Effect of melatonin on cerebral edema in rats.
OBJECTIVE
Melatonin (5-methoxy-N-acetyltrypamine), a chemical naturally produced in the pineal gland, has been suggested to be a free radical scavenger and an antioxidant. In the present study, the effect of melatonin on cold-induced brain edema was evaluated by determination of cerebral water content, blood-brain barrier permeability, and areas of infarct; the effects were also studied histopathologically.


METHODS
Brain edema was produced in rats by creating a lesion via cortical freezing. Animals were separated into four groups: sham-operated (craniectomy only); control (cold injury); sham-vehicle (cold injury plus saline); and melatonin treatment (cold injury plus melatonin). Melatonin was administered (50 mg/kg intraperitoneally) 15 minutes after the cold injury was induced. Twenty-four hours later, tissue samples from the core, from the periphery of the cold-injured hemisphere, and from the contralateral hemisphere symmetrical to the cold injury were obtained.


RESULTS
Melatonin treatment reduced edema (mean +/- standard deviation; 86.22 +/- 1.54% in the control group versus 80.78 +/- 2.76% in the melatonin treatment group, P < 0.001) and blood-brain barrier permeability (45.34 +/- 2.75% in the control group versus 38.26 +/- 3.40% in the melatonin treatment group, P < 0.001) at the periphery of cold injury. Area of infarct reduced from 5.84 +/- 0.58% in the control group to 3.30 +/- 0.89% in the melatonin treatment group (P < 0.001). The effect of melatonin was also confirmed histopathologically.


CONCLUSIONS
Melatonin was found to be neuroprotective in instances of cold-induced brain edema. Thus, melatonin may be a valuable therapeutic agent in the treatment of cerebral edema.
Görgülü
A
A
Department of Neurosurgery, School of Medicine, University of Trakya, Edirne, Turkey. askingorgulu@hotmail.com
Palaoğlu
S
S
Ismailoğlu O
Tuncel
M
M
Sürücü
M T
MT
Erbil
M
M
Kilinç
K
K
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001812:Blood-Brain Barrier / Q000187:drug effects; D001929:Brain Edema / Q000473:pathology*; D002540:Cerebral Cortex / Q000473:pathology; D016166:Free Radical Scavengers / Q000494:pharmacology*; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D008854:Microscopy, Electron; D051381:Rats; D014882:Water-Electrolyte Balance / Q000187:drug effects
D000975:Antioxidants; D016166:Free Radical Scavengers; D008550:Melatonin