PTEN-induced kinase 1-induced dynamin-related protein 1 Ser637 phosphorylation reduces mitochondrial fission and protects against intestinal ischemia reperfusion injury.

BACKGROUND: Intestinal ischemia reperfusion (I/R) occurs in various diseases, such as trauma and intestinal transplantation. Excessive reactive oxygen species (ROS) accumulation and subsequent apoptotic cell death in intestinal epithelia are important causes of I/R injury. PTEN-induced putative kinase 1 (PINK1) and phosphorylation of dynamin-related protein 1 (DRP1) are critical regulators of ROS and apoptosis. However, the correlation of PINK1 and DRP1 and their function in intestinal I/R injury have not been investigated. Thus, examining the PINK1/DRP1 pathway may help to identify a protective strategy and improve the patient prognosis. AIM: To clarify the mechanism of the PINK1/DRP1 pathway in intestinal I/R injury. METHODS: Male C57BL/6 mice were used to generate an intestinal I/R model via superior mesenteric artery occlusion followed by reperfusion. Chiu's score was used to evaluate intestinal mucosa damage. The mitochondrial fission inhibitor mdivi-1 was administered by intraperitoneal injection. Caco-2 cells were incubated in vitro in hypoxia/reoxygenation conditions. Small interfering RNAs and overexpression plasmids were transfected to regulate PINK1 expression. The protein expression levels of PINK1, DRP1, p-DRP1 and cleaved caspase 3 were measured by Western blotting. Cell viability was evaluated using a Cell Counting Kit-8 assay and cell apoptosis was analyzed by TUNEL staining. Mitochondrial fission and ROS were tested by MitoTracker and MitoSOX respectively. RESULTS: Intestinal I/R and Caco-2 cell hypoxia/reoxygenation decreased the expression of PINK1 and p-DRP1 Ser637. Pretreatment with mdivi-1 inhibited mitochondrial fission, ROS generation, and apoptosis and ameliorated cell injury in intestinal I/R. Upon PINK1 knockdown or overexpression in vitro, we found that p-DRP1 Ser637 expression and DRP1 recruitment to the mitochondria were associated with PINK1. Furthermore, we verified the physical combination of PINK1 and p-DRP1 Ser637. CONCLUSION: PINK1 is correlated with mitochondrial fission and apoptosis by regulating DRP1 phosphorylation in intestinal I/R. These results suggest that the PINK1/DRP1 pathway is involved in intestinal I/R injury, and provide a new approach for prevention and treatment.

Ubiquitin-specific protease 22 enhances intestinal cell proliferation and tissue regeneration after intestinal ischemia reperfusion injury.

BACKGROUND: Intestinal ischemia reperfusion (I/R) injury is a serious but common pathophysiological process of many diseases, resulting in a high mortality rate in clinical practice. Ubiquitin-specific protease 22 (USP22) acts as regulator of cell cycle progression, proliferation, and tumor invasion. Depleted USP22 expression has been reported to contribute to arrested cell cycle and disrupted generation of differentiated cell types in crypts and villi. However, the role of USP22 in intestinal damage recovery has not been investigated. Therefore, elucidation of the underlying mechanism of USP22 in intestinal I/R injury may help to improve the tissue repair and patient prognosis in clinical practice. AIM: To investigate the role of USP22 in intestinal cell proliferation and regeneration after intestinal I/R injury. METHODS: An animal model of intestinal I/R injury was generated in male Sprague-Dawley rats by occlusion of the superior mesenteric artery followed by reperfusion. Chiu's scoring system was used to grade the damage to the intestinal mucosa. An in vitro model was developed by incubating rat intestinal epithelial IEC-6 cells in hypoxia/reoxygenation conditions in order to simulate I/R in vivo. siRNA and overexpression plasmid were used to regulate the expression of USP22. USP22, Cyclin D1, and proliferating cell nuclear antigen (PCNA) expression levels were measured by Western blot analysis and immunohistochemistry staining. Cell survival (viability) and cell cycle were evaluated using the Cell Counting Kit-8 and flow cytometry, respectively. RESULTS: USP22 expression was positively correlated with the expression levels of PCNA and Cyclin D1 both in vivo and in vitro, which confirmed that USP22 was involved in cell proliferation and intestinal regeneration after intestinal I/R injury. Decreased levels of Cyclin D1 and cell cycle arrest were observed in the USP22 knockdown group (P < 0.05), while opposite results were observed in the USP22 overexpression group (P < 0.05). In addition, increased expression of USP22 was related to improved intestinal pathology or IEC-6 cell viability after I/R or hypoxia/reoxygenation. These results suggested that USP22 may exert a protective effect on intestinal I/R injury by regulating cell proliferation and facilitating tissue regeneration. CONCLUSION: USP22 is correlated with promoting intestinal cell proliferation and accelerating intestinal tissue regeneration after intestinal I/R injury and may serve as a potential target for therapeutic development for tissue repair during intestinal I/R injury.

