The Comparative Research Of The Anti-RGCs-apoptosis Effect Of NGF Though Eyedrop And Intravitreal Injection With Ultrasound Microbubbles

ObjectiveComparison of the anti-apoptosis effect of mouse nerve growth factor(mNGF) with ultrasound microbubbles intravitreal delivery and eye drops through conjunctival sac administration on retinal ganglion cells(RGCs) of rabbit eyes. MethodsWe select intravitreal injection of 10 ?l 40 nM N-methyl-D-aspartate(NMDA) to make RGCs apoptosis model, transmission electron microscopy(TEM) observation to determine the apoptotic cells. 18 NewZealand rabbits were randomly divided into six groups. Following was the grouping: Control group(blank control), NMDA model group(intravitreal injection of 10 ?l NMDA), NMDA + mNGF eye drops group(intravitreal injection of 10 ?l NMDA, then proceed 180?g/ml mNGF eye drops), NMDA + mNGF simple intravitreal delivery group(intravitreal injection of 10 ?l NMDA+10 ?l 180?g/ml mNGF), NMDA + mNGF ultrasound microbubbles intravitreal delivery group(intravitreal injection of 10 ?l NMDA+10 ?l 180?g/ml mNGF+10?l microbubbles, then proceed ultrasonic irradiation), simple ultrasound microbubbles delivery group(intravitreal injection of 10?l microbubbles, then proceed ultrasonic irradiation). After 12 h, rabbits' eye cup was collected, sections was done 3 mm above, below, nasal and temporal to the optic disk. Retinal changes of each layer were observed by HE staining; RGCs apoptosis was evaluated by TUNEL, calculated as apoptosis index AI(%). Results 1.10 ?l 40 nM NMDA intravitreal injection in the 12 h observation can cause RGCs numbers reduced and increase TUNEL positive cells in rabbit eyes. RGCs apoptosis was found under TEM. 2. In RGCs numbers observation under HE staining, ultrasound microbubbles intravitreal delivery group had more than that in eye drops group. There was no obvious difference between mNGF simple intravitreal delivery and delivery combined with ultrasound microbubbles in light microscope observation. No decrease of RGCs was observed in simple ultrasound microbubbles delivery group. 3. Apoptosis index was as follow respectively: Control group 6.52±2.64%, NMDA model group 32.38±3.96%, NMDA + mNGF eye drops group 29.12±3.64%, NMDA + mNGF simple intravitreal delivery group 26.38±3.45%, NMDA + mNGF ultrasound microbubbles intravitreal delivery group 23.06±3.28%, simple ultrasound microbubbles delivery group 6.56±2.46%. There was no statistically difference in apoptosis index among above, below, nasal and temporal area. Calculated as the whole index of AI, AI of NMDA + mNGF ultrasound microbubbles intravitreal delivery group was higher than that of NMDA + mNGF eye drops group. In Control group, occasional TUNEL positive cells were observed in retinal ganglion cell layer of New Zealand rabbit. In NMDA model group, number of TUNEL positive cells increased significantly, compared with the Control group there was statistically significant difference(P<0.05). The mean of AI of NMDA + mNGF eye drops group was relatively smaller than NMDA model group, but there was no statistically significant difference(P>0.05). AI of NMDA + mNGF ultrasound microbubbles intravitreal delivery group and NMDA + mNGF simple intravitreal delivery group was smaller than that of NMDA model group, there was also difference between these two groups. There was no statistically significant difference(P>0.05) between simple ultrasound microbubbles delivery group and the Control group. ConculsionEye drops through conjunctival sac administration of m NGF cannot play the protection role to RGCs apoptosis due to NMDA intravitreal injection after 12 h. As to simple intravitreal delivery, mNGF ultrasound microbubbles intravitreal delivery can better give play to the protective function of mNGF to retinal ganglion cells.