The effects of blood or plasma clot on brain edema in the rat with intracerebral hemorrhage.

The causes and characteristics of the brain edema which forms adjacent to an acute intracerebral hemorrhage (ICH) have not been explored thoroughly. This study was designed to examine the edema process in rat brain provoked by two different blood clot components. An intracerebral clot was produced by stereotactic injection of 100 microl of either blood (bICH) or cryoprecipitate/thrombin (pICH) into the right caudate nucleus. Water, Na+, K+, and Cl- contents were measured at 0, 4.24, 48, and 72 h after instillation of the clot. During the first 24 h, the water content of the ipsilateral caudate nucleus and cortex gradually increased in both groups. By 48 h brain edema was more severe in the bICH compared to that with pICH in the ipsilateral basal ganglia and cortex. The edema formation was accompanied by significant increase in sodium and chloride, as well as a decrease in potassium content by 48 h and sustained to 72 h. These results suggest that both blood and plasma clots can cause brain edema, but a plasma clot is less damaging than a blood clot in the immediate vicinity of the mass.