AIM: To investigate the effects of resveratrol on liver ischemia/reperfusion (I/R) injury in rats. METHODS: A total of 40 male Sprague-Dawley rats weighing 240-290 g were randomized into four groups of ten: (1)...AIM: To investigate the effects of resveratrol on liver ischemia/reperfusion (I/R) injury in rats. METHODS: A total of 40 male Sprague-Dawley rats weighing 240-290 g were randomized into four groups of ten: (1) controls: data from unmanipulated animals; (2) sham group: rats subjected to the surgical procedure, except for liver I/R, and given saline; (3) I/R group: rats underwent liver ischemia for 45 rain followed by reperfusion for 45 rain; (4) I-R/Resveratrol group: rats pretreated with resveratrol (10 umol/L, iv). Liver tissues were obtained to determine antioxidant enzyme levels and for biochemical and histological evaluation. RESULTS: Plasma aminotransferase activities were higher in the I/R group than in the I-R/Resveratrol group. Malondialdehyde levels and the hepatic injury score decreased, while superoxide dismutase, catalase, and glutathione peroxidase levels increased in group 4 compared to group 3. In group 4, histopathological changes were significantly attenuated in resveratroltreated livers. CONCLUSION: These results suggest that resveratrol has protective effects against hepatic I/R injury, and is a potential therapeutic drug for ischemia reperfusionrelated liver injury.展开更多
AIM: To investigate the protective effect of isoflurane on energy balance in isolated hepatocytes during in vitro anoxia/reoxygenation, and to compare isoflurane with halothane. METHODS: Hepatocytes freshly isolated f...AIM: To investigate the protective effect of isoflurane on energy balance in isolated hepatocytes during in vitro anoxia/reoxygenation, and to compare isoflurane with halothane. METHODS: Hepatocytes freshly isolated from fed rats were suspended in Krebs-Henseleit buffer, and incubated in sealed flasks under O2/CO2 or N2/CO2 (95%/5%, V/V) for 30 or 60 min, followed by 5 or 10 min of reoxygenation, with an added volatile anesthetic or not. ATP, ADP, and adenosine monophosphate in hepatocytes were determined by high performance liquid chromatography, and energy charge was calculated. RESULTS: During 30 min of anoxia, the energy charge and total adenine nudeotide steadily increased with the isoflurane dose from 0 to 2 minimum alveolar anesthetic concentration (MAC), then decreased from 2 to 3 MAC. In short incubations (30-35 min) at 1 MAC isoflurane, energy charge modestly decreased during anoxia, which was partially prevented by isoflurane and completely reversed by reoxygenation, and total adenine nudeotide did not decrease. In long incubations (60-70 min), both energy charge and total adenine nudeotide greatly decreased during anoxia, with partial and no reversal by reoxygenation, respectively. Isoflurane partly prevented decreases in both energy charge and total adenine nudeotide during anoxia and reoxygenation. In addition, 1 MAC isoflurane obviously increased ATP/ADP, which could not be changed by 1 MAC halothane. CONCLUSION: Isoflurane partially protects isolated hepatocytes against decreases in both energy charge and total adenine nudeotide during short (reversible) or long (irreversible) anoxia.展开更多
AIM: To elucidate the mechanism of liver protection by inhibition of Kupffer cells (KCs) function.METHODS: All the animals were randomly divided into three groups. Blockade group (gadolinium chloride solution (G...AIM: To elucidate the mechanism of liver protection by inhibition of Kupffer cells (KCs) function.METHODS: All the animals were randomly divided into three groups. Blockade group (gadolinium chloride solution (GdCl3) injection plus ischemia/reperfusion (I/R) injury):GdCl3 solution was injected once every 24 h for 2 d via the tail vein before I/R injury. Non-blockade group (saline solution injection plus I/R injury): saline instead of GdCl3 as a control was injected as in the blockade group. Sham group: saline was injected without I/R injury. Liver samples were collected 4 h after blood inflow restoration. The blockade of the function of KCs was verified by immunostaining with an anti-CD68 mAb. Toll-like receptor2 (TLR2) was immunostained with a