大鼠小肠移植物热缺血时限的研究

随着小肠移植手术技术的不断完善和排斥反应的逐步控制、小肠移植物的供需矛盾日益突出。扩大供体来源、解决移植物的供需矛盾是移植领域的新课题，于是对无心跳供体来源移植物的研究成为国内外关注的热点，尤其在我国无心跳供体是临床器官移植中移植物获取的主要途径。在无心跳供体来源移植物获取过程中存在着热缺血过程，热缺血时限的确定将对临床器官移植中移植物的获取时限提供参考。     

核因子-κB在白细胞介导大鼠移植胰腺缺血再灌注损伤中的作用

目的 探讨核因子(NF)-κB在大鼠移植胰腺再灌注损伤中的作用及其可能机制.方法 应用同系大鼠异位全胰十二指肠移植模型,大鼠移植术前和术后5 min静脉注射NF-κB抑制剂脯氨酸二硫代氨基甲酸酯(ProDTC)(15 mg/kg),移植术后24 h经腹主动脉取血测定大鼠血清肿瘤坏死因子(TNF)-α、巨噬细胞炎性蛋白(MIP)-2浓度酶联免疫吸附试验(ELISA)、血糖、淀粉酶、脂肪酶水平.测定胰腺组织NF-κB p65蛋白含量(Western blot)、TNF-α mRNA、MIP-2 mRNA、细胞间黏附分子(ICAM)-1 mRNA表达逆转录-聚合酶链反应(RT-PCR)、髓过氧化物酶(MPO)活性.并进行组织学观察.结果 移植后24 h ProDTC组和对照组血清中TNF-α、MIP-2水平、胰腺组织中NF-κB p65蛋白含量、TNF-α mRNA、MIP-2 mRNA、ICAM-1 mRNA表达、MPO活性均升高,而ProDTC组水平明显低于对照组(P<0.05).移植后24 h血糖、脂肪酶水平在PmDTC组[(9.1±2.8)mmoL/L,(192±26)U/L]明显低于对照组[(13.0±3.1)mmol/L,(297±31)U/L,P<0.05].ProDTC组胰小叶间质水肿和胰小叶内中性粒细胞浸润较轻.结论 移植胰腺缺血再灌注后,NF-κB活化上调了TNF-α、MIP-2、ICAM-1表达从而增加中性粒细胞浸润,外源性应用NF-κB抑制剂ProDTC可以减轻移植胰腺缺血再灌注损伤.     

Liver injury following renal ischemia reperfusion in rats

Introduction

All transplanted solid organs experience some degree of ischemia-reperfusion (I-R) injury. There is some evidence that I-R injury affects remote organs. We investigated the effects of renal I-R injury on hepatic function, cytochrome P-450 enzymes, and morphology in rats.

Methods

A rat model of 1 hour of renal ischemia followed by 1, 4, or 8 hours of reperfusion. The assays included serum alanine aminotransferase (sALT) aspartate aminotransferase (sAST), cytochrome P-450 enzymes (CYP3A, CYP2E1), hepatic glutathione S-transferase (GST), glutathione (GSH), malondialdehyde (MDA), superoxide dysmutase (SOD), and myeloperoxidase (MPO) activities. In addition, we measured serum blood urea nitrogen (BUN) and serum creatinine (SCr), and renal MDA, glutathione peroxidase levels, and SOD activities. Morphological liver changes were observed by optical and electron microscopy.

Results

sALT and sAST significantly increased after 1 hour of ischemia and 4 or 8 hours of reperfusion. Hepatic CYP3A and CYP2E1 activities were significantly decreased after 1 hour of ischemia and 1 or 4 hours of reperfusion. Hepatic GST, GSH, and SOD activities decreased after renal I-R, while MDA levels and MPO increased. Serum BUN and SCr levels significantly increased after reperfusion. Changes in renal MDA, GSH-px, and SOD activities were similar to those in the liver. The only difference between them was the peak time of injury: for the kidney, 8 hours, while for the liver, some changes appeared at 4 hours. Optical microscopy showed hepatic passive venous congestion and fatty degeneration as well as local necrosis. Transmission electronic microscope showed hepatic cell membrane was damaged, which seemed to explain some data results above. For example, the release of hepatic ALT and AST increased serum ALT and AST. More importantly, the release of neutrophil chemokine induced neutrophil accumulation in the liver, which could cause further damage.

Conclusion

Our findings indicated that hepatic function, cytochrome P-450 enzymes and morphology were affected by renal I-R injury. These effects seemed to be mediated in part by an imbalance of oxidant and antioxidant systems and recruitment of neutrophils to the liver.     

心磷脂与缺血/再灌注损伤

心磷脂（CL）是维持线粒体能量代谢所必需的一种磷脂，参与了众多重要生理过程。此文对CL的结构、合成和转化；在维持线粒体正常功能中的作用；缺血／再灌注（I／R）损伤中的改变以及和线粒体功能的关系等作了逐一阐述，说明CL与I／R损伤导致的细胞死亡关系密切，CL量或性质的改变在细胞凋亡中处于中心地位。     

谷氨酰胺强化肠外营养对大鼠小肠黏膜缺血再灌注损伤的影响

目的：构建大鼠小肠缺血再灌注模型,观察谷氨酰胺强化肠外营养对小肠黏膜屏障作用的影响,并探讨其作用机制。方法：30只雌性Wistar大鼠,随机分为正常对照组（N组）、传统肠外营养组（TPN组）和谷氨酰胺强化肠外营养组（TPN＋Gln组）3组,每组10只。TPN组和TPN＋Gln组构建小肠缺血再灌注模型后予完全肠外营养5d。观察3组小肠黏膜形态、血浆D-乳酸、内毒素、TNF-α、IL-6水平及小肠黏膜HO-1 mRNA和蛋白的表达。结果：TPN＋Gln组与TPN组相比,小肠黏膜组织形态明显改善,血浆D-乳酸、内毒素、TNF-α和IL-6水平均显著性降低,HO-1 mRNA及蛋白表达水平明显增高。结论：谷氨酰胺强化肠外营养可以明显减轻大鼠缺血再灌注小肠黏膜屏障损伤及炎性反应,保护黏膜屏障完整性,并促进HO-1 mRNA表达及HO-1合成。HO-1及其代谢产物的抗氧化、抗凋亡及抗炎作用可能是谷氨酰胺保护缺血再灌注损伤小肠的作用机制。