Adverse biochemical and physiological effects of prostacyclin in experimental brain oedema

BACKGROUND: Prostacyclin (PGI2) and its stable analogues are known to reduce capillary hydraulic permeability. This study explores the biochemical and physiological effects of i.v. infusion of low-dose PGI2 in an experimental model of vasogenic brain oedema. METHODS: Twenty-seven anaesthetized and mechanically ventilated piglets with brain oedema induced by intrathecal injection of lipopolysaccharide (LPS) were used. Five of the animals received a continuous infusion of PGI2 (1 ng kg(-1) min(-1)) i.v. Four microdialysis catheters were placed in the brain to measure interstitial concentrations of glucose, lactate, and glycerol. Mean arterial pressure (MAP), intracranial pressure (ICP) and temperature were monitored continuously. Low-dose infusion of PGI2 started 1 h before the LPS injection and was constant during the study period. RESULTS: Intracranial pressure increased significantly in animals treated with PGI2. The increase in ICP was associated with significant cerebral biochemical changes: decrease in glucose, increase in lactate, increase in lactate/glucose ratio and increase in glycerol. CONCLUSION: In LPS-induced brain oedema i.v. infusion of low-dose PGI2 caused a further increase in ICP and a perturbation of energy metabolism, indicating cerebral ischemia and degradation of cellular membranes.