Effects Of Melatonin On Expression Of TNF-α、IL-1βin Rats With Acute Spinal Cord Injury

Background and ObjectiveSpinal cord injury (SCI) is usually damaged from all causes nervous system,often resulting in severe motor and sensory dysfunction.Primary injury and spinalcord injury, including the primary factors of secondary injury. Primary injury is aprocess instantaneous and irreversible characteristics. And secondary damage occurson the basis of the primary injury, the process can be reversed with thecharacteristics. A large number of inflammatory cell infiltration after spinal cordinjury and a large number of inflammatory cytokine production is a major factorleading to spinal cord injury.Secondary injury due to spinal cord can be reversed,and therefore, the control of secondary SCI injury is one of the important goals ofearly treatment.Melatonin is a neuroendocrine hormone, which is secreted by thepineal gland,possess immunomodulatory,anti-oxidation, anti-inflammatory and otherbiological functions,Early experiments have demonstrated the role of melatoninsecretion can promote neurotrophic factor (NGF), but its after spinal cord injury andinflammatory cytokines TNF-ɑ role of IL-1β is unclear.This study examined theeffects of melatonin on spinal cord injury after different periods of inflammatorycytokines TNF-ɑ, IL-1β expression, the role of MT SCI secondary injury to further clarify MT for SCI protection mechanisms.Research Subjects and MethodsA total of108SD rats were randomly divided into three groups:Sham group,only laminectomy without spinal cord injury, SCI group and the SCI+MT groupusing the modified Allen’s method of establishing T12spinal cord injury model.100mg/kg of MT was given to the SCI+MT group and5%ethanol to SCI group at10min after the model establishment．3groups rats were detected by ELISA in serumafter spinal cord injury the expression of TNF-ɑ、IL-1β and RT-PCR method for thedetermination injured spinal cord tissue expression of TNF-ɑ mRNA.At12h,6samples of spinal cord were taken in each group for histological examination usingHE and immunohistochemical SP staining methods.Using SPSS17.0statisticalsoftware for data processing, data between the groups using ANOVA. Whenhomogeneity of variance between groups were compared using t test, whenheterogeneity of variance, using Tamhane, s T2test, inspection standards take ɑ=0.05.Results1. SCI+MT group and SCI group after spinal cord injury TNF-ɑ contentdynamic variation trend for1h expression was significantly increased,12h peak,72h level close to Sham group，which is the serum IL-1βsame trend.The same point intime the rats serum TNF-ɑ SCI group had the highest protein content, SCI+MTgroup followed, Sham group was the lowest.2. SCI+MT group and SCI group after spinal cord injury TNF-ɑ mRNAcontent dynamic variation trend for1h expression was significantly increased,12hpeak,72h level close to Sham group.The same point in time the rats spinal cordtissue TNF-ɑ mRNA levels and serum TNF-ɑ SCI group had the highest proteincontent, SCI+MT group followed, Sham group was the lowest.3. Immunohistochemical staining showed that spinal cord tissue TNF-ɑ proteinmainly in neurons and glial cells in the cytoplasm and nucleus,SCI group was the highest,SCI+MT group followed,Sham group was the lowest,HE staining showedthat the SCI+MT group compared with SCI pathological changes were significantlyreduced.The difference between the groups was statistically significant (p <0.01).4.At each time point, SCI group and SCI+MT group, BBB score differencewas not statistically significant (P>0.05).Conclusion1.MT reduce the content of TNF-ɑ and tissue TNF-ɑ mRNA in rat spinal cordserum to mitigate damage secondary to spinal cord injury.2.MT reduce the content of IL-1β in rat spinal cord serum to mitigate damagesecondary to spinal cord injury.3.In the short term, MT cannot significantly improve the neurologicaldysfunction in rats.