goat antimouse polydonal anti-TLR2 antibody. Membrane proteins were extracted from the liver samples and TLR2 protein was analyzed by Western blot. Portal vein serum and plasma were taken respectively at the same time point for further detection of the levels of tumor necrosis factor-α (TNF-α) and alanine aminotransferase (ALT), an indicator of liver function.I/R injury via downregulation of theexpression of TLR2.RESULTS: Compared to non-blockade group, CD^68+ cells significantly reduced in blockade group (OPTDI, optical density integral): 32.97±10.55 vs 185.65±21.88, P〈0.01) and the liver function impairment was relieved partially (level of ALT: 435.89±178.37 U/L vs 890.21±272.91 U/L,P〈0.01). The expression of TLR2 protein in blockade group significantly decreased compared to that in non- group(method of immunohistochemistry, OPDTI: 75.74±17.44 vs 170.58±25.14, P〈0.01; method of Western blot, A value: 125.89±15.49 vs 433.91±35.53, P〈0.02). The latter correlated with the variation of CD68 staining (r = 0.745,P〈0.05). Also the level of portal vein TNF-α decreased in blockade group compared to that in non-blockade group (84.45±14.73 ng/L vs 112.32±17.56 ng/L, P〈0.05), butwas still higher than that in sham group (84.45±14.73 ng/L vs 6.07±5.33 ng/L, P〈0.01).CONCLUSION: Inhibition of the function of KCs may protect liver against I/R injury via downregulation of the expression of TLR2.展开更多
AIM:To investigate the changing patterns of glycogen and enzyme histochemical activities in rat liver graft under a different warm ischemia time (WIT) and to predict the tolerant time limitation of the liver graft to ...AIM:To investigate the changing patterns of glycogen and enzyme histochemical activities in rat liver graft under a different warm ischemia time (WIT) and to predict the tolerant time limitation of the liver graft to warm ischemia injury. METHODS: The rats were randomized into five groups, WIT was 0,15,30,45,60 min, respectively, and histochemical staining of liver graft specimens was observed. The recovery changes of glycogen and enzyme histochemistry activities were measured respectively 6 and 24 h following liver graft implantation. RESULTS: The activities of succinic dehydrogenase, cytochrome oxidase, apyrase (Mg++-ATPase) and content of glycogen were decreased gradually after different WIT in a time-dependent manner. The changes were significant when WIT was over 30 min. CONCLUSION: Hepatic injury is reversible within 30 min of warm ischemia injury. Glycogen and enzyme histochemistry activities of liver grafts and their recovery potency after reperfusion may serve as criteria to evaluate the quality of liver grafts.展开更多
AIM: This study was designed to examine the hypothesis that gender differences in I/R injury are associated withendothelial cell nitric oxide synthase (eNOS)-derived nitric oxide (NO).METHODS: Wistar rats were randomi...AIM: This study was designed to examine the hypothesis that gender differences in I/R injury are associated withendothelial cell nitric oxide synthase (eNOS)-derived nitric oxide (NO).METHODS: Wistar rats were randomized into seven experimental groups (12 animals per group). Except for the sham operated groups, all rats were subjected to total liver ischemia for 40 min followed by reperfusion. All experimental groups received different treatments 45 min before the laparotomy. For each group, half of the animals (six) were used to investigate the survival; blood samples and liver tissues were obtained in the remaining six animals after 3 h of reperfusion to assess serum NO, alanine aminotransferase (ALT) and TNF-α levels, liver tissuemalondialdehyde (MDA) content, and severity of hepatic I/R injury.RESULTS: Basal serum NO levels in female sham operated (FS) group were nearly 1.5-fold of male sham operated (MS) group (66.7±11.0 μmol/L vs 45.3±10.1μmol/L, P<0.01). Although serum NO levels decreased significantly after hepatic I/R (P<0.01, vs sham operated groups), they were still significantly higher in female rat (F) group than in male rat (M) group (47.8±8.6 μmol/L vs 23.8±4.7 μmol/L, P<0.01). Serum ALT and TNF-α levels, and liver tissue MDA content were significantly lower in F group than in M group (370.5±46.4 U/L, 0.99±0.11 μg/L and 