干旱区生态环境知识资源中心

Paraffin sections from the hippocampus of 12 head-injured patients (Group A, aged between 4 and 12 years n = 6 and Group B, aged between 64 and 89 years n = 6) and associated age-matched controls were stained by the terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphate nick end labeling (TUNEL) technique for evidence of in-situ DNA fragmentation. TUNEL+ cells were of 2 Types: I (non-apoptotic) and 11 (apoptotic). In addition sections stained H&E, combined Luxol Fast Blue/Cresyl Violet and by immunohistochemistry for astrocytes (GFAP) and macrophages (CD68) were used to characterize the lesions. Small numbers of Type I TUNEL+ cells were seen in all sectors of the hippocampus except CA2 of both Groups A and B. Type 11 TUNEL+ cells were mainly found in the white matter. They constituted less than 1% of all TUNEL+ cells. There were similar or fewer TUNEL+ cells in the corresponding areas in the controls compared with the head-injured patients. However, in the dentate fascia and the CA4 sector of the Group B cases, larger numbers of TUNEL+ cells were seen in controls than after trauma. In the grey matter most TUNEL+ cells had the morphology of necrosis that corresponded with foci of selective neuronal damage. Only a few TUNEL+ cells were seen in white matter. The occasional Type I TUNEL+ cells were seen in grey matter. It is concluded that the amount arid distribution of DNA fragmentation in children and adults is Similar and therefore at least in the hippocampus does not provide an explanation for age as an independent variable of outcome after traumatic brain injury in childhood.