• Archives of Pharmacal Research
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• v.28 no.12
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• pp.1392-1399
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• 2005

This study evaluated the effect of $\alpha$-tocopherol ($\alpha$-TC), ischemic preconditioning (IPC) or a combination on the extent of mitochondrial injury caused by hepatic ischemia/reperfusion (I/R). Rats were pretreated with $\alpha$-TC (20 mg/kg per day, i.p.) for 3 days before sustained ischemia. A rat liver was preconditioned with 10 min of ischemia and 10 min of reperfusion, and was then subjected to 90 min of ischemia followed by 5 h or 24 h of reperfusion. I/R increased the aminotransferase activity and mitochondrial lipid peroxidation, whereas it decreased the mitochondrial glutamate dehydrogenase activity. $\alpha$-TC and IPC individually attenuated these changes. $\alpha$-TC combined with IPC ($\alpha$-TC+IPC) did not further attenuate the changes. The mitochondrial glutathione content decreased after 5 h reperfusion. This decrease was attenuated by $\alpha$-TC, IPC, and $\alpha$-TC+IPC. The significant production of peroxides observed after 10 min reperfusion subsequent to sustained ischemia was attenuated by $\alpha$-TC, IPC, and $\alpha$-TC+IPC. The mitochondria isolated after I/R were rapidly swollen. However, this swelling rate was reduced by $\alpha$­TC, IPC, and $\alpha$-TC+IPC. These results suggest that either $\alpha$-TC or IPC reduces the level of mitochondrial damage associated with oxidative stress caused by hepatic I/R, but $\alpha$- TC combined with IPC offers no significant additional protection.

• Journal of Ginseng Research
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• v.33 no.4
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• pp.283-293
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• 2009

Ginsenosides, one of the most well-known traditional herbal medicines, are used frequently in Korea for the treatment of cardiovascular symptoms. The effects of ginseng saponin on ischemia-induced isolated rat heart were investigated through analyses of hemodynamic changes including perfusion pressure, aortic flow, coronary flow, and cardiac output. Isolated rat hearts were perfused and then subjected to 30 min of global ischemia followed by 60 min of reperfusion with modified Kreb's Henseleit solution. Myocardial contractile function was continuously recorded. Ginseng saponin administered before inducing ischemia significantly prevented decreases in perfusion pressure, aortic flow, coronary flow, and cardiac output. The ginseng saponin administered group significantly recovered all of the hemodynamic parameters, except heart rate, after ischemia-reperfusion (I/R) compared with ischemia control. The intracellular calcium ($[Ca^{2+}]_i$) content in rat neonatal cardiomyocytes was quantitatively determined. Administration of ginseng saponin significantly prevented $[Ca^{2+}]_i$ increase that had been induced by simulated I/R in vitro (p<0.01) in a dose-dependent manner, suggesting that the cardioprotection of ginseng saponin is mediated by the inhibition of $[Ca^{2+}]_i$ increase. Overall, we found that the administration of ginseng saponin has cardioprotective effects on the isolated rat heart after I/R injury. These results indicate that ginseng saponin has distinct cardioprotective effects in an I/R-induced rat heart.

• Archives of Pharmacal Research
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• v.27 no.1
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• pp.111-117
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• 2004

Hepatic microcirculatory failure is a major component of reperfusion injury in the liver. Recent data provided some evidence that endothelium-derived vasoconstrictors and vasodilators may be functionally important to the control of the total hepatic blood flow under these conditions of circulatory failure. Since Kupffer cells provide signals that regulate the hepatic response in ischemia/reperfusion (I/R), the aim of this study was to investigate the role of Kupffer cells in the I/R-induced imbalance of vasoregulatory gene expression. Rats were subjected to 60 min hepatic ischemia, followed by 5 h of reperfusion. The Kupffer cells were inactivated by gadolinium chloride ($GdCl_3$, 7.5 mg/kg body weight, intravenously) 1 day prior to ischemia. Liver samples were obtained 5 hrs after reperfusion for RT-PCR analysis of the mRNA for genes of interest: endothelin-1 (ET-1), its receptors $ET_A and ET_B$, endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS) and heme oxygenase-1 (HO-1). ET-1 mRNA expression was increased by I/R. mRNA levels for $ET_A$ receptors showed no change, whereas $ET_B$ receptor transcripts increased in the I/R group. The increases in ET-1 and $ET_B$ mRNA were not prevented by the $GdCI_3$ pretreatment. The mRNA levels for iNOS and eNOS significantly increased within the I/R group with no significant difference between the I/R group and the $GdCl_3$-treated I/R group. HO-1 mRNA expression significantly increased in the I/R group and this increase was attenuated by $GdCI_3$. In conclusion, we have demonstrated that an imbalance in hepatic vasoregulatory gene expression occurs during I/R. Our findings suggest that the activation of Kupffer cells is not required for I/R-induced hepatic microvascular dysfunction.