0.57±0.10 μmol/g vs668.7±78.7 U/L, 1.71±0.18 μg/Land 0.86±0.11 μmol/g, respectively, P<0.01). I/R induced significant injury to the liver both in M and F groups (P<0.01 vs sham operated groups). But the degree of hepatocyte injury was significantly milder in F group than in M group (P<0.05 and P<0.01). The median survival time was six days in F group and one day in M group. The overall survival rate was significantly higher in F group than in M group (P<0.05). When compared with male rats pretreated with saline (M group), pretreatment of male rats with 17-β- estradiol (E2) (M+E2 group) significantly increased serum NO levels and significantly decreased serum ALT and TNF-α levels, and liver tissue MDA content after I/R (P<0.01).The degree of hepatocyte injury was significantly decreased and the overall survival rate was significantly improved in M+E2 group than in M group (P<0.01 and P<0.05). TheNOS inhibitor Nw-nitro-L-arginine methyl ester (L-NAME) treatment could completely abolish the protective effects of estrogen in both male and female rats. CONCLUSION: The protective effects afforded to female rats subjected to hepatic I/R are associated with eNOSderived NO.展开更多
AIM: To determine whether mild hypothermia could protect liver against ischemia and reperfusion injury in pigs. METHODS: Twenty-four healthy pigs were randomly divided into normothermia, mild hypothermia and normal co...AIM: To determine whether mild hypothermia could protect liver against ischemia and reperfusion injury in pigs. METHODS: Twenty-four healthy pigs were randomly divided into normothermia, mild hypothermia and normal control groups. The experimental procedure consisted of temporary interruption of blood flow to total hepatic lobe for different lengths of time and subsequent reperfusion. Hepatic tissue oxygen pressure (PtiO2) and aspartate aminotransferase (AST) values were evaluated, and ultrastructural analysis was carried out for all samples. RESULTS: Serum AST was significantly lower, and hepatic PtiO2 values were significantly higher in the mild hypothermia group than in the normothermia group during liver ischemia-reperfusion periods (P= 0.032, P= 0.028). Meanwhile, the histopathologic injury of liver induced by ischemia-reperfusion was significantly improved in the mild hypothermia group, compared with that in the normothermia group. CONCLUSION: Mild hypothermia can protect the liver from ischemia-reperfusion injury in pigs.展开更多
AIM: To observe the hepatic injury induced by carbon dioxide pneumoperitoneum in rats and to explore its potential mechanism.METHODS: Thirty healthy male SD rats were randomly divided into control group (n = 10), ...AIM: To observe the hepatic injury induced by carbon dioxide pneumoperitoneum in rats and to explore its potential mechanism.METHODS: Thirty healthy male SD rats were randomly divided into control group (n = 10), 0 h experimental group (n = 10) and 1 h experimental group (n = 10) after sham operation with carbon dioxide pneumoperitoneum. Histological changes in liver tissue were observed with hematoxylineosin staining. Liver function was assayed with an automatic biochemical analyzer. Concentration of malonyldialdehyde (MDA) and activity of superoxide dismutase (SOD) were assayed by colorimetry. Activity of adenine nucleotide translocator in liver tissue was detected with the atractyloside-inhibitor stop technique. Expression of hypoxia inducible factor-1 (HIF-1) mRNA in liver tissue was detected with in situ hybridization.RESULTS: Carbon dioxide 60 min could induce liver pneumoperitoneum for injury in rats. Alanine aminotransferase and aspartate aminotransferase were 95.7 ± 7.8 U/L and 86.8 ± 6.9 U/L in 0 h experimental group, and 101.4 ± 9.3 U/L and 106.6 ±8.7 U/L in 1 h experimental group. However, no significant difference was found in total billirubin, albumin, and pre-albumin in the three groups. In 0 h experimental group, the concentration of MDA was 9.83 ±2.53 μmol/g in liver homogenate and 7.64 ± 2.19 μmol/g in serum respectively, the activity of SOD was 67.58±9.75 nu/mg in liver and 64.47 ± 10.23 nu/mg in serum respectively. In 1 h experimental group, the concentration of MDA was 16.57±3.45 μmol/g in liver tissue and 12.49 ±4.21 μmol/g in