Transcranial photobiomodulation prevents PTSD-like comorbidities in rats experiencing underwater trauma

Yong Li,Quanguang Zhang,Lorelei Tucker,Yan Dong,Baocheng Yang,Michael R Hamblin,Xuemei Zong,Luodan Yang

doi:10.1038/s41398-021-01389-5

Abstract

Maladaptive fear memory processing after a traumatic event is a major contributor to the development of the comorbidities related to posttraumatic stress disorder (PTSD). An intervention to normalize this process could be a first-line treatment to prevent PTSD development. However, little progress has been made in identifying interventions that can prevent trauma survivors from developing PTSD. A treatment that could help trauma survivors cope with traumatic memories and decrease the prevalence of PTSD is thus in high demand. This study was designed to investigate the potential beneficial effects of early photobiomodulation (PBM) interventions to prevent PTSD-like comorbidities in animals. PTSD-like comorbidities in rats were induced by an underwater trauma (UWT) procedure, followed by multiple swimming sessions on later days for memory recall. Immediately after UWT and swimming, rats were restrained with or without PBM treatment (808 nm, 25 mW/cm2, 3 J/day). PTSD-like commodities, such as anxiety-like behavior, depression-like behavior, and cognitive dysfunction, were reproduced in UWT-rats. These comorbidities, however, could be prevented by early PBM interventions. By measuring the expression of immediate early genes (IEGs) as neuronal activity markers, we found that PBM treatment differentially regulated Arc and c-fos expression in the hippocampus and amygdala, two PTSD-related brain regions. Additionally, PBM boosted ATP production and regulated protein expression in the hippocampus following stress. Our results demonstrate that PBM can modulate brain activity in response to traumatic and stressful events and that early PBM intervention can prevent the occurrence of PTSD-like comorbidities in rats.

Highlights

Posttraumatic stress disorder (PTSD) is a psychiatric disorder that develops after individual experiences or witnesses a traumatic event
We first assigned three groups of rats (Fig. 1A) for exploring the long-term treatment effect from PBM: (I) ctrl-group rats were subjected to swimming on days 0–7 without restraint after swimming; (II) underwater trauma (UWT)-group rats were subjected to UWT at day 1 and swimming reminder sessions on day 2–7, followed by immediate restraint for 2 min after removal from the water tank; (III) PBM-group rats underwent the same procedure as the UWT-group but received PBM treatment under restraint
These results suggest that UWT induced an anxiety-like phenotype in the UWT-group and that PBM-treatment could prevent this anxiety-like behavior

Summary

Introduction

Posttraumatic stress disorder (PTSD) is a psychiatric disorder that develops after individual experiences or witnesses a traumatic event. The symptoms of PTSD include flashbacks and intrusive memories, avoidance of trauma-associated cues, negative changes in cognition, and hyperarousal[1]. PTSD patients often develop depressive disorders, anxiety disorders, and substance abuse. The current prevailing treatment strategy to relieve the comorbidities of PTSD relies upon psychotherapy[3], cognitive behavioral therapy, and pharmacological therapy[4], primarily using antidepressants and anti-anxiety medications. Many patients display no therapeutic benefits from antidepressants and anti-anxiety medication, and the frequent and substantial side effects of these drugs are of significant concern[5]. A new treatment that could relieve the comorbidities and symptoms of PTSD is of the utmost necessity. Fear memory develops in three sequential phases: acquisition, storage, and retrieval[6]

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