Beagle puppy model of intraventricular hemorrhage. Effect of superoxide dismutase on cerebral blood flow and prostaglandins.

Intraventricular hemorrhage (IVH) represents a major problem for preterm neonates and is thought to occur secondary to alterations in cerebral blood flow (CBF) to damaged germinal matrix tissues. Many investigators believe that both local CBF and changes in capillary morphology and permeability may be partially controlled by prostaglandins. To evaluate this hypothesis, the authors have studied the effects of superoxide dismutase (SOD), a known free-radical scavenger, on newborn beagle pups that were randomly assigned by computer to four groups consisting of either SOD- or saline-pretreated animals that underwent either insult by hemorrhagic hypotension/volume reexpansion or no insult. Prostaglandin levels were determined prior to and 60 minutes following the administration of the solutions, and carbon-14 iodoantipyrine autoradiography was performed for determination of CBF. It was demonstrated that, although SOD significantly decreased the incidence of IVH in this model (p less than 0.05), it caused no alterations in baseline CBF or prostaglandin levels. In addition, SOD did not prevent either the systemic blood pressure changes or the alterations in CBF found in response to a hemorrhagic hypotensive insult. The authors propose that neonatal IVH results from a combination of factors, one of which is prostaglandin-mediated alterations in CBF to a damaged capillary matrix.