serum respectively, the activity of SOD was 54.29 ±7.96 nu/mg in liver tissue and 56.31 ±9.85 nu/mg in serum respectively. The activity of ANT in liver tissue was 9.52 ± 1.56 in control group, 6.37± 1.33 in 0 h experimental group and 7.2 8±1.45 (10^-9 mol/min per gram protein) in 1 h experimental group, respectively. The expression of HIF-1 mRNA in liver tissue was not detected in control group, and its optical density difference value was 6.14±1.03 in 0 h experimental group and 9.51 ± 1.74 in 1 h experimental group, respectively. CONCLUSION: Carbon dioxide pneumoperitoneum during the sham operation can induce hepatic injury in rats. The probable mechanisms of liver injury include anoxia, ischemia reperfusion and oxidative stress. Liver injury should be avoided during clinical laparoscopic operation with carbon dioxide pneumoperitoneum.展开更多
AIM: To compare different preconditioning strategies to protect the liver from ischemia/reperfusion injury focusing on the expression of pro- and anti-apoptotic proteins. Interventions comprised different modes of is...AIM: To compare different preconditioning strategies to protect the liver from ischemia/reperfusion injury focusing on the expression of pro- and anti-apoptotic proteins. Interventions comprised different modes of ischemic preconditioning (IP) as well as pharmacologic pretreatment by α-lipoic acid (LA). METHODS: Several groups of rats were compared: sham operated animals, non-pretreated animals (nt), animals receiving IP (10 rain of ischemia by clamping of the portal triad and 10 min of reperfusion) prior to sustained ischemia, animals receiving selective ischemic preconditioning (IPsel, 10 min of ischemia by selective clamping of the ischemic lobe and 10 rain of reperfusion) prior to sustained ichemia, and animals receiving 500 1μmol α-LA injected i.v. 15 min prior to the induction of 90 min of selective ischemia. RESULTS: Cellular damage was decreased only in the LA group. TUNEL-positive hepatocytes as well as necrotic hepatocyte injury were also decreased only by LA(19 ± 2 vs 10 ± 1, P〈 0.05 and 29 ± 5 vs 12 ± 1, P 〈 0.05). Whereas caspase 3- activities in liver tissue were unchanged, caspase 9- activity in liver tissue was decreased only by LA pretreatment (3.1 ± 0.3 vs 1.8 ± 0.2, P 〈 0.05). Survival rate as the endpoint of liver function was increased after IP and LA pretreatment but not after IPsel. Levels of lipid peroxidation (LPO) in liver tissue were decreased in the IP as well as in the LA group compared to the nt group. Determination of pro- and anti-apoptotic proteins showed a shift towards anti-apoptotic proteins by LA. In contrast, both our IP strategies failed to influence apototic cell death. CONCLUSION: IP, consisting of 10 min of ischemia and 10 min of reperfusion, ischemia/reperfusion injury protects only partly against of the liver prior to 90 min of selective ischemia. IPsel did not influence ischemic tolerance of the liver. LA improved tolerance to ischemia, possibly by downregulation of pro-apoptotic Bax.展开更多
文摘AIM: To investigate the effects of resveratrol on liver ischemia/reperfusion (I/R) injury in rats. METHODS: A total of 40 male Sprague-Dawley rats weighing 240-290 g were randomized into four groups of ten: (1) controls: data from unmanipulated animals; (2) sham group: rats subjected to the surgical procedure, except for liver I/R, and given saline; (3) I/R group: rats underwent liver ischemia for 45 rain followed by reperfusion for 45 rain; (4) I-R/Resveratrol group: rats pretreated with resveratrol (10 umol/L, iv). Liver tissues were obtained to determine antioxidant enzyme levels and for biochemical and histological evaluation. RESULTS: Plasma aminotransferase activities were higher in the I/R group than in the I-R/Resveratrol group. Malondialdehyde levels and the hepatic injury score decreased, while superoxide dismutase, catalase, and glutathione peroxidase levels increased in group 4 compared to group 3. In group 4, histopathological changes were significantly attenuated in resveratroltreated livers. CONCLUSION: These results suggest that resveratrol has protective effects against hepatic I/R injury, and is a potential therapeutic drug for ischemia reperfusionrelated liver injury.
