Protective effect of fluid resuscitation with 6% hydroxyethyl starch 130/0.4 on the brain in a rat model of traumatic head injury complicated with hemorrhagic shock

Objective To investigate the protective effect of 6% hydroxyethyl starch (HES) 130/0.4 on the brain in a rat model of traumatic head injury (THI) complicated with hemorrhagic shock (HS) .Methods Sixty male SD rats weighing 300-350 g were randomized into 5 groups ( n - 12 each): group Ⅰ sham operation (group S);group Ⅱ THI-HS;group Ⅲ normal saline (group NS) ;group Ⅳ 6% HES 130/0.4 and group V HHS (1M mixture of 10% HES 130/0.4 + 7.5% NaCl) . The animals were anesthetized with intraperitoneal 10% chloral hydrate 4 ml/kg. Bilateral femoral arteries and right femoral vein were cannulated for MAP monitoring, blood letting and fluid resuscitation. In group Ⅱ-Ⅴ THI was produced according to the method described by Feeney. HS was induced by blood-letting (modified Wiggers Method) . MAP was reduced to 40 nun Hg which was maintained for 1 h. In group Ⅲ NS 3 times the volume of blood withdrawn was infused. In group Ⅳ 6% HES 130/0.4 equal to the volume of blood withdrawn was infused. Blood samples were taken before THI (T_0,baseline) , 60 min after THI-HS (T_1 ) and at 30, 60 and 180 min after fluid resuscitation (T_(2-4) ) for determination of serum S-100β protein concentration. Six animals in each group were killed at 3 h after resuscitation. Cerebral water and TNF-α and IL-6 contents were measured. Results MAP was restored to the baseline level immediately after resuscitation in group Ⅲ , Ⅳ and Ⅴ and was significantly higher in group Ⅳ(group HES) and Ⅴ (group HHS) than in group Ⅲ(group NS) . THI-HS significantly increased brain water content in group Ⅱ-Ⅴas compared with group I (group S) . Brain water content was significantly higher in the 3 resuscitation groups (group Ⅲ, Ⅳ, Ⅴ) than in group Ⅱ(THI-HS without resuscitation) . Resuscitation with NS induced higher brain water content than resuscitation with HES and HHS (group Ⅳ, Ⅴ). Serum S-100β concentration was increasing after THI-HS. The increase in serum S-100β concentration was attenuated by resuscitation with HES or HHS especially HES in group Ⅳ. The TNF-a and IL-6 contents in the brain tissue were significantly increased by THI-HS. Resuscitation with HES significantly attenuated the increase in TNF-α and IL-6 induced by THI-HS.Conclusion Resuscitation with 6% HES 130/0.4 can restore MAP and decrease brain edema induced by THI-HS by inhibition of inflammatory response. Key words: Brain injuries; Shock; hemorrhagic; Hetastarch; Fluid therapy