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Beneficial effects of endogenous and exogenous melatonin on neural reconstruction and functional recovery in an animal model of spinal cord injury
Author(s) -
Park Sookyoung,
Lee SangKil,
Park Kanghui,
Lee Youngjeon,
Hong Yunkyung,
Lee Seunghoon,
Jeon JeCheol,
Kim JooHeon,
Lee SangRae,
Chang KyuTae,
Hong Yonggeun
Publication year - 2012
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/j.1600-079x.2011.00925.x
Subject(s) - melatonin , endogeny , medicine , endocrinology , neuroprotection , spinal cord , muscle atrophy , spinal cord injury , nitric oxide synthase , skeletal muscle , hindlimb , biology , nitric oxide , neuroscience
The purpose of this study was to investigate the beneficial effects of endogenous and exogenous melatonin on functional recovery in an animal model of spinal cord injury (SCI). Eight‐week‐old male Sprague‐Dawley (SD, 250–260 g) rats were used for contusion SCI surgery. All experimental groups were maintained under one of the following conditions: 12/12‐hr light/dark (L/D) or 24:0‐hr constant light (LL). Melatonin (10 mg/kg) was injected subcutaneously for 4 wk, twice daily (07:00, 19:00). Locomotor recovery, inducible nitric oxide synthase (iNOS), glial fibrillary acidic protein gene expression, and muscle atrophy‐related genes, including muscle atrophy F‐box (MAFbx) and muscle‐specific ring‐finger protein 1 (MuRF1) gene expression were evaluated. Furthermore, autophagic signaling such as Beclin‐1 and LC3 protein expression was examined in the spinal cord and in skeletal muscle. The melatonin treatment resulted in increased hind‐limb motor function and decreased iNOS mRNA expression in the L/D condition compared with the LL condition ( P < 0.05), indicating that endogenous melatonin had neuroprotective effects. Furthermore, the MAFbx, MuRF1 mRNA level, and converted LC3 II protein expression were decreased in the melatonin‐treated SCI groups under the LL ( P < 0.05), possibly in response to the exogenous melatonin treatment. Therefore, it seems that both endogenous and exogenous melatonin contribute to neural recovery and to the prevention of skeletal muscle atrophy, promoting functional recovery after SCI. Finally, this study supports the benefit of endogenous melatonin and use of exogenous melatonin as a therapeutic intervention for SCI.