垂体腺苷环化酶激活多肽抑制β淀粉样蛋白对Neuro-2a细胞神经毒性作用的机制

Pituitary adenylate cyclase activating polypeptide protects neuro-2a cells from βamyloid protein cytotoxicity by modulating intracellular calcium

通过MTT方法检测细胞活性 ,同时采用激光共聚焦显微镜技术检测细胞内游离钙离子的瞬时运动 ,研究了垂体腺苷环化酶激活多肽 (pituitaryadenylatecyclaseactivatingpolypeptide 2 7,PACAP2 7)通过调节细胞内钙对抗淀粉样蛋白Aβ2 5 35引起Neuro 2a细胞神经毒性作用的可能机制。结果表明 ,PACAP在一定浓度范围内 (<0 1μmol/L)可提高Neuro 2a细胞增殖能力并对抗Aβ引起的神经毒性 ,此作用可以被PACAP受体竞争性拮抗剂PACAP6 2 7所抑制。 2 5 μmol/LAβ使细胞内钙离子缓慢上升 ,并有一个较长时间的平台期。 0 1μmol/L的PACAP使细胞内钙离子迅速升高后下降 ,10min后回到接近基线水平 ,伴有较长时间的不应期。用PACAP预处理细胞 10min后Aβ引起细胞内钙的慢上升不再出现。推测 ,PACAP受体激活引起瞬时内向钙离子运动 ,而后伴随一个较长时间的不应期 ,可能是一个消除凋亡或阻止凋亡启动的保护机制。

MTT analysis and intracellular calcium measurement by using confocal laser scanning microscopy were used to study the possible mechanism of protective effect of pituitary adenylate cyclase activating polypeptide 27 (PACAP27) from β amyloid protein (Aβ) induced neurotoxicity. The results showed that treatment with PACAP (less than 0 1 μmol/L) increased the survival and reproductive ability of neuro 2a cells and protected the neuro 2a cells from being injured by Aβ. The protective effect of PACAP27 was reversed by the competitive PACAP receptor antagonist PACAP6 27. An increase in intracellular calcium was observed when the cells were challenged with Aβ and PACAP. But the calcium increase induced by Aβ kept stable for a long time while PACAP caused a transient rise in intracellular calcium. The intracellular calcium increase induced by Aβ was blocked by pretreatment with PACAP for 10 min. It is suggested that the neuroprotective effect of PACAP against neuronal damage induced by Aβ may result from its role in inhibiting the sustained rise in intracellular calcium.