Effects Of Epidural Spinal Cord Stimulation On Expression Of5-HT_2A Receptor In The L3～4Spinal Cord After Spinal Cord Injury In Rats

Objective: The purpose of this study is to explore the effects of epidural spinal cordstimulation on expression of5-HT2Areceptor in the L3～4spinal cord after spinalcord injury in rats. To investigate the mechanism of ESCS improving locomotionfunction after SCI.Methods: Twenty adult male Sprague-Dawley rats were assigined randomly to one offive groups（:1） normal control group;（2）spinal cord injury group（3） spinal cordinjury plus treadmill training group (ST);(4) spinal cord injury plus treadmilltraining and ESCS group(TE);(5) spinal cord injury plus treadmill training plusESCS and Quipazine group(EQ). As to normal control group,we did not take anyintervention, while SI、ST、TE and EQ group rats received a T8spinal cordcomlplete transections surgery. Four weeks after the surgery, TE and EQ group ratsreceived an electrode implantation procedure, with the electrode field covering spinalcord segments L2. Four weeks after T8spinal cord comlplete transections surgery, theST rats received7cm/s treadmill training for20minutes per day. TE rats receivedESCS(50HZ、0.2ms) while carrying out treadmill training,20minutes per day.AS toEQ group, Quipazine was fistly given intraperitoneally20minutes before training,inthis group rats received ESCS(50HZ、0.2ms) during treadmill training training.All procedures in these ST、TE、EQ groups lasted for four weeks. After four weeksintervention, tissues of L3～L4spinal cord were cut off following standard protocolsfor RT-PCR. BBB scale score was performed both before surgery and every otherweek after surgery.Results:1、BBB scale score Five weeks after surgery, EQ group animals BBBscore was higher than SI，there were significant differences between them（P﹤0.05）.Six weeks after surgery, ST、TE group animals BBB score was higher than SI group，there were significant differences between them（P﹤0.05）.After eight weeks ofsurgery, the EQ group animals BBB score was higher than SI、ST and TE，there weresignificant differences between EQ group and other three groups（P﹤0.05）.The TEand ST groups BBB score was higher than SI group, when TE、ST groups comparedwith the SI group there were significant differences（P﹤0.05）。The TE group BBBscore was higher than ST group,but there were no significant differences between thethem（P﹥0.05）.2、Real-time quantitative RT-PCR Compared with the normal controlgroups, the expression of5-HT2Areceptor in the L3～4spinal cord of SI groupsbecome higher, there were no significant differences（P﹥0.05）.ST、TE、EQ groupwas lower than SI and NC group. When TE and EQ group compared with the SI、NCgroup,there were great significant difference（sP﹤0.05）.When ST compared with NCgroup there were no differences. When ST group compared with the SI group, thesignificant differences between ST and SI did not show out. The expression of5-HT2Areceptor in the L3～4spinal cord TE group was lower than ST group,TE waslower than EQ group.there were great significant differences between them（P﹤0.05）.Conclusion:1、ESCS may improves stepping ability after SCI, which may be partlymediated via5-HT2Areceptors.2、ESCS and Quipazine may have a cooperatively effect on stimulationthe expression of5-HT2Areceptors RNA in the L3～4spinal cord after spinal cord injury in rats，they can reduce the5-HT2Areceptor mRNA in the L3-4spinal cord.3、5-HT2Areceptor mRNA level in the L3-4decreases after chronic spinalcord injury, which can be beneficial to locomotion rehabilitation.