细胞间粘附分子5（ICAM-5）在HIV相关神经损伤中的保护性作用

为探究细胞间粘附分子5 (intercellular adhesion molecule 5，ICAM-5)在HIV相关神经认知损伤中的作用,用ELISA法测定HIV感染者脑脊液样本和体外动物神经细胞培养体系中可溶性细胞间粘附分子5(ICAM-5s)的含量|蛋白印迹法检测ICAM-5蛋白表达|免疫荧光法观察神经细胞形态学变化|用CytoTox 96非放射性细胞毒性实验检测神经细胞死亡率.抗ICAM-5单克隆抗体Cy3标记的免疫荧光染色结果显示，ICAM-5可在神经元细胞的胞体和突起表达，且经HIV神经毒性蛋白gp120 500pmol/L处理的神经细胞平均突起长度显著小于无gp120处理的对照组|体外神经细胞培养体系中，gp120+基质金属蛋白酶3（MMP3）实验组的ICAM-5s含量显著高于gp120组，且前者神经元细胞的死亡率高于后者|在 HIV感染者中，HIV相关神经认知障碍（HIV associated neurocognitive disorder，HAND）患者脑脊液中ICAM 5s的水平显著高于认知功能正常的患者.结果表明,ICAM-5可能具有标记神经细胞突起的潜能，但其确切性有待进一步实验验证|ICAM-5与HIV相关神经认知功能损伤相关，具有潜在的神经元细胞保护作用.

The Protective Effct of Intercellular Adhesion Molecule-5 against HIV Associated Neural Impairment

To study the role of intercellular adhesion molecule-5（ICAM-5) in HIV associated neural impairment, the change of neurite length was evaluated by ICAM-5 immunofluorescence. The neuron death was analyzed by CytoTox 96Non-Radioactive Cytotoxicity assays. The concentrations of soluble ICAM-5 (ICAM-5s) in the CSF from HIV-infected patients, as well as in the in vitro cultural medium from neurobasal tissues, were detected by ELISA. The protein levels of ICAM-5 was assayed by Western blotting.The results showed that ICAM-5 expressed at both soma and neurite. The average neurite length was shorter in gp120 500pM treated neurons than that of gp120 negative controls. Higher cell motality and elevated levels of ICAM-5s was found with the addition of matrix metalloproteinases in the neurobasal medium than gp120 alone. In HIV-infected patients with neurocognitive impairment, ICAM-5s levels in the CSF was also higher than patients with normal cognition. Our results suggested that ICAM-5 potentially coud be used to label neurite，whether it is exact remains to be further confirmed. The expression of ICAM 5 in CSF might be correlated with HIV associated neurocognitive disorder, which could have the potential protective effect against neuronal cell.