Related Experiment Videos
Timolol induces HSV-1 ocular shedding in the latently infected rabbit
Abstract:
Timolol iontophoresis into the eye can induce herpes simplex virus type 1 (HSV-1) shedding in rabbits latently infected with HSV-1 strain McKrae. Anodal iontophoresis of 0.01% timolol was done at 0.8 mAmp for 8 min once a day for 3 consecutive days. Viral shedding was determined by the presence of HSV-1 in the preocular tear film obtained by eye swabs. In two experiments, iontophoresis of 0.01% timolol resulted in all eyes (18/18) shedding HSV-1 for an average duration of 4.3 days. When 5.0% timolol was applied topically to rabbit eyes supersensitized by iontophoresis of 6-hydroxydopamine (6-HD), all eyes (10/10) shed virus for an average duration of 2.9 days. All eyes (12/12) receiving iontophoresis of 6-HD, pre- and posttreatment with topical application of 5.0% timolol, and posttreatment with topical application of 1.0% epinephrine shed virus for an average duration of 3.6 days. Eyes treated with topical application of 5.0% timolol alone showed no difference in HSV-1 ocular shedding, compared with untreated eyes. We concluded that both iontophoresis of 0.01% timolol and topical application of 5.0% timolol to adrenergically supersensitized eyes induced HSV-1 shedding reliably and with a high frequency, and that topically applied timolol does not block the HSV-1 ocular shedding induced by epinephrine in adrenergically supersensitized eyes.
Insights
Timolol iontophoresis can trigger herpes simplex virus type 1 (HSV-1) shedding in rabbits. Topical timolol also induced HSV-1 shedding in supersensitized eyes, but did not block epinephrine-induced shedding.
Area of Science:
- Ophthalmology
- Virology
- Pharmacology
Background:
- Herpes simplex virus type 1 (HSV-1) can establish latent infections in the eye.
- Ocular HSV-1 reactivation leads to viral shedding and potential disease.
- Timolol is a beta-blocker commonly used in ophthalmology.
Purpose of the Study:
- To investigate the effect of timolol, delivered via iontophoresis and topical application, on HSV-1 shedding in latently infected rabbits.
- To determine if timolol influences HSV-1 shedding induced by adrenergic supersensitization.
Main Methods:
- Anodal iontophoresis of 0.01% timolol was administered to rabbit eyes.
- Topical application of 5.0% timolol was used on eyes supersensitized with 6-hydroxydopamine (6-HD).
- Viral shedding was assessed by detecting HSV-1 in preocular tear film.
Main Results:
- Iontophoresis of 0.01% timolol induced HSV-1 shedding in all treated eyes (18/18) for an average of 4.3 days.
- Topical 5.0% timolol on 6-HD supersensitized eyes caused shedding in all eyes (10/10) for 2.9 days.
- Timolol did not prevent epinephrine-induced HSV-1 shedding in supersensitized eyes.
Conclusions:
- Timolol, via iontophoresis or topical application to adrenergically supersensitized eyes, reliably induces HSV-1 ocular shedding.
- Topical timolol does not inhibit HSV-1 shedding triggered by epinephrine in supersensitized eyes.