The Effect Of Acceptor Hypoxic Preconditioning On Liver Transplanted Via Protecting Intestinal Barrier Function

【Objective】: This investigation builds on rats orthotopic liver transplantation(OLT) model. Acceptors administrate hypoxic preconditioning in preoperative 24h.Aim to investigate protection of hypoxic preconditioning on intestinal barrierfunction via quantitative analysis of serum endotoxin and observation of intestinalmucosa microstructure and ultrastructure. To compare liver transplantedpostoperative 2h both B group and A group including serum liver function,analysis of hepatic tissue MDA,SOD, IL-1and TNF-a mRNA expression and thechange of microstructure and ultrastructure.To find the relationship of intestinalmucosa barrier function and liver transplanted early-stage ischemia reperfusioninjury in order to provide a potential approach for clinic hepatic transplantation.【Method】: Adult male Sprague-Dawley (SD) rats were randomly divided into threegroups. A: OLT group (n-8), B: AHP (acceptor hypoxic preconditioning)--OLTgroup (n=8), C: Shame operation group(n=6). Group B, Acceptors were treatedwith 8% nitrogen oxygen atmosphere for 90 minutes by 5L/min flow rate inpreoperative 24hours. Rats orthotopic liver transplantation are according toKamada two-sleeve approach. The sham group was subjected to the surgicalprocedures without liver manipulation and maintained under anesthesia for thesame time. Two hours after the reperfusion, all animals underwent relaparotomythrough the previous incision. The abdominal aorta was punctured and bloodsamples were collected for measurement of plasma endotoxin levels, liverenzymes and serum total bilirubin (TBil). liver tissue samples from the left lobewere collected, washed with cold physiologic saline solution and immediatelyfrozen in -80℃refrigerator until malondialdehyde (MDA) levels, superoxide dismutase (SOD), IL-1βand TNF-a mRNA RT-PCR determination. Liver tissuesamples and ileal mucosal samples were biopsied, fixed in 2.5% glutaraldehydeand 10% formaldehyde for later histological study by electronic-microscopy andoptic-microscopy respectively. Twelve rats were left to observe the one weeksurvival rate.【Results】:1. The standard of stable OLT models is able to maintain steady respiration andheartbeat, revive and turn body over post-operation. Cold ischemic time,unhepatic period of OLT were controlled within 50±3.15min,20±2.15minrespectively. The difference of the operation and the conservation of the graftcould be neglected. The totle number of animal treated with orthotropic livertransplantation in group A and group B respectively is 20, of which 8 wasrandomly selected to obtain the samples with 12 left to observe the survival.The one week survival rate of group B,41.7% (5/12), was significantly longerthan group A—66.7% (8/12) (P＜0.01)..2. The ALT and AST in A group and B group is significantly higher than that ingroup C, P＜0.01. The ALT, AST and TBIL were higher than that in B group aswell, P＜0.01. No significance is exist about TBIL between A group and B group,(P＞0.05). Liver MDA concentration in C group was significantly lower than that ingroup A and groupB, but the level of liver SOD activity was reversely(P＜0.01).Liver SOD activity, 51.03±5.22 (U/mgprot),in group B was higher than that ingroup A, 36.05±4.35(U/mgprot),P＜0.01. Liver MDA concentration in group A washigher than that in group B as well. The expression of liver IL-1 mRNA andTNF-a mRNA in group A was significantly higher than B,(P＜0.01).Plasmaendotoxin levels in A group,0.86±0.25 (EU/L), was significantly higher than Cgroup(P＜0.01) and B group,0.61±0.23(EU/L), (P＜0.05). No significance isexist compared endotoxin levels in B group with that in C group, (P＞0.05). 3. Transmission electron microscopy revealed that the ultra micro-construction ofthe liver graft in C group, but in A group the liver graft presented hepatic celledema, degeneration even necrosis, sinus stegnosis. The lesion of the hepaticcell and mesenchyme was milder in group B than that in group A. Opticsmicroscopy revealed that the micro-construction of ileal mucosa in shamegroup stayed normal. The epithelium of ileal mucosa in group A were lost anddisrupted. The lesion of the epithelial basement membrane in group B wasmilder than that in group A.【conclusion】This investigation implied that recipient hypoxic preconditioning may relieve ratintestinal mucosa injury induced by intestinal stagnant anoxia in anhepatic phase and liverearly-stage ischemia reperfusion injury during liver transplantation course. Hypoxicpreconditioning mitigated hypoxia/reoxygenation-induced intestinal injury and protectintestinal mucosa barrier function,which alleviated intestinal bacterium translocation and theendotoxin absorbed into systemic circulation so that it can improve the graft liver function andprolong the graft survival.Hypoxic preconditioning on recipient may provide a novel approachto protecting the reperfusion injury of liver transplanted and decreasing the rate of liver nofunction in postoperation.