Prostacyclin reduces early ischemic changes in central nervous system

The authors made a study of the effect of prostacyclin (PGI2) on ischemic morphological changes in the brain, extracellular calcium concentration (Ca2+e) and the blood-brain barrier (BBB) permeability. This was combined with physiological and neurophysiological measurements. Complete cerebral ischemia (CCI) lasting 15 or 20 min was produced by the ligation of the brachiocephalic trunk, the left subclavian and both internal thoracic arteries. The experiments with PGI2 were carried out in two groups. In group I, the rabbits received PGI2 3 min before CCI, during it and for 15 min after it. In group II PGI2 was infused in the last 3 min of CCI and for 40 min after it. Control animals with CCI of the same duration were not given PGI2 medication. The rabbits treated with PGI2 were found to have recovery of the bioelectric activity of the brain in half the time that its return took in the untreated cases. PGI2 was noted to have a positive effect on some parameters of the peripheral blood system after CCI. Application of PGI2 reduced the depth of ischemia-evoked drop of Ca2+e by 50% without accelerating recovery during recirculation; the post-ischemic increase of BBB permeability to fluorescein was also diminished. PGI2 reduced edema and the spectrum of neuronal changes and decreased the number of pathologically changed neurons in the brain. In the group that received PGI2 ischemic ultrastructural changes in the cytoplasm of neurons were abolished, but PGI2 did not prevent pathological changes in the neuronal nuclei after CCI. Those changes were manifested in numerous vesicular structures and nuclear inclusions.(ABSTRACT TRUNCATED AT 250 WORDS)