Effect of electroacupuncture combined with Schwann cell transplantation on remyelination of axons and neuregulin1 expression in rats with compressed spinal injury

Abstract

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. 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. 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. 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.