Hisashi Ozasa

Prior induction of heme oxygenase-1 with glutathione depletor ameliorates the renal ischemia and reperfusion injury in the rat.

Heme oxygenase (HO)‐1 catalyzes the rate‐limiting step in heme degradation releasing iron, carbon monoxide, and biliverdin. Induction of HO‐1 occurs as an adaptive and protective response to oxidative stress. Ischemia and reperfusion (IR) injury seems to be mainly caused by the oxidative stress. In this study, we have examined whether prior induction of HO‐1 with buthionine sulfoximine (BSO), a glutathione (GSH) depletor, affects the subsequent renal IR injury. BSO (2 mmol/kg body weight) was administered intraperitoneally into rats, the levels of HO‐1 protein increased within 4 h after the injection. When BSO was administered into rats at 5 h prior to the renal 45 min of ischemia, the renal IR injury was assessed by determining the levels of blood urea nitrogen and serum creatinine, markers for renal injury, after 24 h of reperfusion. The renal injury was significantly improved as compared to the rats treated with IR alone. Administration of zinc‐protoporphyrin IX, an inhibitor of HO activity, reduced the efficacy of BSO pretreatment on the renal IR injury. Our findings suggest that the prior induction of HO‐1 ameliorates the subsequent renal IR injury.

Hemin pretreatment ameliorates aspects of the nephropathy induced by mercuric chloride in the rat

Mercuric chloride (HgCl(2)) is known to be a nephrotoxicant. When HgCl(2) is administered into rats, acute renal failure (ARF) is induced. Heme oxygenase-1 (HO-1) is antioxidative enzyme and is known to play a protective role against the oxidative injury. To elucidate the cytoprotective role of HO-1 against the nephrotoxicant-induced ARF, we examined the effect of hemin, HO-1 inducer, on HgCl(2)-induced ARF. Subcutaneous administration of hemin (30 mg/kg body weight) into rats once a day for two successive days obviously induced HO-1 protein in the kidneys at 24 h after the last injection. Under this situation, when HgCl(2) (1 mg/kg body weight) was intraperitoneally injected into rats at 24 h after the last injection of hemin improved the serum creatinine (SCr) and blood urea nitrogen (BUN) levels, markers for renal injury, at 24 h after the HgCl(2) injection as compared with the control rats without hemin pretreatment (HgCl(2) treatment alone). This result was further confirmed by histopathological analysis. These findings strongly suggest that the preinduction of HO-1 ameliorates the subsequent HgCl(2)-induced acute renal injury.

Induction of heme oxygenase-1 in toxic renal injury: mercuric chloride-induced acute renal failure in rat

It is known that mercuric chloride (HgCl2) is a nephrotoxicant. When HgCl2 (1 mg/kg body weight) was intraperitoneally injected into rats, acute renal failure was induced. Histological changes in the kidneys were exclusively observed in the proximal tubules and the severe necrosis was found as early as 24 h after HgCl2 injection. The heme oxygenase-1 (HO-1) mRNA was strongly and promptly induced at about 2.5 h, the earliest time examined and abruptly decreased after the injection. Whereas the time course of HO-1 protein level was delayed as compared with that of HO-1 mRNA level. The levels of HO-1 mRNA and protein similarly increased with dose-dependent manner. The localization of HO-1 protein was restricted to the tubule cells. These findings suggest the potential involvement of HO-1 induction in the response to HgCl2-induced acute renal injury.

Splenic artery ligation ameliorates hepatic ischemia and reperfusion injury in rats

Abstract: Background/Aims: Hepatic injury caused by ischemia/reperfusion (I/R) is a key clinical problem associated with liver transplantation and liver surgery. The spleen is involved in hepatic I/R injury. In this study, we examined the effects of splenic artery ligation on hepatic I/R injury.

Effects of Vitamin E Deficiency and Glutathione Depletion on Stress Protein Heme Oxygenase 1 mRNA Expression in Rat Liver and Kidney

Heme oxygenase 1 (HO-1) is a stress protein and has been suggested to provide defense mechanisms against agents that may induce oxidative injury. Vitamin E (VE) is considered to function as an important cellular antioxidant. Rats were fed a VE-deficient (0E) or a VE-sufficient (10E) diet for 6 weeks and then were intraperitoneally administered buthionine sulfoximine (BSO), a glutathione (GSH)-depleting reagent. Whereas HO-1 mRNA levels were undetectable in untreated 0E and 10E rat livers, BSO administration induced HO-1 mRNA expression in both 0E and 10E rat livers. High levels of HO-1 mRNA expression were observed in particular in BSO-treated 0E rat livers. The time-course of changes in HO-1 mRNA expression in 0E rat liver after BSO administration showed that HO-1 mRNA expression was transiently induced at 2.5 hr after BSO treatment, the earliest time examined. In addition, to determine whether VE deficiency and GSH depletion affect the expression of HO-1 mRNA in other tissues, we also examined the time-course of HO-1 mRNA expression in BSO-treated 0E rat kidney. The expression pattern of HO-1 mRNA in the kidney was very similar to that in the liver, and the peak was also observed at about 2.5 hr after BSO administration. Interestingly, histologic assessment of liver and kidney showed that VE deficiency and GSH depletion induced injury in the kidney, but not in the liver.

