Introducing a Porcine Inflammatory Ex Vivo Retina Model for Diabetic Retinopathy

This study aimed to develop an ex vivo retinal model to examine inflammatory processes in diabetic retinopathy (DR) without animal testing. Porcine eyes were collected from a local abattoir, dissected, and cultivated for four days in five experimental groups: control group (Co), 25 mM and 50 mM mannitol groups (Man25, Man50) as osmotic controls, and 25 mM and 50 mM glucose groups (Glc25, Glc50) as diabetic groups. A TUNEL assay was used to determine relative cell death. Immunofluorescence and quantitative real-time polymerase chain reaction (qRT-PCR) were performed to detect inflammatory markers. An increase in the cell death rate in Man50 (30%), Glc25 (36%) and Glc50 (37%) compared to Co (12%) (p < 0.01, p < 0.001, p < 0.001, respectively) and between Glc25 and Man25 (21%) (p < 0.01) was found. Immunofluorescence staining and qRT-PCR analysis revealed a TNF-alpha increase in Glc25 compared to Man25 and Co. iNOS was increased in Glc25 vs. Man25 but not in Co vs. Glc25. iNOS gene expression was upregulated with Glc25 treatment compared to Co and Man25 groups. Expression levels of IL-6 and CD31 were significantly higher in Glc25 than in Co and Man25. Glucose treatment increased cell death and inflammation, prompting us to present a DR model for better understanding DR and testing new therapies.