Measuring the accentuation of the brain damage that arises from perinatal cerebral hypoxia-ischemia

To ascertain the manner in which the severity of perinatal brain damage occurs as a result of hypoxia-ischemia, 7-day postnatal rats were subjected to unilateral common carotid artery ligation followed thereafter by exposure to 8% oxygen for up to 2.5 h. Following the hypoxic-ischemic exposure, the rat pups were reared with their dams until 30 days of postnatal age, at which time their brains underwent pathologic analysis. The severity of brain damage at each of four specific intervals of hypoxia-ischemia was determined and statistically compared by linear polynomial and nonparametric regression procedures. The data indicated that the accentuation of brain damage with increasing duration of hypoxia-ischemia was linear rather than curvilinear.