Brain changes in experimental chronic hypoxia

A model of normobaric hypoxia was developed in which adult female cats were exposed to decreasing amounts of oxygen (21, 15, 10, 8, 7, and 5 vol.%) over a period of 320 days. Blood flow as well as the blood flow responses to changes of pCO2 were depressed in both cerebrum and cerebellum. These decreases were more severe in the cerebellum. The metabolic rate for oxygen was also depressed. A decrease in the Purkinje cell number was evident. A different degree of damage was observed in the top, the intermediate and the bottom region of the cerebellar gyri. Microvascular proliferation occurred in the whole brain.