A novel rare sugar inhibitor of murine herpes simplex keratitis

PURPOSE: To determine the therapeutic efficacy of a novel rare sugar, L-psicose, for the treatment of HSV-1 induced herpetic stromal keratitis (HSK) in a mouse eye model. METHODS: One rare sugar L-psicose was assayed for HSV-1 inhibition of in vitro virus adsorption. The IC(50) and IC(90) values of L-psicose were determined using plaque reduction assay (PRA) in CV-1 cell. Female Balb/c mice were corneally infected with HSV-1, strain KOS-GFP; A topical eye drop treatment of L-psicose was started 24 h after infection and continued four times daily for ten consecutive days. The severity of HSK was monitored by slit lamp examination in a masked fashion and Infectious HSV-1 shedding was determined by PRA. RESULTS: L-psicose was found to have anti-viral activity in vitro at an IC(50) dose of 99.5 mM and an IC(90) dose of 160 mM. Topical eye drop treatment with 200 mM L-psicose in PBS solution significantly reduced the severity of HSK compared to the mock treatment group. The in vivo mouse ocular model results of L-psicose therapy correlated with accelerated clearance of virus from eye swabs. CONCLUSION: The results suggest that topical treatment with rare sugar L-psicose has efficacy against HSK through inhibition of HSV-1.