title: Does circadian rhythm disruption induced by light-at-night has beneficial effect of melatonin on sciatic nerve injury?
abstract: Melatonin stimulates peripheral nerve regeneration. However, the precise effect of Melatonin on nerve repair in dark period have not been clarified. The aim of the present study was to investigate the effect of melatonin on sciatic nerve injury after melatonin was given to rats in the morning or evening by means of combined analysis. This is the first study to investigate the influence of melatonin on sciatic nerve in cut injury two different times of the day. 60 adult female Wistar rats were divided into 4 groups: control (Group 1), sham-operated (Group 2), sciatic nerve cut+melatonin treatment in light (Group 3), sciatic nerve cut+melatonin treatment in dark (Group 4). Melatonin was administered intraperitoneally at dose of 50 mg/kg/day for six weeks. Recovery of function was analyzed by structural (biochemical properties of the antioxidant levels and ultrastructural analysis) and functional analyses (Sciatic function index, pinch test). The data demonstrated beneficial effect of melatonin in light period. However significant beneficial effect of melatonin was detected on the recovery of the cut sciatic nerve in dark period. Melatonin treatment was unable to influence on the recovery of the cut sciatic nerve in dark period. This means that the effect of melatonin the recovery of the cut injured sciatic nerve depends on the time of treatment may be attributed to its circadian rhythm.
authors: Department of Anatomy, Akdeniz University Faculty of Medicine, 07070 Antalya, Turkey. Electronic address: ya_behram@hotmail.com.
authors: Yasemin
authors: Y
authors: Kaya
authors: Levent
authors: L
authors: Sarikcioglu
authors: Fatoş Belgin
authors: FB
authors: Yildirim
authors: Mutay
authors: M
authors: Aslan
authors: Necdet
authors: N
authors: Demir
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D008550:Melatonin / Q000008:administration & dosage* / Q000378:metabolism; D009416:Nerve Regeneration / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function / Q000187:drug effects*; D012584:Sciatic Nerve / Q000187:drug effects / Q000293:injuries; D020426:Sciatic Neuropathy / Q000378:metabolism / Q000473:pathology
chemical_list: D000975:Antioxidants; D008550:Melatonin
keywords: Antioxidant enzymes; CAT; Circadian rhythm; EDTA-GPx; HCl; MDA; Melatonin; NADP; NO; NOS; Nerve injury; SFI; SOD; TBARS; catalase; glutathione peroxidase; hydrochloric acid; malondialdehyde; nicotinamide adenine dinucleotide phosphate; nitric oxide; nitric oxide synthase; sciatic functional index; superoxide dismutase; thiobarbituric acid-reactive substances