Inhibitory effect of rapamycin-deep eutectic solvent eye drops on corneal allograft rejection in mice and its mechanism

Objective To investigate the inhibitory effect of rapamycin (RAPA)-deep eutectic solvent (DES) eye drops on corneal allograft rejection in mice and its mechanism. Methods CCK-8 assay was used to measure the influence of 10 types of DES on the viability of human corneal epithelial cells (HCECs), and the DES with a significantly higher cell viability than the control group was selected for characterization to obtain the most suitable DES. BALB/c mice and New Zealand white rabbits were used to evaluate the biocompatibility of the most suitable DES. The mice were randomly divided into normal group, phosphate solution (PBS) group, DES group, and RAPA-DES group. The mice in normal group were fed normally, and those in the PBS group, the DES group, and the RAPA-DES group were administrated PBS, DES, and RAPA-DES solution, respectively, to the right eye after corneal transplantation. On the next day, a slit lamp was used to observe the survival of corneal grafts, and the survival percentage of corneal grafts was anal