Effects Of Ciliary Neurotrophic Factor Mediated By Ultrasound Microbubbles Intraocular Transfer After Optic Nerve Injury In Rat

BackgroundThe key premise of genetic research and treatment is to select the desired gene vector, ultrasound microbubbles as a new type of gene vector can safe, fast and effectively enhance the gene transfection and expression by reversibility increasing the permeability of cells.ObjectiveThis study was to observe the effects of ciliary neurotrophic factor (CNTF) gene mediated by ultrasound microbubbles intraocular transfer on visual function and retinal ganglion cell (RGCs) after optic nerve injury.MethodsFifty-five adult Sprague-Dawley (SD) rats were divided into 6 groups randomly, including normal control group(n=5), sham injury group(n=10), simple injury group(n=10), naked plasmid group(n=10), plasmid +ultrasonic irradiation group (n=10) and ultrasound microbubbles group (n=10). The model of optic nerve injury was made by forceps clip on the right optic nerve, and the corresponding intervene was performed in different groups. Flash visual evoked potential (F-VEP) was recorded in all rats before injury and 7 days after injury to evaluate the change of visual function, and survival of RGCs of rats was assessed by retrogradely label of FluoroGold (FG). Expression of CNTF mRNA in rat retina was determined by real time-PCR.ResultsLatency of F-VEP P1 wave in naked plasmid group, plasmid+ultrasonic irradiation group and ultrasound microbubbles group were shorter than simple injury group, and that of ultrasound microbubbles group were shorter than naked plasmid group and plasmid+ultrasonic irradiation group, showing significant difference among them(P<0.05). The amplitude of P1 wave in naked plasmid group, plasmid +ultrasonic irradiation group and ultrasound microbubbles group were elevated in comparison with simple injury group, and that of ultrasound microbubbles group was higher than naked plasmid group and plasmid+ultrasonic irradiation group (P<0.05). Significant difference in P1 amplitude was also seen between ultrasound microbubbles group and control group(P<0.05). The RGCs in simple injury group was least among various groups(P<0.05). In ultrasound microbubbles group, the RGCs were more than naked plasmid group and plasmid +ultrasonic irradiation group, but less than control group and sham injury group (P<0.05). RT-PCR revealed that the relative expression values of CNTF mRNA in ultrasound microbubbles group were higher than those of control group, sham injury group, simple injury group, naked plasmid group and plasmid +ultrasonic irradiation group with the statistically significant difference among them (P<0.05).ConclusionUnder irradiation of low-frequency ultrasound wave, ultrasound-mediated microbubbles destruction can increase intraocular transfection and expression of CNTF gene and promote the recovery of visual function.