Beneficial effects of melatonin on reperfusion injury in rat sciatic nerve.
Studies have shown that ischemia-reperfusion (I/R) produces free radicals leading to lipid peroxidation and to damage of the nervous tissue. Melatonin, a main secretory product of the pineal gland, has free radical scavenging and antioxidant properties and has been shown to diminish I/R injury in many tissues. There are a limited number of studies related to the effects of melatonin on I/R injury in the peripheral nervous system. Therefore, in the present study, the protective effect of melatonin was investigated in rats subjected to 2 hr of sciatic nerve ischemia followed by 3 hr of reperfusion. Following reperfusion, nerve tissue samples were collected for quantitative assessment of malondialdehyde (MDA), an oxidative stress marker, and superoxide dismutase (SOD), a principal antioxidant enzyme. Samples were further evaluated at electron microscopic level to examine the neuropathological changes. I/R elevated the concentration of MDA significantly while there was a reduction at SOD levels. Melatonin treatment reversed the I/R-induced increase and decrease in MDA and SOD levels, respectively. Furthermore, melatonin salvaged the nerve fibers from ischemic degeneration. Histopathologic findings in the samples of melatonin-treated animals indicated less edema and less damage to the myelin sheaths and axons than those observed in the control samples. Our results suggest that administration of melatonin protects the sciatic nerve from I/R injury, which may be attributed to its antioxidant property.
Sayan
Hale
H
Department of Physiology, Medical School, Zonguldak Karaelmas University, Turkey. halesayan@yahoo.com
Ozacmak
V Haktan
VH
Ozen
Oguz Aslan
OA
Coskun
Omer
O
Arslan
S Oktay
SO
Sezen
S Cem
SC
Aktas
R Gulhan
RG
D000818:Animals; D001369:Axons / Q000187:drug effects / Q000648:ultrastructure; D019610:Cytoprotection; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008550:Melatonin / Q000494:pharmacology*; D009186:Myelin Sheath / Q000187:drug effects / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010523:Peripheral Nervous System Diseases / Q000473:pathology / Q000517:prevention & control*; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000473:pathology / Q000517:prevention & control*; D012583:Schwann Cells / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D012584:Sciatic Nerve / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D013482:Superoxide Dismutase / Q000187:drug effects / Q000378:metabolism
D018696:Neuroprotective Agents; D008315:Malondialdehyde; D013482:Superoxide Dismutase; D008550:Melatonin