基金Supported by the National Natural Science Foundation of China, No. 39900140
文摘AIM: To investigate the protective effect of isoflurane on energy balance in isolated hepatocytes during in vitro anoxia/reoxygenation, and to compare isoflurane with halothane. METHODS: Hepatocytes freshly isolated from fed rats were suspended in Krebs-Henseleit buffer, and incubated in sealed flasks under O2/CO2 or N2/CO2 (95%/5%, V/V) for 30 or 60 min, followed by 5 or 10 min of reoxygenation, with an added volatile anesthetic or not. ATP, ADP, and adenosine monophosphate in hepatocytes were determined by high performance liquid chromatography, and energy charge was calculated. RESULTS: During 30 min of anoxia, the energy charge and total adenine nudeotide steadily increased with the isoflurane dose from 0 to 2 minimum alveolar anesthetic concentration (MAC), then decreased from 2 to 3 MAC. In short incubations (30-35 min) at 1 MAC isoflurane, energy charge modestly decreased during anoxia, which was partially prevented by isoflurane and completely reversed by reoxygenation, and total adenine nudeotide did not decrease. In long incubations (60-70 min), both energy charge and total adenine nudeotide greatly decreased during anoxia, with partial and no reversal by reoxygenation, respectively. Isoflurane partly prevented decreases in both energy charge and total adenine nudeotide during anoxia and reoxygenation. In addition, 1 MAC isoflurane obviously increased ATP/ADP, which could not be changed by 1 MAC halothane. CONCLUSION: Isoflurane partially protects isolated hepatocytes against decreases in both energy charge and total adenine nudeotide during short (reversible) or long (irreversible) anoxia.
基金Supported by the National Natural Science Foundation of China, No. 30200272
文摘AIM: To elucidate the mechanism of liver protection by inhibition of Kupffer cells (KCs) function.METHODS: All the animals were randomly divided into three groups. Blockade group (gadolinium chloride solution (GdCl3) injection plus ischemia/reperfusion (I/R) injury):GdCl3 solution was injected once every 24 h for 2 d via the tail vein before I/R injury. Non-blockade group (saline solution injection plus I/R injury): saline instead of GdCl3 as a control was injected as in the blockade group. Sham group: saline was injected without I/R injury. Liver samples were collected 4 h after blood inflow restoration. The blockade of the function of KCs was verified by immunostaining with an anti-CD68 mAb. Toll-like receptor2 (TLR2) was immunostained with a goat antimouse polydonal anti-TLR2 antibody. Membrane proteins were extracted from the liver samples and TLR2 protein was analyzed by Western blot. Portal vein serum and plasma were taken respectively at the same time point for further detection of the levels of tumor necrosis factor-α (TNF-α) and alanine aminotransferase (ALT), an indicator of liver function.I/R injury via downregulation of theexpression of TLR2.RESULTS: Compared to non-blockade group, CD^68+ cells significantly reduced in blockade group (OPTDI, optical density integral): 32.97±10.55 vs 185.65±21.88, P〈0.01) and the liver function impairment was relieved partially (level of ALT: 435.89±178.37 U/L vs 890.21±272.91 U/L,P〈0.01). The expression of TLR2 protein in blockade group significantly decreased compared to that in non- group(method of immunohistochemistry, OPDTI: 75.74±17.44 vs 170.58±25.14, P〈0.01; method of Western blot, A value: 125.89±15.49 vs 433.91±35.53, P〈0.02). The latter correlated with the variation of CD68 staining (r = 0.745,P〈0.05). Also the level of portal vein TNF-α decreased in blockade group compared to that in non-blockade group (84.45±14.73 ng/L vs 112.32±17.56 ng/L, P〈0.05), butwas still higher than that in sham group (84.45±14.73 ng/L vs 6.07±5.33 ng/L, P〈0.01).CONCLUSION: Inhibition of the function of KCs may protect liver against I/R injury via downregulation of the expression of TLR2.
基金Supported by the Key Clinical Project of Minister of Public Health,No. 97040230 Scientific and Technological Committee of Guangdong Province, No. 99M4902G
文摘AIM:To investigate the changing patterns of glycogen and enzyme histochemical activities in rat liver graft under a different warm ischemia time (WIT) and to predict the tolerant time limitation of the liver graft to warm ischemia injury. METHODS: The rats were randomized into five groups, WIT was 0,15,30,45,60 min, respectively, and histochemical staining of liver graft specimens was observed. The recovery changes of glycogen and enzyme histochemistry activities were measured respectively 6 and 24 h following liver graft implantation. RESULTS: The activities of succinic dehydrogenase, cytochrome oxidase, apyrase (Mg++-ATPase) and content of glycogen were decreased gradually after different WIT in a time-dependent manner. The changes were significant when WIT was over 30 min. CONCLUSION: Hepatic injury is reversible within 30 min of warm ischemia injury. Glycogen and enzyme histochemistry activities of liver grafts and their recovery potency after reperfusion may serve as criteria to evaluate the quality of liver grafts.
