目的:本研究的目的是阐明酪氨酸激酶受体B的特异性激动剂LM22A-4的保护作用及其潜在机制。脊髓损伤(SCI)。
方法:通过四层T7-T11椎板切除术将血管夹应用于小鼠的硬脑膜引起脊髓损伤。受伤后30分钟,提供LM22A-4的腹腔注射(剂量为10mg/kg和15mg/kg)或等体积的溶剂.SCI后24小时,进行Western印迹以检查p-TrkB的表达,p-Akt,p-ERK,cleaved-caspase-3和Bcl-2;进行TUNEL测定和Nissl染色以研究细胞凋亡和神经元存活。此外,在SCI治疗后,允许另一批小鼠存活14天,在此期间,每天在同一时间提供LM22A-4,并评估神经功能.
结果:小鼠脊髓损伤导致以组织损伤和细胞凋亡为特征的严重创伤。与载体处理组相比,用LM22A-4(10mg/kg)处理小鼠显著降低组织损伤程度(组织学评分)和细胞凋亡(TUNEL染色和caspase-3和Bcl-2表达)(P<0.05)。在一组单独的实验中,LM22A-4的慢性治疗也显著改善了肢体功能的恢复(P<0.05)。
结论:这项研究提供了一个实验证据,表明LM22A-4减少了与脊髓创伤相关的组织损伤的发展,和激活TrkB的活性可能代表了治疗脊髓创伤的新方法。
OBJECTIVE: The goal of this study was to elucidate the protection by and potential mechanisms of LM22A-4, a specific agonist of tyrosine kinase receptor B, against spinal cord injury (SCI).
METHODS: Spinal cord trauma was induced by the application of vascular clips to the dura of mice via a four-level T7-T11 laminectomy. Thirty minutes after the injury, an abdominal injection of LM22A-4 (at dosages of 10 mg/kg and 15 mg/kg) or an equal volume of solvent was provided. Twenty-four hours after SCI, a Western blot was performed to examine the expression of p-TrkB, p-Akt, p-ERK, cleaved-caspase-3, and Bcl-2; a TUNEL assay and Nissl staining were performed to study apoptosis and the survival of neurons. In addition, another batch of mice was allowed to live for 14 days after the SCI treatment, during which the LM22A-4 was provided at the same time each day and the neurological function was assessed.
RESULTS: Spinal cord injury in mice resulted in severe trauma characterized by tissue damage and apoptosis. Treatment of the mice with LM22A-4 (10 mg/kg) significantly reduced the degree of tissue injury (histological score) and apoptosis (TUNEL staining and caspase-3 and Bcl-2 expression) compared with vehicle treated group (P < 0.05). In a separate set of experiments, chronic treatment with LM22A-4 also significantly ameliorated the recovery of limb function (P < 0.05).
CONCLUSIONS: This study provides an experimental evidence that LM22A-4 reduces the development of tissue injury associated with spinal cord trauma, and activation of the activity of TrkB may represent a novel approach for the therapy of spinal cord trauma.