脑老化及阿尔茨海默病患者脑中星形胶质细胞及小胶质细胞改变的观察

目的观察人脑老化及阿尔茨海默病(Alzheimer’sdisease,AD)患者脑中星形胶质细胞与小胶质细胞形态的改变。方法应用胶质纤维酸性蛋白(glialfibrillaryacidicprotein,GFAP)及铁蛋白免疫组织化学方法,观察28例正常增龄病例(分为老年组和对照组)尸检脑标本额叶、枕叶、壳核、海马及6例AD病例(AD组)海马标本中星形胶质细胞与小胶质细胞的分布及形态学改变。结果铁蛋白免疫组织化学方法能够清晰地显示石蜡切片中的小胶质细胞。对照组患者GFAP阳性星形胶质细胞主要分布于白质,铁蛋白阳性小胶质细胞主要分布于灰质。老年组患者星形胶质细胞呈不同程度增生、肥大,小胶质细胞出现增生、活化,部分出现老年斑的正常老龄脑皮质中可见活化小胶质细胞聚集成团。个别病例小血管内外均见到活化小胶质细胞。结论星形胶质细胞及小胶质细胞增生、活化是脑老化的重要形态学改变,活化小胶质细胞有可能参与了老年斑的形成。

Morphological changes of astrocyte and microglia during aging and in patients with Alzheimer''''s disease

Objective To observe morphological changes of astrocyte and microglia during aging and in patients with Alzheimer's disease.Methods Twenty-eight brains of subjects (23～100 years of age) who died without clinical or pathological involvement of nervous system and 6 brains of Alzheimer's disease (AD) patients were obtained at autopsy.Glial fibrillary acidic protein (GFAP) and ferritin immunostaining methods were applied to sections from frontal lobe, occipital lobe, putamen and hippocampus of normal subjects and sections from hippocampus of AD patients to observe distribution and morphological changes of astrocytes and microglial cells.Results GFAP-positive astrocytes mainly distributed in white matter of brain in adults,while ferritin-positive microglial cells generally scattered throughout the gray matter. Proliferation and activation of astrocyte and microglia were obvious during brain aging. Clustered microglial cells were found in cortices of aged brains with β-amyloid deposition.Conclusions Proliferation and activation of astrocyte and microglia are important morphological changes during aging. Activated microglia may participate in the formation of senile plaque.