The changes in brain water content and the effect of thrombin on brain edema after intracerebral hemorrhage in rats

Objective To investigate the changes in brain water content in rats and its relationship to thrombin following intracerebral hemorrhage (ICH). Methods Rats were divided randomly into a saline control group, an ICH group and a thrombin group. Autologous blood 50 μl, thrombin 5U and an equal volume of saline were separately injected into the right caudate nucleus in the corresponding rat groups. Brain edema was examined using the dry-wet weighing technique. For each experiment of different groups after certain intervals (4 h,12 h,24 h,48 h,72 h and 7 d) 6 rats were involved. Results The brain water content in ICH and thrombin groups was higher than in saline group at 4 h,12 h,24 h,48 h and 72 h(P0.05). Such differences were no longer noticed on 7day. The water contents at the given intervals were similar, showing no difference between the ICH group and the thrombin group(P0.05). Conclusion ICH may result in marked cerebral edema in an early stage (4 h) and its peak occurs at 24～48 h. The edema would start to go down after 3day, and the brain tissue would return to normal state after 7day. Thrombin might play important roles in brain edema formation after ICH.