL)were performed one day before and1,4,7,10,14,21,28days post operation.We analyzed Reelin mRNA and Reelin levels on lumbar spinal dorsal cordsrespectively through RT-PCR and western-blot experiments.Results1. There is no significantly difference for PWMT and PWTL among therats before surgery. For Sham group, there is no obvious change on PWMTand PWTL during the whole period. Compared with Sham group, bothPWMT (P <0.01) and PWTL (P <0.01) were significantly decreased afterCCI surgery on the right side.2. Compared with Sham group, Reelin mRNA expression decreasedstarting from postoperative day4, and reduced to the lowest level aroundpostoperative day10, then was keeping the lower level until28days afterCCI operation. Correlation analysis showed, positive correlation betweenReelin mRNA and PWMT（rp=0.795，P <0.05）, and significantly positivecorrelation between Reelin mRNA and PWTL（rp=0.845，P <0.01）3. Contrast to Sham group, Reelin expression began decreasing from postoperative day4, then was going down until28days after CCI operation.Correlation analysis indicated, Reelin expression was positively related withPWMT（rs=0.746，P <0.05）, and also positively related with PWTL（rp=0.819，P <0.05）ConclusionsReelin expression in spinal cord is downregulated following chronicconstriction of the sciatic nerve ganglion in the rat, and the change ispositively related to pain severity. This indicates that Reelin may play a rolein pain processing induced by chronic constriction injury.