阿尔茨海默病患者血小板脂质筏内神经节苷脂GM1含量的研究

目的研究阿尔茨海默病(AD)患者血小板脂质筏内神经节苷脂GM1含量的变化,寻求一种可能作为辅助诊断AD的早期生物学指标。方法选择42例AD患者和45例认知功能正常的健康对照者分别进行神经功能评定,采用以Optiprep为介质的密度梯度离心方法分离血小板脂质筏,应用点印迹的方法进行鉴定后,采用BCA法测定血小板脂质筏内蛋白含量,比色法及点印迹定量分析法测定其内神经节苷脂GM1含量。结果在离心管25%~30%Optiprep溶液界面处可见一条白色的闪亮环带,经点印迹法证实,位于第6层的此白色闪亮环带即为脂质筏。AD组血小板脂质筏内蛋白含量略高于对照组,但差异无统计学意义(P=0.1494)。AD组血小板脂质筏内神经节苷脂GM1含量明显高于对照组,差异有统计学意义(P0.01),但其与年龄、MMSE评分无相关性。结论 AD组患者血小板脂质筏内神经节苷脂GM1含量与对照组相比明显升高,故血小板脂质筏内神经节苷脂GM1含量的改变在AD的诊断中有一定的潜在价值,有望成为一种辅助诊断AD的早期生物学指标。

Study on the ganglioside GM1 content of lipid rafts in platelets of patients with Alzheimer's disease

Objective To investigate the changes of ganglioside GM1 of lipid raft in platelets in patients with Alzheimer's disease (AD),in order to find an early biomarker for diagnosis of AD.Methods The neurological functions of 42 patients with AD and 45 subjects with normal cognition were evaluated by neuropsychological examinations.Lipid raft was isolated by Optiprep gradient centrifugation and identified by dot blotting.The protein content was measured by using BCA assay,ganglioside GM1 content using colorimetry and dot blotting analysis.Results A white light-scattering band under light illumination located at interface between 25%～30% Optiprep was detectable,which was revealed by dot-blotting.The lipid raft fraction floats within Optiprep gradient fraction 6.The platelet lever of protein in lipid raft was slightly higher in AD group than that in the control group,but there was no statistically significant difference between the two groups (P=0.1494).The platelet lever of ganglioside GM1 in lipid raft was statistically significantly higher in the AD group than that in the control group (P<0.01),but it was not significantly correlated with the age and the scores of MMSE.Conclusion As compared with normal mental state control,the ganglioside GM1 in lipid raft of the platelets in AD group was significantly increased,which may be associated with AD.The altered ganglioside GM1 in lipid raft of the platelets,probably an early biomarker of AD,is of potential value in clinical diagnosis of AD.