Effect of hydroxyethyl starch on intracranial pressure and plasma colloid osmotic pressure in rats with cerebral ischemia/reperfusion injury

Abstract

To investigate the regulatory effect of hydroxyethyl starch on colloidal osmotic pressure (COP), and its effect on intracranial pressure (ICP) in rats with cerebral ischemia/reperfusion (I/R) injury. Twenty four male Sprague Dawley (SD) rats were randomly divided into sham operation group, model group and the hydroxyethyl starch group, each n =8. Cerebral I/R model was reproduced by middle cerebral artery occlusion (MCAO), followed by reperfusion after ischemia for 2 hours. Rats in hydroxyethyl starch group received hydroxyethyl starch 130/0.4206 ml × kg(-1)× d(-1) ia tail vein at the beginning of reperfusion. ICP and COP were evaluated at 0, 2, 6, 12, 18, 24 hours after the surgery. The rats were sacrificed by decapitation. The water content of the right hemisphere was measured at 24 hours after the surgery, and the ratio of apoptosis of neurons was observed by immunohistochemical method. Two hours after surgery the ICP (mm Hg, 1 mm Hg=0.133 kPa) of model group and hydroxyethyl starch group was significantly increased compared with sham operation group (11.50 ± 1.43, 12.48 ± 0.75 vs. 7.95 ± 0.92, both P <0.05). With prolongation of time, the ICP gradually increased and reached the peak at 24 hours (22.76 ± 0.72, 23.32 ± 0.98 vs. 8.15 ± 1.09, both P <0.05). But there was no significant difference in ICP in the hydroxyethyl starch group compared with that of the model group at all time points. The COP (mm Hg) of hydroxyethyl starch group was significantly higher than the model group and sham operation group at each time point, and peaked at 6 hours after surgery (13.49 ± 0.50 vs. 12.04 ± 0.47, 12.00 ± 0.39, both P <0.01). There was no significant difference in COP between the model group and the sham operation group at all time points. The brain water content, neuronal apoptosis of hydroxyethyl starch group and model group was significantly higher than sham operation group [brain water content: (80.16 ± 0.44)%, (80.59 ± 0.67)% vs. (78.72 ± 0.52)%; neuronal apoptosis:(44.27 ± 7.86)%,(42.82 ± 7.82)%vs. (3.26 ± 0.00)%, P <0.05 or P <0.01], but there was no significant difference between the hydroxyethyl starch group and model group (both P >0.05). Intravenous injection of hydroxyethyl starch 130/0.4 can increase the plasma COP, but it can not significantly reduce ICP and brain water content, and it also can not improve the neuronal apoptosis.