Heme oxygenase-1 alleviates ischemia/reperfusion injury in aged liver.

To investigate if ischemia/reperfusion (I/R) injury in aged liver could be alleviated by heme oxygenase-1 (HO-1). Three groups of SD rats (16 mo old) were studied. Group 1: control donors received physiological saline 24 h before their livers were harvested; group 2: donors were pretreated with hemin 24 h before their livers were harvested; and group 3: donors received hemin 24 h before their livers were harvested and zinc protoporphyrin (ZnPP, HO-1 inhibitor) was given to recipients at reperfusion. The harvested livers were stored in University of Wisconsin solution (4 degrees) for 6 h, and then transplanted to syngeneic rats. Serum glutamic oxaloacetic transaminase (SGOT), apoptotic cells, and apoptotic gene were measured 3, 6, 12, 24, 48 h after reperfusion. We measured the apoptotic index by TUNEL, determined the expression of antiapoptotic Bcl-2 and proapoptotic (caspase-3) gene products by Western blot. After 3, 6, 12, 24, and 48 h of reperfusion, the SGOT levels (584.4+/-85.8 u/L, 999.2+/-125.2 u/L, 423.4+/-161.3 u/L, 257.8+/-95.8 u/L, and 122.4+/-26.4 u/L) in hemin group were significantly (all P<0.05) lower than those in saline group (1082.2+/-101.2 u/L, 1775.2+/-328.3 u/L, 840.4+/-137.8 u/L, 448.6+/-74.3 u/L, and 306.2+/-49.3 u/L). Liver HO-1 enzymatic activity correlated with beneficial effects of hemin and deleterious effects of adjunctive ZnPP treatment. Markedly less apoptotic (TUNEL+) liver cells 3, 6, 12, 24, and 48 h after reperfusion (5.16+/-0.73, 10.2+/-0.67, 9.28+/-0.78, 7.14+/-1.12, and 4.78+/-0.65) (P<0.05) could be detected in hemin liver grafts, as compared to controls (7.82+/-1.05, 15.94+/-1.82, 11.67+/-1.59, 8.28+/-1.09, and 6.36+/-0.67). We detected the increased levels of Bcl-2 (1.5-fold) expression and compared with saline controls. These differences were most pronounced at 12 h after transplantation. In contrast, an active form of proapoptotic caspase-3 (p20) protein was found to be 2.9-fold lower at 24 h in hemin-pretreated group, as compared to saline liver transplant controls. HO-1 overexpression can provide potent protection against cold I/R injury. This effect depends, at least in part, on HO-1-mediated inhibition of antiapoptotic mechanism.

Wang XH ，Wang K ，Zhang F ，Li XC ，Li J ，De W ，Guo J ，Qian XF ，Fan Y ... -  《-》

Heme oxygenase-1 overexpression protects rat hearts from cold ischemia/reperfusion injury via an antiapoptotic pathway.

Ischemia/reperfusion (I/R) injury is one of the most important causes of the early graft loss. We have shown that overexpression of heme oxygenase-1 (HO-1), an inducible heat shock protein 32, protects rat livers against I/R injury. We report on the cytoprotective effects of HO-1 in a rat cardiac I/R injury model, using cobalt protoporphyrin (CoPP) as HO-1 inducer and zinc protoporphyrin (ZnPP) as HO-1 inhibitor. Three groups of Lewis rats were studied: group 1 control donors received phosphate-buffered saline 48 hr before the harvest; group 2 donors were pretreated with CoPP at -48 hr; and in group 3, donors received CoPP at -48 hr and ZnPP was given to recipients at reperfusion. Hearts were harvested, stored in University of Wisconsin solution (4 degrees C) for 24 hr, and then transplanted to syngeneic (Lewis) rats. Sixty percent of control grafts ceased their function in <15 min. In contrast, 80% of CoPP-pretreated grafts survived 14 days. All grafts stopped functioning within 24 hr after CoPP + ZnPP therapy. Cardiac HO-1 enzymatic activity and protein expression correlated with beneficial effects of CoPP and deleterious effects of adjunctive ZnPP treatment. Markedly less apoptotic (TUNEL+) myocyte/endothelial cells could be detected in CoPP cardiac grafts, as compared with controls. The expression of antiapoptotic (Bcl-2/Bag-1) proteins was up-regulated in the CoPP group. HO-1 overexpression provides potent protection against cold I/R injury in a stringent rat cardiac model. This effect depends, at least in part, on HO-1-mediated up-regulation of a host antiapoptotic mechanism, especially in the early postreperfusion period.

Katori M ，Buelow R ，Ke B ，Ma J ，Coito AJ ，Iyer S ，Southard D ，Busuttil RW ，Kupiec-Weglinski JW ... -  《TRANSPLANTATION》

Alleviating ischemia-reperfusion injury in aged rat liver by induction of heme oxygenase-1.

