Dose-finding study of phototherapy on stroke outcome in a rabbit model of ischemic stroke.

Abstract Goal While transcranial laser therapy (TLT) has been shown to improve clinical outcome in a preclinical model of ischemic stroke, optimal timing and dosing has yet to be tested adequately. The purpose of this study was to assess clinical stroke outcome in the Rabbit Small Clot Embolic Model (RSCEM) with dose escalating TLT. Methods We utilized the rabbit small clot embolic stroke model (RSCEM) using dose-escalating regimens. Behavioral analysis was conducted at 24 h post-embolization, allowing for the determination of the effective stroke dose (ES 50 ) or clot amount (mg) that produces neurological deficits in 50% of a group of rabbits. Using the RSCEM, a treatment is considered beneficial if it significantly increases the ES 50 compared with the control group. Findings A significant behavioral benefit was seen at triple TLT of 111 mW treatment of 2 min at 2 h post-embolization (6.47 ± 1.06, n = 17; p = 0.03), compared with the previously used regimen (3.09 ± 0.51, n = 15). Conclusion TLT results in significant behavioral improvement when administered 2 h post-embolization. Studies are warranted to evaluate this therapy in combination with thrombolysis.