Experimental Study On Transferring PEGFP Into Mice Facial Nerve By Ultrasound-mediated Microbubbles

Objective: To investgate the feasibility and efficacy of transferring pEGFP into mice facial nerve by ultrasound-mediated microbubbles.Methods: Exposure, clamp bilateral facial nerve trunks to perform the injury of the mice's facial nerve. Plasmid enhanced green fluorescent protein(pEGFP)was chose to reflect the efficacy of transfection.48 mice were randomly divided into six groups : surgery only group(A), lipofectamineTM2000+ pEGFP group(B),Ultrasound+ Microbubbles+ pEGFP group(C), Microbubbles+ pEGFP group(D), Ultrasound+ pEGFP group(E) and pEGFP only treatment group(F).The bilateral facial nerve trunks were harvested at 3rd day after treatment respectively. The expression of pEGFP in facial nerve trunks was examined by laser scanning confocal microscope(LSCM) and western blot. Meanwhile, green florescent was observed in the mice's brainstem by LSCM.Results: The expression of pEGFP was the strongest in C(Ultrasound+ Microbubbles+ pEGFP group), followed by B (lipofectamineTM2000+ pEGFP group), E (Ultrasound+ pEGFP group), D (Microbubbles+ pEGFP group), F (pEGFP only treatment group) and A (surgery only group). The differences between C group and any other groups were statistically significant (P<0.05 or P<0.01). But pEGFP had not been detected in the mice's brainstem yet.Conclusion: On the one hand, the results indicated that the microbubbles could adsorb target gene plasmids and carried target gene into injured facial nerve effectively under the ultrasonic cavitation of a certain intensity and frequency ultrasound. On the other hand, it indicated that the ultrasonic cavitation, gene transfection and expression do not constitute a deadly type of damage to the injured facial nerve. Ultrasound-mediated microbubble destruction could improve the transfection of pEFGP in injury facial nerve trunks safely.