Transcranial Administration of Nano Pulse Laser Therapy for Blast Induced Neurotrauma
Treatment and care for mild traumatic brain injury (mTBI) is often overlooked in TBI research, yet it is the most common form of TBI. Moderate-severe TBI is accompanied by distinct behavioral and physiological characterizations, while mTBI presents variably. mTBI is a promising target for non-invasive treatments as it has detrimental consequences (anxiety, depression, memory loss, Alzheimer’s Disease, and Chronic Traumatic Encephalopathy) but does not render surgical intervention. We propose application of Nano-Pulse Laser Therapy (NPLT) which works by combining neuroprotective near-infrared light and therapeutic optoacoustically generated low intensity ultrasound waves, as a prophylactic for high-risk populations. Our previous research has shown a reduction in neuronal death and microglial activation in a rat model of focal TBI. Our current work aims to determine the viability of NPLT as both a prophylactic treatment for a single blast TBI (bTBI) and through multiple applications as a therapeutic for repeated bTBI. In our first aim, male adult Sprague Dawley rats were treated with NPLT 24 hours prior to being subjected to blast TBI. Then the animals were assessed using Beam Balance, Beam Walk, Neuroscore, and Morris Water Maze tests. After behavioral tests the animals were sacrificed for histology. In our second aim, male adult Sprague Dawley rats were given repeated blast injuries 48 hours apart. Within the injuries there were given NPLT pre-treatment, intermediate (between the first and second injury) and post injury treatments. The animals then undergo the same assessments as the first aim. In the single injury regimen TBI animals showed increased latencies in the Beam Walk and Morris Water Maze tasks, while NPLT treated and injured animals showed no deficits. Histological data pointed to a decrease in microglial cells in the NPLT+Sham animals and TBI animals, but only a significant reduction in microglial staining in the NPLT+Sham group. In the second experimental design TBI animals showed a consistent decrease in microglial cells but an increase in microglial staining, while the NPLT treated animals did not show any differences when compared to Sham. Changes in microglial staining and cell count may be indicative of changes in cellular morphology. With this work we hope to shed light on practical applications of non-invasive treatments, alleviate the burden of mild TBI, and move one step closer to characterizing the effects of NPLT.