Alisol B 23-acetate protects against ANIT-induced hepatotoxity and cholestasis, due to FXR-mediated regulation of transporters and enzymes involved in bile acid homeostasis.

Intrahepatic cholestasis is a clinical syndrome with systemic and intrahepatic accumulation of excessive toxic bile acids that ultimately cause hepatobiliary injury. Appropriate regulation of bile acids in hepatocytes is critically important for protection against liver injury. In the present study, we characterized the protective effect of alisol B 23-acetate (AB23A), a natural triterpenoid, on alpha-naphthylisothiocyanate (ANIT)-induced liver injury and intrahepatic cholestasis in mice and further elucidated the mechanisms in vivo and in vitro. AB23A treatment dose-dependently protected against liver injury induced by ANIT through reducing hepatic uptake and increasing efflux of bile acid via down-regulation of hepatic uptake transporters (Ntcp) and up-regulation of efflux transporter (Bsep, Mrp2 and Mdr2) expression. Furthermore, AB23A reduced bile acid synthesis through repressing Cyp7a1 and Cyp8b1, increased bile acid conjugation through inducing Bal, Baat and bile acid metabolism through an induction in gene expression of Sult2a1. We further demonstrate the involvement of farnesoid X receptor (FXR) in the hepatoprotective effect of AB23A. The changes in transporters and enzymes, as well as ameliorative liver histology in AB23A-treated mice were abrogated by FXR antagonist guggulsterone in vivo. In vitro evidences also directly demonstrated the effect of AB23A on FXR activation in a dose-dependent manner using luciferase reporter assay in HepG2 cells. In conclusion, AB23A produces protective effect against ANIT-induced hepatotoxity and cholestasis, due to FXR-mediated regulation of transporters and enzymes.

Protective effects of icariin-mediated SIRT1/FOXO3 signaling pathway on intestinal ischemia/reperfusion-induced acute lung injury.

Acute lung injury (ALI) is a common complication following intestinal ischemia/reperfusion (I/R) and is a major contributing factor to its high mortality rate. Sirtuin 1 (SIRT1), a NAD+-dependent deacetylase, has been reported to have an important role in apoptosis inhibition, oxidative stress resistance and cell lifespan extension through its deacetylation of forkhead box protein O3 (FOXO3). It has been demonstrated that icariin (ICA), a flavonoid extracted from Epimedium, upregulates SIRT1 expression. The aim of the present study was to examine whether ICA-mediated SIRT1/FOXO3 signaling pathway activation had a protective effect on intestinal I/R-induced ALI. The effects of ICA on intestinal I/R-induced ALI and its regulation of the SIRT1/FOXO3 signaling pathway on intestinal I/R-induced ALI were investigated in rats. The results demonstrated that ICA pretreatment markedly reduced intestinal I/R-induced ALI as indicated by histological alterations, including decreased tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), reduced oxidative stress, acetylated FOXO3 and B-cell lymphoma 2 (Bcl-2)-interacting mediator of cell death levels, and increased glutathione (GSH), GSH peroxidase, SIRT1, manganese superoxide dismutase and Bcl-2 levels in rat lung tissues. Furthermore, ICA pretreatment upregulated SIRT1 expression, which then downregulated FOXO3 acetylation. In conclusion, ICA exhibited significant protective effects in intestinal I/R-induced ALI. The protective effect of ICA may be attributed to the upregulation of SIRT1, which contributed to FOXO3 deacetylation and the modulation of downstream antioxidative and anti-apoptotic factors.

