Effect of a beta-adrenergic antagonist, propranolol, on induced HSV-1 ocular recurrence in latently infected rabbits.

PURPOSE: Propranolol, a beta-adrenergic antagonist, has been shown to block hyperthermically-induced ocular recurrence of HSV-1 in mice and reduce spontaneous ocular viral shedding and herpetic corneal lesions in latently infected rabbits. The present study was performed to determine the effect of propranolol on epinephrine iontophoresis-induced ocular recurrence and immunosuppression-induced ocular recurrence in the rabbit eye model.
METHODS: New Zealand white rabbits were infected with HSV-1 strain 17Syn+ or McKrae. After latency was established, the animals were injected intramuscularly with saline (placebo), or propranolol (5-200 mg/kg) twice daily, and then induced with epinephrine iontophoresis or cyclophosphamide and dexamethasone administration. Tear film swabs were cultured to determine the frequency of viral shedding.
RESULTS: Propranolol administered at a range of doses did not affect the frequency or duration of viral shedding following epinephrine or cyclophosphamide/dexamethasone induction as compared to saline treatment.
CONCLUSION: These results demonstrate that propranolol does not significantly reduce ocular HSV-1 shedding following induction by epinephrine iontophoresis or immunosuppression. By inference, these results suggest two possibilities: (1) that viral pathways leading to spontaneous and induced shedding of virus are under separate control mechanisms or (2) in rabbits, these inducers are of such potency that propranolol is ineffectual.