A porcine cornea model for testing corneal storage media formulations

ABSTRACT

Purpose: The COVID-19 pandemic further increased the lack of human donor corneas for research purposes. In this study we established a porcine cornea model for testing corneal storage media formulations. Methods: 14 corneas were extracted from porcine eye globes obtained from local slaughterhouse after povidone-iodide 5% disinfection. The tissues were stored in standard corneal culture medium Eusol-C (AL.CHI.MI.A. SRL) at 4°C. After 0, 3, 7, and 14 days the tissues were analyzed in quintuplicate at T0 and in triplicate for the other timepoints with Optical coherence tomography (OCT) for central corneal thickness (CCT). The corneal transparency was evaluated by measurement of optical density using a homemade instrument. At each timepoint corneal endothelium was stained with trypan blue and alizarin red and evaluated with an inverted microscope with 100 X magnification (Nikon) for endothelial cell density (ECD) and morphology in both whole cornea and in dissected corneal lamellas consisting of Descemet's membrane (DM) and endothelial cells (EC). Results: The corneal transparency diminished along storage time of approximately 10%. Corneal thickness increased of approximately 100 μm at day 14. ECD decreased of approximately 10% from T0 to the final T14 timepoint leading to an average of 2800 cells/mm2 at T14. The dissected DM corneal lamellas allowed good EC morphology evaluation which was well preserved after 14 days at 4°C. The flaccidity of porcine corneas made OCT measurements difficult and CCT showed slight variability. Conclusions: We established a porcine cornea model that allowed reproducible corneal evaluation of ECD, endothelial morphology CCT and transparency in whole porcine corneas and dissected DM corneal lamellas. In conclusion, the evaluation of porcine corneal tissues allowed to compensate to the lack of human donor tissues for research use, providing a reliable tool for testing corneal storage media formulations.