Coherent anti-stokes Raman scattering imaging of myelin degradation reveals a calcium-dependent pathway in lyso-PtdCho-induced demyelination
Coherent anti-stokes Raman scattering imaging of myelin degradation reveals a calcium-dependent pathway in lyso-PtdCho-induced demyelination
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DOI：
10.1002/jnr.21403
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发表时间：
2007-10-01
影响因子：
4.2
通讯作者：
Cheng, Ji-Xin
中科院分区：
文献类型：
--
作者：
Fu, Yan;Wang, Haifeng;Cheng, Ji-Xin
相干反斯托克斯拉曼散射（汽车）显微镜，它允许在其自然状态下的髓鞘振动成像，被施加到表征溶血磷脂酰胆碱（lyso-PtdCho）诱导的髓鞘降解在组织和体内。在离体脊髓组织或体内小鼠坐骨神经中注射lyso-PtdCho后，广泛观察到以汽车强度降低和兴奋极化依赖性丧失为特征的髓鞘肿胀。肿胀对应于通过电子显微镜观察到的髓鞘囊泡形成和分裂。脱髓鞘动力学通过从汽车图像测量的g比率的增加来量化。用离子载体A23187分裂的Ca-2处理脊髓组织导致与lyso-PtdCho相同的髓鞘降解。此外，脊髓组织与无Ca 2+的Krebs溶液或胞质磷脂酶A（2）（cPLA（2））抑制剂或钙蛋白酶抑制剂预孵育后，脱髓鞘病变的大小显著减小。与显像结果一致，在Krebs溶液中去除Ca ~（2+）或加入cPLA（2）抑制剂或calpain抑制剂可显著增加lyso-PtdCho处理的脊髓组织的平均复合动作电位幅度。我们的研究结果表明，lyso-PtdCho通过Ca-2诱导髓鞘降解，所述Ca-2通过流入髓鞘和随后的cPLA 2和钙蛋白酶的激活而被分开，所述cPLA 2和钙蛋白酶分解髓鞘脂质和蛋白质。目前的工作还表明，汽车显微镜是研究脱髓鞘的一个潜在的强大工具。(c)2007 Wiley-Liss，Inc.
Coherent anti-Stokes Raman scattering (CARS) microscopy, which allows vibrational imaging of myelin sheath in its natural state, was applied to characterize lysophosphatidylcholine (lyso-PtdCho)-induced myelin degradation in tissues and in vivo. After the injection of lyso-PtdCho into ex vivo spinal tissues or in vivo mouse sciatic nerves, myelin swelling characterized by the decrease of CARS intensity and loss of excitation polarization dependence was extensively observed. The swelling corresponds to myelin vesiculation and splitting observed by electron microscopy. The demyelination dynamics were quantified by the increase of g ratio measured from the CARS images. Treating spinal tissues with Ca-2 divided by ionophore A23187 resulted in the same kind of myelin degradation as lyso-PtdCho. Moreover, the demyelination lesion size was significantly reduced upon preincubation of the spinal tissue with Ca2+ free Krebs' solution or a cytosolic phospholipase A(2) (cPLA(2)) inhibitor or a calpain inhibitor. In accordance with the imaging results, removal of Ca2+ or addition of cPLA(2) inhibitor or calpain inhibitor in the Krebs' solution remarkably increased the mean compound action potential amplitude in lyso-PtdCho treated spinal tissues. Our results suggest that lyso-PtdCho induces myelin degradation via Ca-2 divided by influx into myelin and subsequent activation of cPLA2 and calpain, which break down the myelin lipids and proteins. The current work also shows that CARS microscopy is a potentially powerful tool for the study of demyelination. (c) 2007 Wiley-Liss, Inc.