OBJECTIVETo investigate the feasibility of promoting nerve regeneration by using microcapsulated NGF-expressing cells transplantation.

METHODSThe plasmid pcDNA3. 1 + /NGF, containing rat NGF gene, was transfected into the NIH 3T3 cell by using FuGENE6 transfection reagent. The genetically modified cells expressing NGF gene were enclosed within the alginate-polylysine-alginate (APA) microcapsules and then cultured in vitro. The growth and NGF secretion of the cells were measured periodically. At the same time, these microcapsulated NGF-expressing cells were transplanted into the injured sciatic nerve. The regeneration and functional recovery of the nerve were evaluated in 4 weeks, 8 weeks and 12 weeks after the operation.

RESULTSThe microcapsulated cells had survived and secreted the NGF in three months in vitro. In the group with microcapsulated NGF-expressing cells, the number of the regenerated axons was in large and the nerve fibers were arranged regularly. Compared to other groups, there was less scar , edema and monocytes found at the stoma in the goup. The moter nerve conductive velocity, nerve muscle-action potential and SFI were improved.

CONCLUSIONSThe microcapsulated NGF-expressing cells could significantly enhance the nerve regeneration and reduce inflammatory response of xenograft.