Anti-edema effect of melatonin on spinal cord injury in rats.
OBJECTIVE
To determine the anti-edema effects of melatonin on spinal cord injury (SCI) in rats.


METHODS
A total of 150 adult male Sprague-Dawley rats were randomly allocated to the following three groups (n=50): a sham group which underwent laminectomy without dural compression; an SCI group, which underwent laminectomy followed by SCI and received saline i.p. immediately after injury and then daily for 2 days; an MT group, which underwent laminectomy followed by SCI and received a 100 mg/kg dose of melatonin i.p. immediately after SCI and then daily for 2 days. The cords were removed at 12, 24, 48 and 72 h after surgery in every group. Spinal cord edema was evaluated by determining the spinal cord water content. Expressions of AQP4 and GFAP positive cells in injured spinal cord were detected by immunohistochemical staining, and protein expressions of AQP4 and GFAP were detected by Western blotting.


RESULTS
Spinal cord water content was obviously increased after SCI, which was maintained almost unchanged by melatonin treatment (100 mg/kg) at 12 h after injury but was significantly reduced from 24 h to 72 h. The expressions of AQP4 and GFAP increased in the injured spinal cord segments, which were decreased by melatonin treatment (100 mg/kg) between 24 h and 72 h after SCI.


CONCLUSIONS
Melatonin (100 mg/kg) had anti-edema effects after acute SCI probably by down-regulating the expression level of AQP4 protein, and it may eliminate astrocytic swelling after SCI through down-regulating the expression level of GFAP protein.
Department of Orthopedics, General Hospital of Shenyang Military Area Command of Chinese PLA, Rescue Center of Severe Wound and Trauma of Chinese PLA, Shenyang 110016, China.
Xinwei
X
Liu
Department of Orthopedics, General Hospital of Shenyang Military Area Command of Chinese PLA, Rescue Center of Severe Wound and Trauma of Chinese PLA, Shenyang 110016, China.
Yu
Y
Wang
The Medical Department, No. 100 Hospital of Chinese PLA, Suzhou 215007, China.
Jishun
J
Yang
Department of Emergency, General Hospital of Shenyang Military Area Command of Chinese PLA, Rescue Center of Severe Wound and Trauma of Chinese PLA, Shenyang 110016, China.
Yunen
Y
Liu
Department of Orthopedics, General Hospital of Shenyang Military Area Command of Chinese PLA, Rescue Center of Severe Wound and Trauma of Chinese PLA, Shenyang 110016, China.
Dapeng
D
Zhou
Department of Emergency, General Hospital of Shenyang Military Area Command of Chinese PLA, Rescue Center of Severe Wound and Trauma of Chinese PLA, Shenyang 110016, China.
Mingxiao
M
Hou
Department of Orthopedics, General Hospital of Shenyang Military Area Command of Chinese PLA, Rescue Center of Severe Wound and Trauma of Chinese PLA, Shenyang 110016, China.
Liangbi
L
Xiang
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology*; D051401:Aquaporin 4 / Q000378:metabolism; D001834:Body Water / Q000378:metabolism; D015536:Down-Regulation; D004487:Edema / Q000517:prevention & control*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007796:Laminectomy; D008297:Male; D008550:Melatonin / Q000008:administration & dosage / Q000494:pharmacology*; D011897:Random Allocation; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000737:chemistry / Q000378:metabolism; D013119:Spinal Cord Injuries / Q000150:complications*
D000975:Antioxidants; C496032:Aqp4 protein, rat; D051401:Aquaporin 4; D005904:Glial Fibrillary Acidic Protein; D008550:Melatonin
edema; melatonin; rats; spinal cord injury