文摘AIM: This study was designed to examine the hypothesis that gender differences in I/R injury are associated withendothelial cell nitric oxide synthase (eNOS)-derived nitric oxide (NO).METHODS: Wistar rats were randomized into seven experimental groups (12 animals per group). Except for the sham operated groups, all rats were subjected to total liver ischemia for 40 min followed by reperfusion. All experimental groups received different treatments 45 min before the laparotomy. For each group, half of the animals (six) were used to investigate the survival; blood samples and liver tissues were obtained in the remaining six animals after 3 h of reperfusion to assess serum NO, alanine aminotransferase (ALT) and TNF-α levels, liver tissuemalondialdehyde (MDA) content, and severity of hepatic I/R injury.RESULTS: Basal serum NO levels in female sham operated (FS) group were nearly 1.5-fold of male sham operated (MS) group (66.7±11.0 μmol/L vs 45.3±10.1μmol/L, P<0.01). Although serum NO levels decreased significantly after hepatic I/R (P<0.01, vs sham operated groups), they were still significantly higher in female rat (F) group than in male rat (M) group (47.8±8.6 μmol/L vs 23.8±4.7 μmol/L, P<0.01). Serum ALT and TNF-α levels, and liver tissue MDA content were significantly lower in F group than in M group (370.5±46.4 U/L, 0.99±0.11 μg/L and 0.57±0.10 μmol/g vs668.7±78.7 U/L, 1.71±0.18 μg/Land 0.86±0.11 μmol/g, respectively, P<0.01). I/R induced significant injury to the liver both in M and F groups (P<0.01 vs sham operated groups). But the degree of hepatocyte injury was significantly milder in F group than in M group (P<0.05 and P<0.01). The median survival time was six days in F group and one day in M group. The overall survival rate was significantly higher in F group than in M group (P<0.05). When compared with male rats pretreated with saline (M group), pretreatment of male rats with 17-β- estradiol (E2) (M+E2 group) significantly increased serum NO levels and significantly decreased serum ALT and TNF-α levels, and liver tissue MDA content after I/R (P<0.01).The degree of hepatocyte injury was significantly decreased and the overall survival rate was significantly improved in M+E2 group than in M group (P<0.01 and P<0.05). TheNOS inhibitor Nw-nitro-L-arginine methyl ester (L-NAME) treatment could completely abolish the protective effects of estrogen in both male and female rats. CONCLUSION: The protective effects afforded to female rats subjected to hepatic I/R are associated with eNOSderived NO.
基金Supported by the Health Committee of Guangdong Province, No.A1998550
文摘AIM: To determine whether mild hypothermia could protect liver against ischemia and reperfusion injury in pigs. METHODS: Twenty-four healthy pigs were randomly divided into normothermia, mild hypothermia and normal control groups. The experimental procedure consisted of temporary interruption of blood flow to total hepatic lobe for different lengths of time and subsequent reperfusion. Hepatic tissue oxygen pressure (PtiO2) and aspartate aminotransferase (AST) values were evaluated, and ultrastructural analysis was carried out for all samples. RESULTS: Serum AST was significantly lower, and hepatic PtiO2 values were significantly higher in the mild hypothermia group than in the normothermia group during liver ischemia-reperfusion periods (P= 0.032, P= 0.028). Meanwhile, the histopathologic injury of liver induced by ischemia-reperfusion was significantly improved in the mild hypothermia group, compared with that in the normothermia group. CONCLUSION: Mild hypothermia can protect the liver from ischemia-reperfusion injury in pigs.
