Effect of infrared transcranial low level laser therapy and methylene blue on chronic stress-induced learning and memory impairment in mice

Abstract

Methylene Blue (MB) and Transcranial Photobiomodulation (tPBM) can improve mitochondrial respiration and thus protect nerve cells. Both of these interventions increase the expression of cytochrome oxidase in the intraceular conditions. The effects of tPBM and MB in the treatment of learning and memory disorders have already been reported. In this study, the effects of tPBM and MB in combination or alone in learning and memory disorders due to Unpredictable Chronic Mild Stress (UCMS) in mice are studied. Materials and methods: 60 male mice (BALB / c) were randomly assigned into 5 groups (1) control group. (2) laser Sham + normal saline (NS) group. (3) tPBM + NS. (4) laser Sham + MB. (5) tPBM + MB. All groups, except the control group, were undergone UCMS conditions for 4 weeks and therapeutic interventions were performed simultaneously. An Elevated Pluse Maze (EPM) test was used to measure the amount of anxiety. Novel Object Recognition (NOR) and Barnes Maze tests were used to measure learning and memory performance. Serum levels of cortisol and levels of NO, ROS, TAC, GPx and SOD in brain tissue were measured by spectrophotometric methods. Results: Behavioral tests have shown that UCMS causes learning and memory damage, and treatment with tPBM and MB have returned these injuries to normal conditions. The activity of NO, ROS, SOD levels as well as serum cortisol levels in the brain significantly increased in the laser sham + NS group compared with the control animals. However, in the laser sham + NS group, the activity of GPx and TAC levels decreased.