Effect Of Increase In Plasma Colloid Osmotic Pressureon Cerebral Edema Of Ischemia-reperfusion Rats

Objective:To investigate the effect of albumin and hydroxyethyl starch 130/0.4 on colloidal osmotic pressure, intracranial pressure, brain water content and cerebral neuron apoptosis of intracranial hypertension in rats caused by Cerebral Ischemia and reperfusion.Materials and Methods:The 32 male SD rats were divided into sham operation group, model group,albumin group and hydroxyethyl starch group, n=8.Cerebral Ischemia-reperfusion model was induced by middle cerebral artery occlusion (MCAO), then reperfusion after ischemia 2h and received hydroxyethyl starch and 10% albumin via tail vein at the beginning of reperfusion. The colloidal osmotic pressure (COP) and intracranial pressure were evaluated at 0,2,6,12,18,24h after surgeryed. The rats were killed by decapitation then were taken out to measure the right hemisphere water content and amount the apoptosis ratio of neurons by Immunohistochemical method after administration,.Results:At 2h after surgeryand the intracranial Pressure (ICP mmHg,1 mmHg= 0.133kPa) of hydroxyethyl starch group and model group significantly increased compared with sham group (model group ICP2h=11.500mmHg,hydroxyethyl starch group ICP2h=12.5mmHg,sham groupICP2h=7.950mmHg, <0.05); With time,the ICP gradually increased and reached the peak after 24h; But the ICP had no significant difference in the hydroxyethyl starch group compared with the model group at all time points (model group ICP24h=23.325mmHg,hydroxyethyl starch group ICP24h=22.763mmHg,sham groupICP24h=8.150mmHg, P<0.05). The COP(mmHg) of hydroxyethyl starch group after surgery had no significant difference in the hydroxyethyl starch group compared with the model group and sham group, but itwas significantly higher than the model group and sham group at each time point after 2h; and had no significant difference in the model group compared with the sham group at all time points (Peaked at 6h after surgery, hydroxyethyl starch group COP6h=13.488mmHg,model group COP6h=12.038mmHg,sham group COP6h=12mmHg, P<0.05). The brain water content, neuronal apoptosis of hydroxyethyl starch group and model group was significantly higher than sham operation group[brain water content:hydroxyethyl starch group BWC=80.161%,model group BWC=80.589%,sham operation group BWC=78.72%; the ratio of neuronal apoptosis:hydroxyethyl starch group=44.271%,model group=42.817%,sham operation group=3.256%, P<0.01],but has no significant difference between the hydroxyethyl starch group and model group (p>0.05)Conclusions:1,Through this experiment, we observed that whether natural colloidal - albumin, or synthetic colloids - hydroxyethyl starch can effectively increase the plasma colloid osmotic pressure, but we did not observe increased intracranial pressure and cerebral edema were reduced.2,It has not improved on neuronal apoptosis that to increase the plasma colloid osmotic pressure.3,Whether it has dose-effect relationship between the colloid osmotic pressure and intracranial pressure,the safe range of regulation of colloid osmotic pressure,whether it can decrease the intracranial pressure and reduce cerebral edema that regulation of plasma colloid osmotic pressure pending further study.