Suppression of the p66shc adapter protein by protocatechuic acid prevents the development of lung injury induced by intestinal ischemia reperfusion in mice.

BACKGROUND: Intestinal ischemia/reperfusion (I/R) causes severe histological injury, reactive oxygen species activation, and cell apoptosis in the lung. In this study, we investigated, using a murine intestinal I/R model, the effect of a polyphenolic compound, protocatechuic acid (PCA), in modulation of ShcA and in protection of the lung from I/R-induced injury. METHODS: Fifty ICR mice were randomly divided into five groups, including a control group, intestinal I/R group, control + PCA group, I/R + PCA low-dose group, and I/R + PCA high-dose group. The I/R and I/R + PCA groups were subjected to mesenteric arterial ischemia for 45 minutes and reperfusion for 90 minutes. The control and control + PCA groups underwent a surgical procedure that included isolation of the superior mesenteric artery without occlusion. In all PCA-pretreated groups, the mice received intraperitoneal PCA administration for three consecutive days. Serum specimens were collected for measuring tumor necrosis factor-α and interleukin 6, while lung tissues were harvested for histopathologic assessment including glutathione (GSH) and GSH peroxidase assay. Lung expression of p66shc, phosphorylated p66shc, manganese superoxide dismutase, caspace-3, and Bcl-xL were determined by Western blotting for protein level and semiquantitative reverse transcription-polymerase chain reaction analysis for mRNA level. RESULTS: PCA pretreatment markedly reduced I/R-induced lung injury as indicated by histological alterations; the decreases in tumor necrosis factor-α, interleukin 6, and caspase-3 expression levels; and the increases in GSH, GSH peroxidase, manganese superoxide dismutase, and Bcl-xL levels in the lung. Moreover, PCA treatment down-regulated p66shc expression and phosphorylation. CONCLUSION: PCA has a significant protective effect in lung injury induced by intestinal I/R. The protective effect of PCA may be attributed to the suppression of p66shc and the modulation of downstream antioxidative/antiapoptotic factors.

Microbial transformation of deoxyandrographolide and their inhibitory activity on LPS-induced NO production in RAW 264.7 macrophages.

A series of analogues of deoxyandrographolide (1) transformed by Cunninghamella blakesleana AS 3.2004 were isolated and identified by spectral methods including 2D NMR. Among them, 3-oxo-17,19-dihydroxy-7,13-ent-labdadien-15,16-olide (9), 3-oxo-19-hydroxy-1,13-ent-labdadien-15,16-olide (16), 3-oxo-1ß-hydroxy-14-deoxy-andrographolide (17) and 3-oxo-2ß-hydroxy-14-deoxyandrographolide (18) are new compounds. And their structure-activity relationships (SAR) of inhibitory activity on LPS-induced NO production in RAW 264.7 macrophage cells were also discussed.

Novel microbial transformation of resibufogenin by Fusarium solani.

In this paper, microbial transformation of resibufogenin by Fusarium solani AS 3.1829 was investigated, and five transformed products were isolated and identified as 3-ketone-resibufogenin (2), 3-one-cyclic 3-(1,2-dimethyl-1,2-ethanediylacetal)-resibufogenin (3), 3-dimethoxyl-resibufogenin (4), 3-epi-resibufogenin (5), and 3-epi-15α-hydroxy-7ßH-bufalin (6), respectively. Among them, 3, 4, and 6 are new compounds, and the rare double oxidization of C-3 was reported. In addition, the cytotoxicities of transformed products were also investigated.

Microbial transformation of deoxyandrographolide by Alternaria alternata AS 3.4578.

