甘氨酸对脑死亡大鼠供肝损伤的防护作用

The protection effects of glycine pretreatment on brain dead donor liver

目的探讨甘氨酸对脑死亡大鼠供肝损伤的防护作用。方法雄性Wistar大鼠42只,随机分为3组B组为脑死亡大鼠供肝移植组,G组为甘氨酸防护组,S组为士的宁拮抗组。3个组的供者均为脑死亡大鼠,在供者脑死亡模型建立后、供肝冷灌洗时和移植肝门静脉血流恢复时,G组分别给予0.6mmol、25μmol和25μmol的甘氨酸,S组除给予和G组同剂量的甘氨酸外,并给予士的宁(甘氨酸和士的宁浓度比为1000∶1),B组不作处理。测定供肝冷灌洗前、移植肝门静脉血流恢复后2h和6h时下腔静脉血中丙氨酸转氨酶、天冬氨酸转氨酶、透明质酸和肿瘤坏死因子α的水平,电镜观察移植肝门静脉血流恢复后6h的肝脏形态变化,原位末端标记法检测肝脏细胞凋亡情况。结果3个组除移植肝门静脉血流恢复后2h的透明质酸水平的差异无显著性外,其它指标在3个采血时间点的水平,G组均显著低于B组和S组(P<0.01),而B、S组间各项指标的差异无显著性;G组移植肝门静脉血流恢复6h的肝组织损伤明显轻于B、S组,Kupffer细胞的活化也不显著。结论甘氨酸能明显减轻脑死亡大鼠供肝的损伤。

Objective To evaluate the protection effects of glycine on the brain dead donor liver. Methods 42 male Wistar rats were randomized into 3 groups of liver transplantation: brain dead donor (BDD) group (group B), glycine pretreatment group with BDD (group G), strychnine pretreatment group with BDD (group S). For groups B, G and S, the brain death model was established in the donor rats and then liver transplantation was performed utilizing microsurgical techniques. After establishment of brain death state, and during liver cold rinse of donors or liver reperfusion of the recipients, rats in group B were treated with glycine at a dose of 0.6 mmol, 25 μmol and 25 μmol in group G, and rats in group S were given the same dose of glycine and strychnine ( 1 000 ∶1), and rats in group B were not treated. Before the cold rinse, at 2 h and 6 h after the portal vein (PV) reperfusion, blood samples were taken from IHVC to determine the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), tumor necrosis factor alpha (TNF α) and hyaluronic acid (HA). At 6 h after PV reperfusion, graft samples were fixed for morphological observation and the apoptosis of hepatocytes was detected by using TUNEL method. Results At the time points before liver cold rinse or at 2 h and 6 h after PV reperfusion, serum levels of ALT, AST, TNF α, HA and apoptosis index (AI) in groups B and S were significantly higher than those in group G ( P < 0.01 ). There was no significant difference between group B and S ( P > 0.05 ). Electron microscopy showed that Kupffer cells were activated and hepatic cells injured more obviously in groups B and S than in group G. Conclusion Glycine may alleviate the injury of the graft from the brain dead rats.