Changes in serum lactate dehydrogenase isozyme-X activity observed after cadmium administration

After subcutaneous (s.c.) administration of cadmium (Cd), activity of lactate dehydrogenase isozyme-X (LDH-X) appeared in the serum of treated mice within 24 h. The determination of the activity of this enzyme in serum serves as a reliable and convenient method for early detection of testicular damage induced by Cd.

Splenic artery ligation: A protection against hepatic ischemia/reperfusion injury in partially hepatectomized rats.

Aim:  In liver resection, the temporary occlusion of the hepatoduodenal ligament (Pringle maneuver) is often used. However, the maneuver causes ischemia/reperfusion (I/R) injury in the remnant liver. Heme oxygenase (HO)‐1 has a cytoprotective role against this injury. Our aim is to investigate whether splenic artery ligation induces HO‐1 expression in the liver and ameliorates the hepatic I/R injury in partially hepatectomized rats.

Cytosolic Purine 5′-Nucleotidase from Chicken Heart : An Isozyme of the Liver Enzyme as Evidenced by Antibodies

Purine 5′-nucleotidase (1) is one of soluble nucleotidases which include pyrimidine 5′-nucleotidase (2), deoxyribonucleotidase (3), and AMP-specific 5′-nucleotidase (4). Purine 5′-nucleotidase preferentially hydrolyzes IMP, GMP, and, to a lesser extent, AMP in the presence of magnesium ions. The enzyme is allosterically activated by ATP (5), diadenosine tetraphosphate (6), 2,3-diphosphoglycerate (7) and decavanadate (8), and inhibited by Pi. Purine 5′-nucleotidase is located in the cytoplasmic matrix of the cell (9, 10).

103 PURINE 5′-NUCLEOTIDASE—ITS REESTIMATED SUBUNIT MOLECULAR MASS AND IMMUNOCYTOCHEMICAL LOCALIZATION IN CHICKEN LIVER

Purine 5′-nucleotidase, formerly termed cytosol 5′-nucleotidase (Tsushima, K. (1986) Adv Enzyme Regul 25, 181), is one of soluble nucleotidases including pyrimidine 5′-nucleotidase and deoxyribo-nucleotidase, and deferentially hydrolyzes IMP, GMP, and AMP in the presence of Mg++. The enzyme has been investigated to have allosteric properties characterized by activation by ATP, ADP, 2, 3-diphosphoglycerate, and diadenosine tetraphosphate. Purine 5′-nucleotidase, has been purified from various sources, but structural studies seem to be incomplete. The subunit molecular mass of chicken liver enzyme, which was earlier reported to be 51 kDa upon SDS-PAGE, was reinvestigated. By immunoblot analyses after SDS-PAGE, a crude fraction from the liver homogenized in the presence of leupeptin showed multiple bands around 57 kDa, and SDS-extracted proteins directly from the liver exhibited a single immunoreactive 70-kDa band. In vitro translation products using chicken liver polysomes also showed a radioactive 70-kDa band after immunoprecipitation. Immunocytocheraical study showed that the antigen was exclusively located in the cytoplasmic matrix of chicken liver sinusoidal and parenchymal cells, suggesting that physiological processing might not be the case with chicken liver enzyme. These results indicate that the subunit molecular mass of chicken liver purine 5′-nucleotidase might be 70 kDa, and the enzyme is the first case to be morphologically located in the cytosol among several known cytosolic nucleotidases.

Regulation of the Cytosol 5′-Nucleotidase of the Heart by Adenylate Energy Charge

Adenosine formed by the heart has been proposed to participate in the metabolic regulation of coronary blood flow [1]. Adenosine can be formed from AMP by action of 5′-nucleotidase or alkaline or acid phosphatase, or from S-adenosylhomocysteine by means of S-adenosyl-homocysteine hydrolase. A 5′-Nucleotidase in the heart was shown by histochemical studies to be associated with myocardial cell membrane [2], and functional studies indicate the enzyme to be an ectoenzyme [3].