Objective: To explore the effect of electroacupuncture (EA) combined with Schwann cell (SC) transplantation (SCT) on remyelination of axons and neuregulin (Nrg1) in rats with compressed spinal cord injury(CSCI),so as to explore the mechanism of EA and SCT underlying improvement of CSCI.
Methods: SD female rats were randomly divided into normal, mo-del, EA, SCT, and EA+ SCT groups (n=40 per group). A self-developed model of spinal compressed injury was adopted in this study. Rats of the model group were administrated laminectomy without treatment. Rats in the EA group were administrated EA stimulation at "Dazhui"(GV14), "Mingmen"(GV7), bilateral "Zusanli" (ST36) and "Taixi" (KI3) on the second day post-surgery for 10 min. Rats in the SC group were administrated SCT at 1 week post-surgery, and in the EA+SC group were given EA stimulation combined with SCT. The injured spinal cord tissue was obtained 0, 2, 4 and 8 weeks after compressed spinal injury. The functional recovery was assessed by Basso-Beattie-Bresnahan (BBB) score. The survivals and migration of SC after transplantation, myelination were observed by immunofluorescence. The ultrastructure of myelin in injured site was observed by transmission electron microscope，and the expression levels of glial fibrillary acidic protein (GFAP), protein zero(P0), and Nrg1 and Nrg1-ntf (cleavage protein of Nrg1) proteins of the spinal cord were detected by Western blot.
Results: Compared with the normal group, BBB scores in the model group was significantly decreased（P<0.05）,nervous fibers were demyelinated, numbers of normal and newborn myelination were decreased(P<0.05)，expression of P0 was significantly increased (P<0.05)，expression of GFAP was significantly increased(P<0.05)，and the expression levels of Nrg1 and Nrg1-ntf proteins were decreased(P<0.05). In comparison with the model group, the BBB scores in the EA, SCT and EA+SCT groups were significantly increased（P<0.05,P<0.01）, demyelination was improved, numbers of normal and newborn myelinations were increased(P<0.05,P<0.01)，expressions of P0 were significantly increased (P<0.05,P<0.01)，expressions of GFAP were significantly decreased(P<0.05)，and the expression levels of Nrg1 and Nrg1-ntf proteins were increased (P<0.05, P<0.01).The differences were most significant in the EA+SCT group among the three groups.
Conclusion: EA can improve the locomotor function in CSCI rats, which may be rela-ted to its functions in promoting the survival and migration of transplanted SC and remyelination, and increasing the expressions of Nrg1 and its cleavage protein after SC transplantation.
目的：观察电针联合雪旺氏细胞(SC)移植对脊髓压迫性损伤(CSCI) 后轴突再髓鞘化的作用以及神经调节蛋白（Nrg1）表达的影响，探讨电针联合SC移植对脊髓损伤的修复作用机制。方法：雌性SD大鼠随机分为正常组、模型组、电针组、单纯雪旺氏细胞移植组(简称移植组)、电针联合雪旺氏细胞移植组(简称联合组)，每组40只。采用自行研制的大鼠脊髓压迫器制备CSCI模型。电针组于造模成功次日电针“大椎”“命门”及双侧“足三里”“太溪”，10 min/d，最多干预8周；移植组于术后1周进行SC移植治疗；联合组给予电针及SC移植治疗。各组分别于造模后0、2、4、8周评定BBB评分后取材；免疫荧光法观察SC移植后的存活、迁移及髓鞘形成情况；电镜检测脊髓损伤节段髓鞘的超微结构；Western blot法检测Nrg1及其裂解物（Nrg1-ntf）、髓鞘蛋白(P0)、星形胶质细胞标记物(GFAP)的相对表达量。结果：与正常组比较，模型组BBB评分显著降低（P<0.05），神经纤维发生脱髓鞘病变，正常髓鞘、新生髓鞘数量显著降低（P<0.05），变性髓鞘数量显著增多（P<0.05），P0、GFAP表达显著升高（P<0.05），Nrg1、Nrg1-ntf表达显著降低（P<0.05）。与模型组比较，造模后2周联合组及造模后4、8周电针组、移植组、联合组BBB评分显著升高（P<0.05，P<0.01），3个治疗组脱髓鞘病变均改善，正常髓鞘、新生髓鞘数量显著升高（P<0.05，P<0.01），造模后2、4、8周电针组、联合组及造模后8周移植组P0表达显著升高（P<0.05，P<0.01），移植组造模后2周GFAP表达显著升高、造模后8周显著降低（P<0.05），造模后2、4、8周电针组、联合组GFAP表达显著降低（P<0.05），造模后2、4、8周电针组、联合组Nrg1表达显著升高（P<0.05，P<0.01），造模后4、8周电针组、联合组Nrg1-ntf表达显著升高（P<0.05）。与联合组比较，造模后8周电针组BBB评分显著降低（P<0.05）、电针组和移植组新生髓鞘数量显著降低（P<0.05），造模后2、4周移植组及造模后2、4、8周电针组P0表达显著降低（P<0.01,P<0.05）,造模后2、4、8周移植组GFAP表达显著升高（P<0.05），造模后4、8周电针组、移植组Nrg1、Nrg1-ntf表达降低（P<0.05）。结论：电针可能通过提高SC移植后脊髓组织内Nrg1及Nrg1-ntf的表达，提高SC的存活、迁移能力，减少星形胶质细胞数量，加强CSCI后再髓鞘化水平，促进CSCI后神经运动功能恢复。.
Keywords: Compressed spinal cord injury; Electroacupuncture; Locomotor function; Remyelination; Schwann cell transplantation.