Therapeutic Effects of Human Placental Extracts Eye Drops in Experimental Dry Eye and Alkali Burn

Purpose: To evaluate the efficacy of human placental extract (HPE) eye drops compared to that of carboxymethylcellulose (CMC) and human peripheral blood serum (HPBS) eye drops in a mouse model of experimental dry eye (EDE) and corneal alkali burns. Methods: EDE and alkali burn models were induced in C57BL/6 mice using desiccating stress and NaOH, respectively. In both the EDE and alkali burn models, treatment groups received CMC, HPBS, or HPE eye drops. In EDE model, tear volume, tear break-up time (TBUT), and total corneal fluorescein staining score (CFSS) were measured. ROS were detected with 2',7'-dichlorodihydrofluorescein diacetate. Conjunctiva goblet cells were identified by periodic acid-Schiff staining, and corneal epithelial apoptosis was detected by TUNEL assay. In alkali burn model, the area and diameter of epithelial defects were assessed in each group. Results: In the EDE model, tear volume, CFSS, and epithelial apoptosis were significantly improved in all treatment groups. Compared to the CMC group, the HPE group showed a better improvement in the production of tear volume, TBUT, CFSS, ROS, and conjunctiva goblet cell density. There were no significant differences in parameters between the HPBS and HPE groups except for TBUT at 14 days. In the alkali burn model, the HPE group had a smaller area compared to the control and CMC groups and a shorter diameter compared to the control group. Conclusion: HPE eye drops were as effective as HPBS eye drops in improving the clinical signs and ocular surface oxidative damage of EDE and in promoting corneal epithelialization after alkali burn.