Photobiomodulation therapy: Location-dependent effects on memory and recovery in male adult rats with spinal cord injury

Spinal cord injuries (SCIs) can cause significant physical and emotional challenges for individuals as a result of inflammation and cell death. This study investigates the effectiveness of photobiomodulation therapy (PBMT) in reducing inflammation and memory impairment through the use of 3 specific treatment protocols. Forty male rats (180-200 g) were divided into 5 groups: Control; SCI model; and SCI with 3 different PBMT protocols. The rats underwent behavioral tests (Novel Object Recognition and Shuttle Box), histological examination (H&E and Nissl staining), and protein analysis (HDAC2, NF-kB [p65], IkB-α, and BDNF) using Western blot of medial prefrontal cortex (mPFC) and hippocampal tissues. PBMT effectively decreased NF-κB levels in the mFPC in all 3 PBMT protocols. The third PBMT3 protocol with the highest energy delivery, which included both the spinal cord and skull had the greatest impact on regulating the expression of this inflammatory factor. Behavioral assessments revealed that the PBMT3 protocol led to the most significant enhancement in cognition. The therapeutic effects of PBMT on memory are thought to be mediated by the enhancement of neurotrophic factors such as BDNF and the reduction of inflammatory mediators, which can impair hippocampal and mPFC function.