OBJECTIVETo observe the distribution of hypoxia inducible factor-1alpha (HIF-1alpha) in different brain regions in aged rats and investigate the role of HIF-1alpha in the aging process of the nervous system.

METHODSThe Nissl bodies and HIF-1alpha expression in different brain regions were observed in rats aged 3 and 30 months using Nissl staining and immunohistochemical method, respectively.

RESULTSIn the 30-month-old rats, the neural cells in 4 different brain regions presented with large cell body and loose alignment, containing reduced Nissl bodies in the cytoplasm. Compared with the 3-month-old rats, the aged rats showed greater number of HIF-1alpha-positive cells in the brain (P < 0.01), and the number varied significantly between the different brain regions (P < 0.01). The CA3 region contained the greatest number of positive cells, which were fewer in the motor cortex and cerebellum.

CONCLUSIONThe capacity for protein synthesis in the neural cells is weakened but the expression of HIF-1alpha increased in aged rats, suggesting the important role that HIF-1alpha may play in the aging process of the nervous system, especially in hypomnesis.