[Protection of spinal motorneurons of section sciatic nerve by transplantation of NT-4 genetically expression cells into the side of section].

The NT-4 genetically engineered cells were made by infecting L-6TG cell (a rat myoblast cell line) in vitro with a retroviral vector pN2A containing the rat NT-4 cDNA. The bioactivities were determined by bioassay of PC12 cell survival rate. The rat with left sciatic nerve transaction was used as a model for treatment by implanting NT-4 genetically modified cell. The condition of motorneurons was assessed by Nissl stain and ChE stain. The results showed that: (1) the percentage of surviving Nissl-stained neurons on the lessened side of NT-4 (+) grafts significantly increased as compared to that with NT-4 (-) grafts 2-3 weeks and 3 months after sciatic nerve transaction, and (2) the grafted cells produced significant increase in the positive ChE stained area after sciatic nerve transaction in 1-3 weeks. Our observations indicate that adult motor neurons are still able to respond to neurotrophic factors and they may require the factors for survival.