Reactivation of Denervated Schwann Cells by Embryonic Spinal Cord Neurons to Promote Axon Regeneration and Remyelination

Figure 3

Axonal and myelin sheath status in the distal nerve stump after the 1^st and 2^nd surgery-I. Longitudinal sections of the distal part of the transplanted site were stained with NF200 (an axon marker) and MBP (a myelin sheath marker). (a–d) One month after the 1^st surgery, there were small amounts of myelin debris and axons in the distal stump in the vehicle group. Meanwhile, NF200-positive axons appeared in the cell group and were partially wrapped by the MBP-positive myelin sheath. (e–h) Three months and (i–l) six months after the 1^st surgery, the axonal and myelin debris had been gradually eliminated in the vehicle group, and abundant NF200-positive axons and MBP-positive myelin sheath were observed in the cell group. (m–p) Two weeks after the 2^nd surgery-I, the vehicle group showed no positive staining. Meanwhile, the distal stump in the cell group reentered a denervated status, exhibiting discontinuous axons and myelin sheath debris. (u) The normalized intensities were determined in triplicate in sections taken from 1 rat. The trend in the expression intensity of NF200-positive axons was consistent with the MBP-positive myelin sheath in both groups. A sharp decline was observed in the expression of both markers after cell excision in the cell group. Scale bar = 100 μm.