title: Acute neuroprotective effects of extremely low-frequency electromagnetic fields after traumatic brain injury in rats.
abstract: Traumatic brain injury commonly has a result of a short window of opportunity between the period of initial brain injury and secondary brain injury, which provides protective strategies and can reduce damages of brain due to secondary brain injury. Previous studies have reported neuroprotective effects of extremely low-frequency electromagnetic fields. However, the effects of extremely low-frequency electromagnetic fields on neural damage after traumatic brain injury have not been reported yet. The present study aims to investigate effects of extremely low-frequency electromagnetic fields on neuroprotection after traumatic brain injury. Male Sprague-Dawley rats were used for the model of lateral fluid percussion injury, which were placed in non-electromagnetic fields and 15 Hz (Hertz) electromagnetic fields with intensities of 1 G (Gauss), 3 G and 5 G. At various time points (ranging from 0.5 to 30 h) after lateral fluid percussion injury, rats were treated with kainic acid (administered by intraperitoneal injection) to induce apoptosis in hippocampal cells. The results were as follows: (1) the expression of hypoxia-inducible factor-1α was dramatically decreased during the neuroprotective time window. (2) The kainic acid-induced apoptosis in the hippocampus was significantly decreased in rats exposed to electromagnetic fields. (3) Electromagnetic fields exposure shortened the escape time in water maze test. (4) Electromagnetic fields exposure accelerated the recovery of the blood-brain barrier after brain injury. These findings revealed that extremely low-frequency electromagnetic fields significantly prolong the window of opportunity for brain protection and enhance the intensity of neuroprotection after traumatic brain injury.
authors.affiliation: Department of Neurosurgery, Xijing Hospital, The Fourth Military Medical University, 17 West Changle Road, Xi'an 710032, China. yangyang19800627@163.com
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.forename: Yan-Gang
authors.initials: YG
authors.lastname: Wang
authors.forename: Zhou
authors.initials: Z
authors.lastname: Fei
authors.forename: Jun
authors.initials: J
authors.lastname: Zhong
authors.forename: Li-Zhou
authors.initials: LZ
authors.lastname: Wei
authors.forename: Qian-Fa
authors.initials: QF
authors.lastname: Long
authors.forename: Wei-Ping
authors.initials: WP
authors.lastname: Liu
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000528:radiation effects; D001930:Brain Injuries / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy*; D004307:Dose-Response Relationship, Radiation; D004599:Electric Stimulation Therapy / Q000379:methods*; D004574:Electromagnetic Fields; D016489:Head Injuries, Closed / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy*; D008297:Male; D011829:Radiation Dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D016896:Treatment Outcome