OBJECTIVETo study the preparative method of controlled release microspheres incorporating basic fibroblast growth factor (bFGF) and the bioactivities of bFGF, which were released from bFGF microspheres, on the cultured Schwann cells.

METHODSbFGF was microcapsulated with the multiple emulsion encapsulative method using polylactic-co-glycolic acid (PLGA) as coating material. Its morphology, particle size distribution, drug loading, enveloping rate and in vitro release property were studied. The cultured Schwann cells were grouped according to the different ingredients being added to the culture medium of bFGF group or bFGF-PLGA group. Then the cytometry, cytoactivity detection and mitotic cycle analysis of Schwann cells were performed.

RESULTSThe morphology and the particle size distribution of the bFGF-PLGA microspheres were even and good. The drug loading and enveloping rate of microspheres were (27.18 x 10(-3))%+/-(0.51 x 10(-3))% and 66.43%+/-1.24%. The release property of microspheres in vitro was good and the overall release rate was 72.47% in 11 days. The in vitro cellular study showed that: at the first 2 days of plate culture, the cell number and viability of the bFGF group were statistically higher than the bFGF-PLGA group; at the 3rd and 4th days of plate culture, the cell number and viability of bFGF and bFGF-PLGA groups showed no difference; at the 6th and 8th days of the plate culture, the cell number and viability of the bFGF-PLGA group were statistically higher than the bFGF group. By flow cytometry examination, at the 2nd day of plate culture, the G2/M+S percentage of bFGF group was statistically higher than the bFGF-PLGA group, at the 4th and 8th days of plate culture, the G2/M+S percentage of the bFGF-PLGA group was statistically higher than the bFGF group.

CONCLUSIONSIt is practical to prepare the bFGF-PLGA microspheres with the multiple emulsion encapsulative method. bFGF-PLGA microspheres can preserve the bioactivities of bFGF effectively and promote the proliferation of Schwann cells in a long period because of the controlled release of bFGF from the microspheres.