Abstract
Purpose :
Recent data have shown that gut microbiome changes may play a role in age related macular degeneration (AMD). Gnotobiotic animal models and germ-free (GF) mice are considered the gold-standard experimental tools for examining host-microbe interactions. Laser induced choroidal neovascularization (CNV) is a widely used model for wet AMD and ocular angiogenesis research but currently, no germ-free animal models of CNV exist. The purpose of this study was to establish a sterile technique for laser- induced CNV in germ-free mice.
Methods :
Germ Free C57Bl/6 mice were bred and maintained in sterile flexible film isolators. Mice were provided sterile water, autoclaved diet, autoclaved pine shavings and Enviro-dri®nesting material. Sterility monitoring was achieved by weekly fecal cultivation throughout the experiment. We performed laser photocoagulation using an argon 532-nm laser (IRIDEX Oculight GLx, Mountain View, CA, USA) attached to a customised slit-lamp delivery system (Carl Zeiss 30SL-M, Jena, Germany).
Results :
Twelve-week old GF mouse was transferred to a surface sterilized laminal flow hood and was handled under sterile conditions by personnel with sterile gown and gloves and standard surgical face mask. Anesthesia was achieved via an intraperitoneal injection using sterile technique of a 22 micron filter sterilized cocktail of xylazine and ketamine. Pupils were dilated with sterile 1% tropicamide solution and kept hydrated with sterile artificial tears. To allow visualization of the retina, a sterile glass coverslip with a drop of sterile artificial tear solution was gently placed on the surface of the mouse eye. Mouse was placed on a customized mouse holder close to the edge of laminal flow hood. The laser system was placed outside of the laminal flow hood. Laser spots (50-μm spot size, 100-ms duration, 150-mW power) were delivered around the optic nerve using sterile technique. After the laser procedure, mouse was transferred to single sterile hermetically sealed ventilated cage on a ventilated rack and monitored for 2 weeks. Stool cultures remained sterile for up to 2 weeks after the laser procedure.
Conclusions :
To our knowledge, this is the first described germ-free murine model of laser-induced CNV. This approach is a powerful and valuable tool to study the host-microbial and gene interactions in wet-AMD and ocular angiogenesis research fields.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.