Preparation of PLLA/bpV(pic) microspheres and their effect on nerve cells

In this study, we prepared PLLA/bpV(pic) microspheres, a bpV(pic) controlled release system and examined their ability to protect nerve cells and promote axonal growth. PLLA microspheres were prepared by employing the o/w single emulsification-evaporation technique. Neural stem cells and dorsal root ganglia were divided into 3 groups in terms of the treatment they received: a routine medium group (cultured in DMEM), a PLLA microsphere group (DMEM containing PLLA microspheres alone) and a PLLA/bpV(pic) group [DMEM containing PLLA/bpV(pic) microspheres]. The effects of PLLA/bpV(pic) microspheres were evaluated by the live-dead test and measurement of axonal length. Our results showed that PLLA/bpV(pic) granulation rate was (88.2±5.6)%; particle size was (16.8±3.1)%, drug loading was (4.05±0.3)%; encapsulation efficiency was (48.5±1.8)%. The release time lasted for 30 days. In PLLA/bpV(pic) microsphere group, the cell survival rate was (95.2 ±4.77)%, and the length of dorsal root ganglion (DRG) was 718±95 μm, which were all significantly greater than those in ordinary routine medium group and PLLA microsphere group. This preliminary test results showed the PLLA/bpV(pic) microspheres were successfully prepared and they could promote the survival and growth of neural cells in DRG.