Biotransformation of deoxyandrographolide (1) by Alternaria alternata AS 3.4578 gave five derivatives identified by spectral methods including 2D NMR as the known dehydroandrographolide (2) and 9beta-hydroxy-dehydroandrographolide (3) and the new compounds 9beta-hydroxy-deoxyandrographolide (4), 3alpha,17,19-trihydroxy-8,13-ent-labdadien-15,16-olide (5) and 3-oxo-9beta-hydroxy-deoxyandrographolide (6).

Inhibition of Rho kinase by fasudil hydrochloride attenuates lung injury induced by intestinal ischemia and reperfusion.

AIM: The aim of this study is to evaluate the role of Rho-kinase in the pathogenesis of lung injury induced by intestinal ischemia/reperfusion (I/R) and the preconditioning effects of fasudil hydrochloride. The novel therapeutic approach of using Rho-kinase inhibitors in the treatment of intestinal I/R is introduced. METHODS: Sprague-Dawley (SD) rats were divided into 4 groups: intestinal I/R group, two fasudil pretreatment groups (7.5 mg/kg and 15 mg/kg), and controls. Intestinal and lung histopathology was evaluated; myeloperoxidase (MPO) and superoxide dismutase (SOD) levels in lung parenchyma were determined. Serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were measured. eNOS and P-ERM expression were measured by Western Blot. RESULTS: Lung and intestinal injury were induced by intestinal I/R, characterized by histological damage and a significant increase in BALF protein. Compared to controls, serum TNF-α, IL-6, and lung MPO activity increased significantly in the I/R group, while SOD activity decreased. A strongly positive P-ERM expression was observed, while eNOS expression was weak. After fasudil administration, injury was ameliorated. Serum TNF-α, IL-6, lung MPO and P-ERM expression decreased significantly as compared to the I/R group, while SOD activity and eNOS expression increased significantly. SIGNIFICANCE: Rho-kinase plays a key role in the pathogenesis of lung injury induced by intestinal I/R. The inhibition of the Rho-kinase pathway by fasudil hydrochloride may prevent lung injury.

Protective effect of carnosol on lung injury induced by intestinal ischemia/reperfusion.

PURPOSE: Carnosol is a phenolic diterpene that has potent antioxidant and anti-inflammatory activities. The purpose of this study was to investigate the preconditioning effects of carnosol on lung injury induced by intestinal ischemia/reperfusion (II/R). METHODS: Rats were divided into control, II/R, and carnosol groups. The II/R model was established by clamping the superior mesenteric artery for 1 h and reperfusion at 2, 4, and 6 h after ischemia. The carnosol group received 3 mg/kg carnosol intraperitoneally 1 h before the operation. The rats were then euthanized, and blood and lung specimens were obtained for analysis. RESULTS: The II/R induced lung injury, characterized by histological changes and significant increasing of bronchoalveolar lavage fluid protein. The activity of lung tissue superoxide was weakened, the tissue myeloperoxidase activity and serum interleukin-6 level increased significantly in II/R groups. A strong positive expression of lung intercellular adhesion molecule-1 (ICAM-1) and nuclear factor kappa B (NF-kappaB) were observed. Pretreatment with carnosol markedly reduced lung injury by increasing the tissue superoxide activity and decreasing the myeloperoxidase activity and interleukin-6 level, which was parallel to the decreased expression of ICAM-1 and NF-kappaB. CONCLUSION: Carnosol was able to ablate lung injury induced by II/R, partly attributed to the inhibition of NF-kappaB activation.

Preparative separation of four major bufadienolides from the Chinese traditional medicine, Chansu, using high-speed counter-current chromatography.

A preparative, high-speed, counter-current chromatographic (HSCCC) method for the isolation and purification of bufadienolides from Chansu was successfully developed by using stepwise elution with a two-phase solvent system composed of n-hexane: chloroform: methanol: water (4:1:2.5:5 and 4:1:4:5, v/v). A total of 7.5 mg of cinobufotalin (1), 8.0 mg of bufalin (2), 14.0 mg of cinobufagin (3) and 9.5 mg of resibufogenin (4) were obtained in a one-step separation from 80 mg of the crude extract with purities of 93.2%, 98.7%, 99.2%, and 99.4%, respectively. The chemical structures were determined from 1H NMR and 13C NMR spectroscopic data.

