摘要Objective To explore the mechanism of neurotropism in peripheral nerve regeneration byassessing the bioactivity of regeneration microcircumstance on motoneurons. Methods The motor branch offemoral nerve to quadriceps was incised and the distal stump was sutured with one-end silicone chamber. Thenerve regeneration chamber fluids from distal motor nerve stumps ( motor branch of femoral nerve ) ( MD-NR-CF) was collected 7d post-operatively, and with the same method, nerve regeneration conditioned fluids fromdistal stumps nerve stumps ( saphenous nerve) ( SD-NRCF) was collected. The dissociated rat's motoneuronswere co-cultured with MD-NRCF, SD-NRCF, basic fibroblast growth factor (b-FGF) and serum-free mediumfor 72h respectively and then were photographed under phase-contrast microscope. The longest neurites and cell-body areas of motoneurons from each group were measured by cell image processing computer system. MTT col-orimetric assay was also used to measure cell activation. Results The cells of MD-NRCF group had signifi-cantly longer neurites than the other 3 groups, and their activation was also superior to those of the othergroups. Conclusion These results indicate that MD-NRCF has more significant neurite-promoting and neu-robiological effects on motoneuron than SD-NRCF and b-FGF.