急性肝衰竭小鼠血脑屏障结构和水通道蛋白4变化的研究

Changes of blood-brain barrier structure and aquaporin 4 in mice with acute liver failure

目的观察急性肝衰竭小鼠脑水肿时血脑屏障结构和脑组织水通道蛋白4(AQP4)的改变。方法本实验于2016年1—12月在武汉大学人民医院中心实验室进行实验,共纳入SPF级C57BL/6小鼠30只,随机数字表法分为模型组和对照组各15只,模型组采用脂多糖及D-氨基半乳糖联合诱导小鼠急性肝衰竭模型,对照组腹腔注射等量生理盐水。24 h后观察小鼠肝组织变化检测血清ALT、AST、血氨水平,血脑屏障结构和脑组织水通道蛋白4的表达水平。结果模型组出现明显病理性肝组织损害,对照组无显著变化;与对照组比较,模型组血清ALT、AST和血氨水平显著升高(t=5.075、6.338、5.718,P<0.05)。模型组脑组织血脑屏障结构轻度异常,电镜下可观察到微血管周围星形胶质细胞足突明显肿胀、内皮细胞出现大量囊泡和液泡,内皮细胞紧密连接打开。脑组织AQP4蛋白表达水平与对照组比较差异无统计学意义(t=-0.961,P=0.397)。结论急性肝衰竭脑水肿时血脑屏障结构存在轻微改变,血管源性水肿机制参与急性肝衰竭脑水肿,但脑组织中AQP4蛋白水平未出现明显改变。

Objective To observe the changes of blood-brain barrier structure and aquaporin 4（AQP4） in brain edema of mice with acute hepatic failure.Methods All male C57BL/6 mice were divided into control and model group.The ALF experimental animal models were induced by a combination of lipopolysaccharide（LPS） and D galactosamine（D Gal）.The BBB of integrity was assessed by transmission electron microscope.Liver histologic analysis was performed,the brain protein of AQP4,and levels of alanine aminotransferase（ALT）,aspartate aminotransferase（AST）,serum ammonia were observed.Results The model group had obvious pathological liver tissue damage,but there was no significant change in the control group.Compared with the control group,the serum ALT,AST and serum ammonia levels in the model group increased significantly（t=5.075,t=6.338,t=5.718,P0.05）.The model group of brain blood brain barrier structure was abnormal,can be observed by electron microscopy and micro blood vessels around the astrocyte swelling,endothelial cells appeared large vesicles and vacuoles,endothelial cell tight junction opened.The expression level of AQP4 protein in brain tissue was not significantly different from that in control group（t=-0.961,P=0.397）.Conclusion There is a slight change in the blood-brain barrier structure in patients with acute hepatic failure with cerebral edema.The mechanism of vascular edema is involved in the brain edema of acute hepatic failure,and the level of AQP4 protein in brain tissue has not changed significantly.