基金Supported by The Eleventh-five Medical Science Fund of Chengdu Military Command Area,NoMB07011
文摘AIM: To observe the hepatic injury induced by carbon dioxide pneumoperitoneum in rats and to explore its potential mechanism.METHODS: Thirty healthy male SD rats were randomly divided into control group (n = 10), 0 h experimental group (n = 10) and 1 h experimental group (n = 10) after sham operation with carbon dioxide pneumoperitoneum. Histological changes in liver tissue were observed with hematoxylineosin staining. Liver function was assayed with an automatic biochemical analyzer. Concentration of malonyldialdehyde (MDA) and activity of superoxide dismutase (SOD) were assayed by colorimetry. Activity of adenine nucleotide translocator in liver tissue was detected with the atractyloside-inhibitor stop technique. Expression of hypoxia inducible factor-1 (HIF-1) mRNA in liver tissue was detected with in situ hybridization.RESULTS: Carbon dioxide 60 min could induce liver pneumoperitoneum for injury in rats. Alanine aminotransferase and aspartate aminotransferase were 95.7 ± 7.8 U/L and 86.8 ± 6.9 U/L in 0 h experimental group, and 101.4 ± 9.3 U/L and 106.6 ±8.7 U/L in 1 h experimental group. However, no significant difference was found in total billirubin, albumin, and pre-albumin in the three groups. In 0 h experimental group, the concentration of MDA was 9.83 ±2.53 μmol/g in liver homogenate and 7.64 ± 2.19 μmol/g in serum respectively, the activity of SOD was 67.58±9.75 nu/mg in liver and 64.47 ± 10.23 nu/mg in serum respectively. In 1 h experimental group, the concentration of MDA was 16.57±3.45 μmol/g in liver tissue and 12.49 ±4.21 μmol/g in serum respectively, the activity of SOD was 54.29 ±7.96 nu/mg in liver tissue and 56.31 ±9.85 nu/mg in serum respectively. The activity of ANT in liver tissue was 9.52 ± 1.56 in control group, 6.37± 1.33 in 0 h experimental group and 7.2 8±1.45 (10^-9 mol/min per gram protein) in 1 h experimental group, respectively. The expression of HIF-1 mRNA in liver tissue was not detected in control group, and its optical density difference value was 6.14±1.03 in 0 h experimental group and 9.51 ± 1.74 in 1 h experimental group, respectively. CONCLUSION: Carbon dioxide pneumoperitoneum during the sham operation can induce hepatic injury in rats. The probable mechanisms of liver injury include anoxia, ischemia reperfusion and oxidative stress. Liver injury should be avoided during clinical laparoscopic operation with carbon dioxide pneumoperitoneum.
文摘AIM: To compare different preconditioning strategies to protect the liver from ischemia/reperfusion injury focusing on the expression of pro- and anti-apoptotic proteins. Interventions comprised different modes of ischemic preconditioning (IP) as well as pharmacologic pretreatment by α-lipoic acid (LA). METHODS: Several groups of rats were compared: sham operated animals, non-pretreated animals (nt), animals receiving IP (10 rain of ischemia by clamping of the portal triad and 10 min of reperfusion) prior to sustained ischemia, animals receiving selective ischemic preconditioning (IPsel, 10 min of ischemia by selective clamping of the ischemic lobe and 10 rain of reperfusion) prior to sustained ichemia, and animals receiving 500 1μmol α-LA injected i.v. 15 min prior to the induction of 90 min of selective ischemia. RESULTS: Cellular damage was decreased only in the LA group. TUNEL-positive hepatocytes as well as necrotic hepatocyte injury were also decreased only by LA(19 ± 2 vs 10 ± 1, P〈 0.05 and 29 ± 5 vs 12 ± 1, P 〈 0.05). Whereas caspase 3- activities in liver tissue were unchanged, caspase 9- activity in liver tissue was decreased only by LA pretreatment (3.1 ± 0.3 vs 1.8 ± 0.2, P 〈 0.05). Survival rate as the endpoint of liver function was increased after IP and LA pretreatment but not after IPsel. Levels of lipid peroxidation (LPO) in liver tissue were decreased in the IP as well as in the LA group compared to the nt group. Determination of pro- and anti-apoptotic proteins showed a shift towards anti-apoptotic proteins by LA. In contrast, both our IP strategies failed to influence apototic cell death. CONCLUSION: IP, consisting of 10 min of ischemia and 10 min of reperfusion, ischemia/reperfusion injury protects only partly against of the liver prior to 90 min of selective ischemia. IPsel did not influence ischemic tolerance of the liver. LA improved tolerance to ischemia, possibly by downregulation of pro-apoptotic Bax.