Distribution of platelet-derived growth factor-alpha receptor expressing oligodendrocyte precursor cells in the adult rat brain

摘要

BACKGROUND: Studies have demonstrated that NG2-positive glial cells in the adult rats arepredominantly located in the gray and white matter of the cerebral cortex and hippocampus.Platelet-derived growth factor-α receptor (PDGF-αR) cells are a subset of oligodendrocytes, whichare not as mature as NG2-positive cells. Distribution and migration of PDGF-αR-positive cells in therat brain remain poorly understood.OBJECTIVE: Using immunohistochemical methods, the distribution of oligodendrocyte precursorcells (PDGF-αR-positive) was analyzed in the adult rat brain.DESIGN, TIME AND SETTING: Immunohistochemical study was performed at the Department ofHistology and Embryology of the Third Military Medical University from September 2007 toSeptember 2008.MATERIALS: Rabbit anti-PDGF-αR polyclonal antibody was purchased from Santa CruzBiotechnology, USA. Streptomycin-avidin-biotin complex immunohistochemistry kit was purchasedfrom Zhongshan Goldenbridge Biotechnology, China.METHODS: Whole brains from 5 healthy, adult, Wistar rats were collected for immunohistochemistryand the mean value of PDGF-αR-expressing cells was quantified. The absolute values weretranslated to ranked data of high, moderate, and low grades (high grade: 10 positive cells; moderategrade: 5-9 cells; low grade: < 5 cells in a 400 x visual field). Based on the number of cell processesand branches, as well as the number of PDGF-αR-positive cells, in different regions, the cells wereclassified into three categories, i.e., type Ⅰ-Ⅲ. From type Ⅰ to type Ⅲ, the number of processesgradually increased.MAIN OUTCOME MEARSURES: The number and distribution of PDGF-αR-positive cells in differentbrain regions of adult rats.RESULTS: PDGF-αR-positive cells were located in the forebrain and midbrain, but not in thecerebellum or brainstem. In the olfactory bulb and hippocampus, a total of 60% PDGF-αR-positivecells were type I and these cells were not mature as others. In the cerebral cortex, olfactory system,hippocampus, and optic chiasma, where neuronal bodies aggregated, approximately 40% of thePDGF-αR-positive cells were type Ⅱ, with few type Ⅲ cells. In the white matter, corpus callosum,basal nucleus, and thalamus, PDGF-αR-positive cell density was moderate. In the olfactory bulb andhippocampus, PDGF-αR-positive cell density was high. PDGF-αR-positive cells were not observedin the cerebellum or brainstemCONCLUSION: PDGF-αR-positive cells were aggregated in the olfactory bulb and hippocampus inthe adult, rat brain, but few cells were detected in the cerebellum and brainstem.