• Archives of Pharmacal Research
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• v.25 no.6
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• pp.940-945
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• 2002

The present study was done to determine the effect of trolox C, a hydrophilic analogue of vitamin E, on hepatic injury, especially the alteration in cytochrome P-450 (CYP)-dependent drug metabolism during ischemia and reperfusion (I/R). Rats were subjected to 60 min of hepatic ischemia and 5 h of reperfusion. Rats were treated intravenously with trolox C (2.5 mg/kg) or vehicle (PBS, pH 7.4), 5 min before reperfusion. Serum alanine aminotransferase and lipid peroxidation levels were markedly increased after I/R. This increase was significantly suppressed by trolox C. Cytochrome P-450 content was decreased after I/R but was restored by trolox C. There were no significant differences in ethoxyresorufin O-dealkylase (CYP 1A1) and methoxyresorufin O-dealkylase (CYP 1A2) activities among any of the experimental groups. Pentoxyresorufin O-dealkylase (CYP 2B1) activity was decreased and aniline p-hydroxylase (CYP 2E1) activity was increased after I/R. Both these changes were prevented by trolox C. Our findings suggest that trolox C reduces hepatocellular damage as indicated by abnormalities in microsomal drug-metabolizing function during I/R, and that this protection is, in part, caused by decreased lipid peroxidation.

• YAKHAK HOEJI
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• v.56 no.4
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• pp.260-267
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• 2012

This study examined the effects of baicalin, a bioactive flavonoid isolated from Scutellaria baicalensis, on hepatic injury caused by ischemia/reperfusion (I/R) in alcoholic fatty liver. Rats were fed an ethanol liquid diet or a control isocaloric diet for 5 weeks, and then subjected to 60 min of hepatic ischemia and 5 h of reperfusion. Baicalin (200 mg/kg) was administered intraperitoneally 24 and 1 h before ischemia. After reperfusion, baicalin attenuated the increase in serum alanine aminotransferase activity. The levels of cytosolic cytochrome c protein expression, caspase-3 activity, the number of apoptotic cells increased after reperfusion, which were higher in ethanol-fed animals, were attenuated by baicalin. Following I/R, the hepatic lipid peroxidation was elevated, whereas hepatic glutathione content was decreased. These changes attenuated by baicalin. In ethanol-fed animals, baicalin augmented the increases in heme oxygenase-1 protein and mRNA expressions, and nuclear Nrf2 expression. In conclusion, our findings suggest that baicalin ameliorates I/R-induced hepatocellular damage by suppressing apoptosis and oxidative stress in alcoholic fatty liver.

• Archives of Pharmacal Research
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• v.27 no.7
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• pp.769-775
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• 2004

Hepatic ischemia and reperfusion (l/R) predisposes the liver to secondary stresses such as endotoxemia, possibly via dysregulation of the hepatic microcirculation secondary to an imbalanced regulation of the vascular stress genes. In this study, the effect of hepatic I/R on the hepatic vasoregulatory gene expression in response to endotoxin was determined. Rats were subjected to 90 min of hepatic ischemia and 6 h of reperfusion. Lipopolysaccharide (LPS, 1 mg/kg) was injected intraperitoneally after reperfusion. Plasma and liver samples were obtained 6 h after reperfusion for serum aminotransferase assays and RT-PCR analysis of the mRNA for the genes of interest： endothelin-1 (ET-1), its receptors $ET_A$ and $ET_B$, endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), heme oxygenase-1 (HO-1), cyciooxygenase-2 (COX-2), and tumor necrosis factor-a (TNF-${\alpha}$). The activities of serum aminotransferases were significantly increased in the I/R group. This increase was markedly potentiated by LPS treatment. The ET-1 mRNA was increased by LPS alone, and this increase was significantly greater in both the I/R alone and I/R ＋ LPS groups compared to the sham. There were no significant differences in ETA receptor mRNA levels among any of the experimental groups. $ET_B$ mRNA was increased by both LPS alone and I/R alone, with no significant difference between the I/R alone and I/R ＋ LPS groups. The eN OS and HO-1 transcripts were increased by I/R alone and further increased by I/R ＋ LPS. The iNOS mRNA levels were increased by I/R alone, but increased significantly more by both LPS alone and I/R ＋ LPS compared to I/R alone. The TNF-${\alpha}$ mRNA levels showed no change with I/R alone, but were increased by both LPS alone and I/R ＋ LPS. The COX-2 expression was increased significantly by I/R alone and significantly more by I/R ＋ LPS. Taken collectively, significantly greater induction of the vasodilator genes over the constriction forces was observed with I/R ＋ LPS. These results may partly explain the increased susceptibility of ischemic livers to injury as a result of endotoxemia.