Heme oxygenase-1 (HO-1), a cytoprotective protein, may be important in ameliorating hepatic ischemia-reperfusion (I/R) injury, a critical factor in the dysfunction of the aged liver after transplantation. We used hemin to overexpress HO-1 and analyze its effects in a model of I/R in aged livers used for orthotopic transplantation. The SGOT levels in the hemin group were significantly lower than those of the saline treatment group. Hemin liver grafts showed markedly fewer apoptotic (TUNEL+) liver cells after reperfusion compared with the controls. The plasma nitric oxide levels in the hemin group were significantly lower than those in the control group. Unlike untreated or hemin + Znpp-treated orthotopic liver transplant controls, iNOS expression in the hemin group was almost absent at 12 and 24 hours, after reperfusion. In contrast, eNOS was comparable in hemin and saline orthotopic liver transplants. The increased levels of Bcl-2 expression compared with saline controls were most pronounced at 12 hours after transplantation. In contrast, caspase 3 was lower at 24 hours among the hemin-pretreated group compared with saline-treated liver transplant controls. HO-1 alleviated the I/R injury in the aged liver by suppressing local expression of inducible nitric oxide synthase and by modulating pro- and antiapoptotic pathways.

Wang XH ，Wang K ，Zhang F ，Li XC ，Qian XF ，Cheng F ，Li GQ ，Fan Y ... -  《TRANSPLANTATION PROCEEDINGS》

Extended preservation of rat liver graft by induction of heme oxygenase-1.

Livers can be preserved only for a short period without jeopardizing the transplantation outcome. Heat shock proteins (HSPs) protect against ischemia and reperfusion injury. We studied whether their induction and, in particular, the induction of heme oxygenase 1 (HO-1), improves transplantation survival after an extended time of cold storage. Rats were subjected to heat preconditioning (42 degrees C for 20 minutes). Livers were harvested 24 hours later, preserved in cold University of Wisconsin solution for 44 hours, and transplanted in isogeneic rats (arterialized transplantation). HO-1 was specifically induced and inhibited by cobalt protoporphyrin and tin protoporphyrin, respectively. All animals receiving a graft without preconditioning and subjected to 44 hours of cold preservation died within 3 days, whereas 89% of rats who received a graft exposed to heat survived for 3 weeks (P =.0004). Preconditioning reduced serum aspartate transaminase (AST) and lactate dehydrogenase activities after reperfusion, improved bile flow, and decreased the histologic lesions of reperfusion injury. These significant effects of heat preconditioning were prevented by administration of tin protoporphyrin and could be reproduced by administration of cobalt protoporphyrin. In grafts without preconditioning, only a small fraction (<5%) of hepatocytes were positive with the terminal deoxynucleotide transferase-mediated dUTP nick-end labeling (TUNEL) assay, and even less expressed activated caspase 3. Preconditioning tended to reduce the number of positive cells and to stimulate the expression of antiapoptotic Bcl-X(L). In conclusion, heat preconditioning and, specifically, overexpression of HO-1 improve posttransplantation survival and graft function after prolonged cold ischemia preservation. The mechanism underlying these beneficial effects does not appear to be prevention of apoptosis.

Redaelli CA ，Tian YH ，Schaffner T ，Ledermann M ，Baer HU ，Dufour JF ... -  《HEPATOLOGY》

[Effect of heme oxygenase on apoptosis and apoptosis genes in hepatic ischemia reperfusion injury in rats].

To use heme oxygenase (HO) inducer hemin and a HO inhibitor zinc protoporphyrin (ZnPP) to investigate the effect of HO on apoptosis and apoptosis genes in hepatic ischemia reperfusion (IR) injury in rats. Ninety-six Sprague-Dawley rats were randomly divided into four groups (24 rats in each): a sham-operation group, an ischemia-reperfusion (IR) group, a hemin-IR group and a ZnPP-IR group. Liver functions, liver histology and hepatocellular apoptosis rates were observed at 0, 1.5, 4 and 8 hours after reperfusion. Hepatocellular apoptosis was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling; expressions of Bcl-2 and caspase-3 were determined by Western blot. Compared with the sham-operation group, the levels of ALT and AST were increased in the IR group. In the IR group the histological changes found in the livers were swelling of hepatocytes, narrowing of hepatic sinusoids, inflammatory cell infiltration and necrosis of hepatocytes in some areas of the livers. In the IR group rate of hepatocellular apoptosis was increased at 0, 1.5, 4 and 8 hours after reperfusion; expression of Bcl-2 was decreased and the expression of caspase-3 was increased. In the hemin-IR group, the levels of ALT and AST were lower, the pathological changes were milder and the rate of hepatocellular apoptosis was lower at 0, 1.5, 4 and 8 hours in comparison to those of the IR group. The expression of Bcl-2 was higher and the expression of caspase-3 was lower in the hemin-IR group in comparison to those of the IR group. The results in the ZnPP-IR group were just the opposite to those of the hemin-IR group. HO might play a protective role in hepatic IR injury in rats, and this effect may be related to the inhibition of hepatocellular apoptosis.

Wang YY ，Feng ZJ ，Yue YY ，Song M ，Song WJ ... -  《-》