Lentiviral vector-mediated expression of C3 transferase attenuates retinal ischemia and reperfusion injury in rats

Aims: Our previous study showed that intravitreal delivery of self-complementary AAV2 (scAAV2)-mediated exoenzyme C3 transferase (C3) can attenuate retinal ischemia/reperfusion (I/R) injury. The current study investigated the neuroprotective effects of lentivirus (LV)-mediated C3 transgene expression on rat retinal I/R injury. Main methods: The LV encoding C3 and green fluorescent protein (GFP) together (LV-C3-GFP) or GFP only (LV-GFP) was intravitreally injected to SPRAGUE-DAWLEY rats. On day 5 post-intravitreal injection, eyes were evaluated by slit-lamp examination. The GFP expression on retina was confirmed by in vivo and ex vivo assessments. RhoA GTPase expression in retina was examined by western blot. Retinal I/R injury was generated by transiently increasing intraocular pressure (110 mmHg, 90 min). Eyes were then enucleated, and retinas processed for morphological analysis and TdT-dUTP terminal nick-end labeling (TUNEL) assay. Key findings: No obvious inflammatory reactions or surgical complications were observed after intravitreal injection of LV vectors. There was a significant decrease of total RhoA GTPase level in the retina treated with LV-C3-GFP. Compared to the blank control group, LV-C3-GFP and LV-GFP did not affect the retinal thickness, cell density in ganglion cell layer (GCL), or numbers of apoptotic cells in retinal flat-mounts. In the LV-GFP-treated retinas, I/R decreased the retinal thickness and GCL cell density and increased apoptotic retinal cell numbers. LV-C3-GFP significantly protected against all these degenerative effects of I/R. Significance: This study indicated that LV-mediated C3 transgene expression exhibits neuroprotective effects on the retinal I/R injury and holds potential as a novel neuroprotective approach targeting certain retinopathies.