Moderation of herpetic stromal keratitis by basic fibroblast growth factor

The effect of basic fibroblast growth factor (bFGF) on the evolution of herpes simplex virus (HSV) infection in eyes of rabbits was investigated. Rabbit eyes were infected with HSV-1 by a non-invasive inoculation and treated for 7 days with an eye drop solution containing either bovine bFGF (50 ng; three times daily), or bFGF diluent as control. The treatment started 2 hr, 24 hr or 96 hr post-inoculation (p.i.). Follow-up of clinical disease parameters, such as conjunctivitis, epithelial keratitis, stromal disease, corneal neovascularization and of viral isolation continued for 17 days. The most significant difference between bFGF and control treatments was observed in the development of stromal keratitis. The incidence of stromal disease in the bFGF treated group (2/16 eyes) was significantly lower than in the control group (11/12 eyes) (P = 0.0001), when bFGF was administered 2 hr or 24 hr p.i. The severity of the disease developed in the bFGF treated eyes was also milder than in the control eyes (determined by serial slit-lamp clinical examinations and by histologic sections). Such effect was not demonstrated if the treatment started 96 hr p.i. The same duration of viral shedding was obtained with bFGF treated eyes (2 hr, 24 hr, or 96 hr p.i.) and control eyes. Neither HSV-1-infected, nor sham-inoculated bFGF-treated eyes demonstrated increased neovascularization of the cornea, as compared with the corresponding vehicle-treated control eyes. This study demonstrates that bFGF treatment (starting 2-24 hr p.i.) decreased the occurrence and severity of herpetic stromal keratitis, without subsequent aggravation of corneal vascularization. This beneficial anti-inflammatory effect of bFGF may have future application in the treatment of the most devastating stage of herpetic corneal infection.