姜黄素体外抑制Aβ_(42)聚集和毒性作用及结合老年斑的研究

Curcumin inhibits aggregation of Aβ_(42), reduces neurotoxicity of Aβ_(42) and binds plaques in vitro

目的为了研究姜黄素对β-淀粉样多肽42(Aβ42)聚集和神经毒性的影响,以及姜黄素对阿尔茨海默病(AD)患者脑组织中老年斑的结合情况。方法通过硫磺素T(Th-T)荧光分析Aβ42蛋白体外聚集特点和姜黄素对Aβ42聚集的抑制作用;应用培养的SK-N-SH细胞、MTT法观察不同孵育时间的Aβ42神经毒性以及姜黄素对神经毒性的影响;利用姜黄素自发荧光特性观察其对AD病人海马组织石蜡切片中老年斑的结合作用。结果 Th-T荧光分析结果显示随着孵育时间的延长,Aβ42的荧光强度逐渐加强,在6 d时荧光强度明显增加(P<0.01),加入姜黄素(20μmol/L)能够显著降低Aβ42的荧光值;孵育时间超过0.5 d的Aβ42对SK-N-SH细胞均可产生毒性作用,细胞存活率、细胞突起和长度均减小。而经姜黄素(20μmol/L)治疗后,SK-N SH细胞存活率明显升高,细胞突起增多、变长;姜黄素还能够特异性标记AD病人海马组织中Aβ40/42抗体免疫阳性和免疫阴性老年斑。结论姜黄素能够有效抑制Aβ42体外聚集,并减小其神经毒性。在AD病人海马组织切片上,姜黄素能够特异性结合AD病人脑中沉积的老年斑,具有比抗体更广泛的老年斑结合能力。上述结果提示姜黄素有可能成为阻止AD发生和阻断疾病进展的治疗性药物。

Objective To investigate effects of curcumin on aggregation and neurotoxicity of β-amyloid42(Aβ42), and examine whether curcumin could bind plaques on brain tissue of AD patients. Methods We observed the self-aggregation of Aβ42and the inhibitory effect of curcumin by using thioflavine-T fluorometric assay; We examined the neurotoxicity of Aβ42and protective effect of curcumin in cultured SK-N-SH cells by MTT assay. We futher characterized curcumin labeling of senile plaques on paraffin sections of hippocampal tissue of AD patients. Results The data from thioflavine-T fluorometric assay showed that the fluorescence intensity of Aβ42increased with the incubated time, and at the 6th day the fluorescence intensity of Aβ42was significantly increased(P < 0.01). The fluorescence intensity of Aβ42reduced obviously after incubated with curcumin(20 μmol / L). The Aβ42(incubated more than 0.5 d) was neurotoxic, could reduce cell viability and neurites length of SK-NSH cell. The cell viability increased and cell morphologies were significantly improved after curcumin(20 μmol / L) treatment, including the number of neurites increased and neurite growth. Curcumin labeled not only Aβ positive senile plaques, but also Aβnegative senile plaques. Conclusion Curcumin could prevent Aβ42from polymerizing and forming fibril, and reduce the neurotoxicity in vitro. Curcumin has a better affinity protein amyloidosis than Aβ42antibody. These study suggested that curcumin could be considered as potential therapeutic agent of AD.