• Advances in Traditional Medicine
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• v.9 no.1
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• pp.67-73
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• 2009

Temporary clamping of the portal triad is a common strategy to minimize bleeding during liver transplantation. Increasing evidences suggests that oxygen derived free radicals and reintroduction of oxygen in ischemic tissue lead to ischemic and reperfusion injury (I/R) and lead to apoptosis and necrosis. Adult Wistar rat subjected to 60 min of partial liver ischemia followed by three hour reperfusion. Eighteen Wister rats were divided into sham-operated control group (I) (n = 6), ischemia and reperfusion group (II) (n = 6), folic acid treated group (1 mg/kg body weight/daily by oral route for 7 days before induced ischemia reperfusion maneuver) (III) (n = 6). Apoptotic and necrotic hepatocytes, mitochondrial antioxidant enzymes were measured. Liver injury was assessed by alanine transaminases (ALT), aspartate transaminases (AST), liver histopathology and electron microscopy. An ischemic and reperfusion hepatocellular injury was indicated by increased serum-ALT, AST, histopathology and electron microscopy studies. Apoptotic and necrotic cells were increased which was revealed by flow cytometry in I/R group. Pre- treatment with folic acid significantly decreased serum -ALT, AST levels, apoptotic and necrotic cells after 1 h ischemia followed by 3 h of reperfusion. Histopathology and TEM studies showed markedly diminished hepatocellular injury in folic acid pretreated rats during the hepatic I/R, which reached a level comparable to saline-treated rat of sham operated group. On the basis of our findings it may be concluded that folic acid afforded significant protection from necrosis and apoptosis in I/R injury.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.125.2-125.2
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• 2003

Hepatic ischemia and reperfusion predisposes the liver to secondary stresses such as endotoxemia possibly via dysregulation of the hepatic microcirculation secondary to imbalanced regulation of vascular stress gene. In this study, we determined the effect of endotoxin on hepatic vasoregulatory gene expression in response to hepatic ischemia and reperfusion (I/R). Rats were subjected to 90 min of hepatic ischemia and 6 h of reperfusion. Lipopolysaccharide (LPS, 1 mg/kg) was injected intraperitoneally after reperfusion. (omitted)

• Biomolecules & Therapeutics
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• v.21 no.2
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• pp.132-137
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• 2013

Geniposide is an active product extracted from the gardenia fruit, and is one of the most widely used herbal preparations for liver disorders. This study examined the cytoprotective properties of geniposide and its metabolite, genipin, against hepatic ischemia/reperfusion (I/R) injury. C57BL/6 mice were subjected to 60 min of ischemia followed by 6 h of reperfusion. Geniposide (100 mg/kg) and genipin (50 mg/kg) were administered orally 30 min before ischemia. In the I/R mice, the levels of serum alanine aminotransferase and hepatic lipid peroxidation were elevated, whereas hepatic glutathione/glutathione disulfide ratio was decreased. These changes were attenuated by geniposide and genipin administration. On the other hand, increased hepatic heme oxygenase-1 protein expression was potentiated by geniposide and genipin administration. The increased levels of tBid, cytochrome c protein expression and caspase-3 activity were attenuated by geniposide and genipin. Increased apoptotic cells in the I/R mice were also significantly reduced by geniposide and genipin treatment. Our results suggest that geniposide and genipin offer significant hepatoprotection against I/R injury by reducing oxidative stress and apoptosis.

• Archives of Pharmacal Research
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• v.27 no.2
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• pp.225-231
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• 2004

This study was designed to investigate the effect of Trolox, a hydrophilic analogue of vitamin E, on the alteration of vasoregulatory gene expression during hepatic ischemia and reperfusion (I/R). Rats were subjected to 60 min of hepatic ischemia in vivo. The rats were treated intravenously with Trolox (2.5 mg/kg) or the vehicle as a control 5 min before reperfusion. Liver samples were obtained 5 h after reperfusion for a RT-PCR analysis on the mRNA for the genes of interest. These mRNA peptides are endothelin-1 (ET -1), potent vasoconstrictor peptide, its receptor $ET_A$ and $ET_B$, vasodilator endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), heme oxygenase-1 (HO-1), tumor necrosis factor-$\alpha$ (TNF-$\alpha$) and cyclooxygenase-2 (COX-2). It was seen that serum alanine aminotransferase and lipid peroxi-dation levels were markedly increased after I/R and Trolox significantly suppressed this increase. In contrast, the glutathione concentration decreased in the I/R group, and this decrease was inhibited by Trolox. ET-1 mRNA expression was increased by I/R, an increase which was prevented by Trolox. The mRNA levels for $ET_A$ receptor was significantly decreased, whereas ET$_{B}$ receptor transcript increased in the I/R group. The increase in $ET_A$ was prevented by Trolox. The mRNA levels for iNOS and HO-1 significantly increased in the I/R group and Trolox attenuated this increase. There were no significant differences in eNOS mRNA expression among any of the experimental groups. The mRNA levels for COX-2 and TNF-$\alpha$ significantly increased in I/R group and Trolox also attenuated this increase. Our findings suggest that I/R induces an imbalanced hepatic vasoregulatory gene expression and Trolox ameliorates this change through its free radical scavenging activity.y.