Abstract
Purpose: :
The purpose of this study was to investigate the effect of mesenchymal stem cells (MSC) on a rat dry eye model induced by low humidity air flow.
Methods: :
Rat dry eye was induced by exposure to 2.4 m/sec dry air during 5 hrs after mechanical scraping of the corneal epithelium. The animals were randomly divided into the intact control group (intact eye, 5μl saline), DE control group (Dry eye induced, saline), HA group (Dry eye induced, 0.1% sodium hyaluronate), MSC-H group (Dry eye induced, high concentration of MSC), MSC-M group (Dry eye induced, medium concentration of MSC) MSC-L group (Dry eye induced, low concentration of MSC). Each test solutions were dropped from 30 min before initiation of exposure to air-flow, and then every 1 hr after initiation of exposure to air-flow (total 6 times). After air-flow exposure for 5 hrs, Schirmer tear test (STT) and fluorescence staining were performed. Then, the eye balls with conjunctiva were sampled for histomorphometry and immunohistochemistry of caspase-3 and poly(ADP-ribose) polymerase (PARP).
Results: :
In the dry eye induced control group, tear volume was significantly decreased and fluorescent intensity was markedly increased. In addition, the desquamations of corneal and conjunctival epithelium were detected and the thicknesses of the corneal and conjunctival epithelium were significantly reduced. The number of goblet cells of conjunctiva was markedly decreased and the numbers of caspase-3 and PARP positive cells were significantly increased. These means, dry eye conditions are relatively well induced by 5 hrs of dry air-flow exposure and apoptosis are may be involved in the mechanism of dry eye inductions. However, these dry eye conditions were significantly restored in HA and MSC treatment groups. Especially, the most favorable effects were shown in the medium concentration of MSC treated group.
Conclusions: :
Base on the result of this study, it is considered that mesenchymal stem cells have more favorable effects on the dry eye conditions as compared with hyaluronate. Therefore, it is expected that MSC has enough potentials which may be developed as a new ophthalmic drops on dry eye conditions.
Keywords: cornea: tears/tear film/dry eye • cornea: basic science • cornea: epithelium