不同渗透浓度晶体液对失血性休克大鼠血脑屏障和脑水肿的影响

目的:比较3种不同渗透浓度晶体液对重度失血性休克大鼠血脑屏障(BBB)和脑水肿的影响。方法:雄性SD大鼠随机分成乳酸钠林格注射液(林格液)组、7.2%高渗氯化钠注射液(高渗盐)组和复方电解质注射液(复方电解质)组,每组50只,重度失血性休克放血量占全身血容量的40%,平均动脉压(MAP)为35~45mmHg]维持1 h后分别输入乳酸钠林格注射液、复方电解质注射液或7.2%高渗氯化钠注射液;测定放血前(T0)、放血1 h(T1)、输液毕即刻(T2)、1 h(T3)、2 h(T4)血清S100B含量、脑组织伊文思蓝(EB)含量和干/湿质量比,电镜观察海马CA1区BBB改变。结果:三组T1~T4时间点血清S100B含量均比T0时升高(P<0.05)。高渗盐和复方电解质组在T3和T4时显著低于林格液组(P<0.01)。放血及输液前后脑组织EB含量无变化(P>0.05)。与T0比较,林格液组T1~T4时间点脑组织含水量都显著增加(P<0.05),高渗盐组仅在T1时增加(P<0.05),复方电解质组在T1、T2和T3时增加(P<0.05)。三组脑组织含水量在T0和T1时无显著差异(P>0.05);T2时高渗盐组脑组织含水量低于林格液组(P<0.01);T3和T4时高渗盐和复方电解质组都低于林格液组(P<0.01)。放血1 h后电镜下示血脑屏障发生改变,林格液组胶质细胞足突空泡化最明显,毛细血管周围水肿液最多。结论:重度失血性休克后BBB通透性和脑组织含水量增加,乳酸钠林格注射液复苏时短期内加重BBB损伤和脑水肿,7.2%高渗氯化钠注射液和复方电解质注射液复苏都能减轻BBB损伤和脑水肿,且7.2%高渗氯化钠注射液优于复方电解质注射液。

Effects of different crystalloid fluids at different osmotic concentrations on blood-brain barrier and cerebral edema in hemorrhagic shock rats

Objective:To compare the effects of 3 different crystalloid fluids at different osmotic concentrations on blood-brain barrier(BBB) and brain edema in severe hemorrhagic shock rats.Methods: A total of 150 male SD rats were equally randomized into a lactated Ringers(LR) group,a 7.2% hypertonic saline(HS) group and a plasmalyte A(PA) group.LR,PA and HS were administered after an hour of severe hemorrhagic shock induced by drawing out about 40% of total blood and maintaining MAP at 35-45 mmHg.Serum S100B,cerebra1 Evans Blue(EB) and water content were determined before(T_0) and 1 h after bleeding(T_1) and immediately(T_2),1 h(T_3) and 2 h(T_4) after administration.The changes of BBB in the hippocampus CA1 area were observed by electron microscopy.Results: The serum S100B level was obviously higher at T_1,T_2,T_3 and T_4than at T_0 in all groups(P<0.05) and evidently lower s at T_3 and T_4 in the HS and PA than in the LR group(P<0.01),with no difference in the EB content among different time points(P>0.05).The cerebra1 water content was significantly increased at T_1,T_2,T_3 and T_4in the LR group,at T_1in the HS and at T_1,T_2 and T_3 in the PA as compared with T_0(P<0.05),but lower at T_2,T_3 and T_4in the HS and at T_3 and T_4in the PA than in the LR group at the same time point.Electron microscopic studies showed evident changes of BBB after a 1-hour hemorrhagic shock,most obviously the vacuolization of the glia cell foot process and severe brain edema in the LR group.Conclusion: Severe hemorrhagic shock induces BBB injury and cerebral edema,which could be aggravated by LR and alleviated by HS and PA,the former even more effectively than the latter.