2019 Volume 38 Pages 3-8
The corneal protective effects of dodecahydrosqualene (DHS, squalane) were evaluated using an in vitro porcine short-term dry eye model. Fresh porcine eyes with an intact cornea were desiccated for 180 minutes, and administered a tear substitute made of castor oil (CO) solution for human use at a concentration of 0.5%, 1%, or 5%, or 0.5%, 1%, or 5% DHS solution in 60-, 90-, or 180-minute intervals. The staining score of methylene blue (MB), absorbance of MB extracted from the cornea, and the staining density of lissamine green (LG) increased with increasing administration intervals in eyes treated with all tear substitutes containing CO or DHS. A similar degree of corneal protection was observed with both tear substitutes at the same concentration and administration interval. However, DHS solutions exhibited greater corneal protection at a concentration of 0.5% in 180-minute intervals, 1% in 180-minute intervals, and 5% in 60-minute intervals than CO solutions under the same conditions. In addition, there were no significant differences in all MB or LG staining parameters between the control eyes and those administered 5% DHS solution in 60-minute intervals. Histopathological examination revealed the condition of the corneal epithelium treated with 5% DHS solution in 60-minute intervals resembled that in control eyes more than that in eyes administered 5% CO solution under the same treatment conditions. These results suggest that DHS can be used as an alternative lipid product for tear substitutes to treat tear film abnormalities such as keratoconjunctivitis sicca.
