Laboratory of Membrane Biophysics and Macromolecules, Institute of Biochemistry and Biophysics, University of Tehran, PO Box 13145-1384, Tehran, Iran.
J Membr Biol. 2013 Aug;246(8):613-9. doi: 10.1007/s00232-013-9574-3. Epub 2013 Jun 23.
Immediate membrane sealing after spinal cord injury (SCI) can prevent further degradation and result in ultimate functional recovery. It has been reported that polyethylene glycol (PEG) can repair membrane damage caused by mechanical insults to the spinal cord. Furthermore, membrane fluidity and its sealing process vary at different temperatures. Here, we have assessed the possible synergistic effects of PEG and temperature on the repair of neural membranes in an SCI model. The effects of PEGs (400, 1,000 and 2,000 Da) were studied at different temperatures (25, 37 and 40 °C) by means of compound action potential (CAP) recovery and a lactate dehydrogenase (LDH) assay. Isolated spinal cords were mounted in a double sucrose gap chamber, where the amplitude and area of CAPs were recorded after implementing injury, in the presence and absence of PEG. Moreover, the LDH assay was used to assess the effects of PEG on membrane resealing. Data showed that the least CAP recovery occurred at 25 °C, followed by 37 and 40 °C, in all treated groups. Moreover, maximum CAP amplitude recovery, 65.46 ± 5.04 %, was monitored in the presence of PEG400 at 40 °C, followed by 41.49 ± 2.41 % in PEG1000 and 37.36 ± 1.62 % in PEG2000. Furthermore, raising the temperature from 37 to 40 °C significantly increased CAP recovery in the PEG2000 group. Similar recovery patterns were obtained by CAP area measurements and LDH assay. The results suggest that application of low-molecular weight PEG (PEG400) in mild hyperthermia conditions (40 °C) provides the optimum condition for membrane sealing in SCI model.
脊髓损伤 (SCI) 后立即进行膜密封可以防止进一步的降解，并最终实现功能恢复。据报道，聚乙二醇 (PEG) 可以修复脊髓机械损伤引起的膜损伤。此外，膜流动性及其密封过程在不同温度下有所不同。在这里，我们评估了 PEG 和温度对 SCI 模型中神经膜修复的可能协同作用。通过复合动作电位 (CAP) 恢复和乳酸脱氢酶 (LDH) 测定，研究了不同温度 (25、37 和 40°C) 下 400、1000 和 2000 Da 的 PEG 的作用。将分离的脊髓安装在双蔗糖间隙室中，在存在和不存在 PEG 的情况下，在实施损伤后记录 CAP 的幅度和面积。此外，LDH 测定用于评估 PEG 对膜重封的影响。数据显示，在所有处理组中，25°C 时 CAP 恢复最少，其次是 37 和 40°C。此外，在 40°C 下 PEG400 存在时，监测到最大的 CAP 幅度恢复，为 65.46±5.04%，其次是 PEG1000 的 41.49±2.41%和 PEG2000 的 37.36±1.62%。此外，将温度从 37°C 升高到 40°C 显著增加了 PEG2000 组中的 CAP 恢复。通过 CAP 面积测量和 LDH 测定获得了相似的恢复模式。结果表明，在温和的热疗条件 (40°C) 下应用低分子量 PEG (PEG400) 为 SCI 模型中的膜密封提供了最佳条件。
