Comparison of the beneficial effect of melatonin on recovery after cut and crush sciatic nerve injury: a combined study using functional, electrophysiological, biochemical, and electron microscopic analyses.
OBJECTIVE
Following tissue injury, melatonin is known to reduce detrimental effects of free radicals by stimulating antioxidant enzymes and also to inhibit posttraumatic polymorphonuclear infiltration. Beneficial effects after peripheral nerve injury have been suggested, but not studied in detail. Therefore, we aimed to elucidate the effects of melatonin on the recovery of the lesioned rat sciatic nerve by means of combined analysis.


METHODS
A total number of 90 rats were randomly distributed into six groups: control (group 1), sham-operated (group 2), sciatic nerve cut (group 3), sciatic nerve cut + melatonin treatment (group 4), sciatic nerve crush (group 5), and sciatic nerve crush + melatonin treatment (group 6). Melatonin was administered intraperitoneally at a dose of 50 mg/kg/day for 6 weeks. Recovery of function was analyzed by assessment of the sciatic functional index based on walking track analysis, somatosensory evoked potentials, biochemical quantification of malondialdehyde, antioxidant enzymes levels, and ultrastructural analysis.


RESULTS
Our data showed the beneficial effect of melatonin on sciatic nerve recovery. Rats treated with melatonin demonstrated better structural preservation of the myelin sheaths compared to the nontreated group. The biochemical analysis confirmed the beneficial effects of melatonin displaying lower lipid peroxidation and higher superoxide dismutase, catalase, and glutathione peroxidase activities in sciatic nerve samples in comparison to nontreated groups.


CONCLUSIONS
The beneficial effects of melatonin administration on the recovery of the cut and crush injured sciatic nerve may be attributed to its antioxidant properties. Based on these investigations, we think that our data would be helpful for clinicians who deal with peripheral nerve injuries.
Department of Anatomy, Akdeniz University Faculty of Medicine, 07070 Antalya, Turkey.
Yasemin
Y
Kaya
Levent
L
Sarıkcıoğlu
Mutay
M
Aslan
Ceren
C
Kencebay
Necdet
N
Demir
Narin
N
Derin
Doychin N
DN
Angelov
Fatoş Belgin
FB
Yıldırım
D000818:Animals; D000975:Antioxidants / Q000502:physiology / Q000627:therapeutic use*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D008550:Melatonin / Q000502:physiology / Q000627:therapeutic use*; D009186:Myelin Sheath / Q000187:drug effects* / Q000648:ultrastructure; D009409:Nerve Crush; D009416:Nerve Regeneration / Q000187:drug effects* / Q000502:physiology; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function; D012584:Sciatic Nerve / Q000187:drug effects / Q000293:injuries* / Q000502:physiology / Q000648:ultrastructure
D000975:Antioxidants; D008550:Melatonin