Sulforaphane protects liver injury induced by intestinal ischemia reperfusion through Nrf2-ARE pathway.

AIM: To investigate the effect of sulforaphane (SFN) on regulation of NF-E2-related factor-2 (Nrf2)-antioxidant response element (ARE) pathway in liver injury induced by intestinal ischemia/reperfusion (I/R). METHODS: Rats were divided randomly into four experimental groups: control, SFN control, intestinal I/R and SFN pretreatment groups (n = 8 in each group). The intestinal I/R model was established by clamping the superior mesenteric artery for 1 h and 2 h reperfusion. In the SFN pretreatment group, surgery was performed as in the intestinal I/R group, with intraperitoneal administration of 3 mg/kg SFN 1 h before the operation. Intestine and liver histology was investigated. Serum levels of aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were measured. Liver tissue superoxide dismutase (SOD), myeloperoxidase (MPO), glutathione (GSH) and glutathione peroxidase (GSH-Px) activity were assayed. The liver transcription factor Nrf2 and heme oxygenase-1 (HO-1) were determined by immunohistochemical analysis and Western blotting analysis. RESULTS: Intestinal I/R induced intestinal and liver injury, characterized by histological changes as well as a significant increase in serum AST and ALT levels (AST: 260.13 +/- 40.17 U/L vs 186.00 +/- 24.21 U/L, P < 0.01; ALT: 139.63 +/- 11.35 U/L vs 48.38 +/- 10.73 U/L, P < 0.01), all of which were reduced by pretreatment with SFN, respectively (AST: 260.13 +/- 40.17 U/L vs 216.63 +/- 22.65 U/L, P < 0.05; ALT: 139.63 +/- 11.35 U/L vs 97.63 +/- 15.56 U/L, P < 0.01). The activity of SOD in the liver tissue decreased after intestinal I/R (P < 0.01), which was enhanced by SFN pretreatment (P < 0.05). In addition, compared with the control group, SFN markedly reduced liver tissue MPO activity (P < 0.05) and elevated liver tissue GSH and GSH-Px activity (P < 0.05, P < 0.05), which was in parallel with the increased level of liver Nrf2 and HO-1 expression. CONCLUSION: SFN pretreatment attenuates liver injury induced by intestinal I/R in rats, attributable to the antioxidant effect through Nrf2-ARE pathway.

Efficient isolation and purification of five products from microbial biotransformation of cinobufagin by high-speed counter-current chromatography.

An efficient separation method of using high-speed counter-current chromatography was successfully established to directly purify cytotoxic transformed products of cinobufagin by Cordyceps militaris. The two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (4:6:3:4, v/v) was used in high-speed counter-current chromatography. A total of 9 mg of 4beta,12alpha-dihydroxyl-cinobufagin (1), 15 mg of 12beta-hydroxyl-cinobufagin (2), 8 mg of 5beta-hydroxyl-cinobufagin (3), 12 mg of deacetylcinobufagin (4) and 6 mg of 3-keto-cinobufagin (5) were obtained in a one-step separation from 400 mg of the crude extract with purity of 98.7, 97.2, 90.6, 99.1 and 99.4%, respectively, as determined by HPLC. Their chemical structures were identified on the basis of (1)H-NMR and (13)C-NMR technology. All products (1-5) showed the potent activities against human carcinoma cervicis (Hela) and malignant melanoma (A375) cells in vitro.

Structural determination of two new triterpenoids biotransformed from glycyrrhetinic acid by Mucor polymorphosporus.

Five hydroxylated derivatives of glycyrrhetinic acid by Mucor polymorphosporus were isolated. Among them, 6beta, 7beta-dihydroxyglycyrrhentic acid (2) and 27-hydroxyglycyrrhentic acid (3) are new compounds. Their chemical structures were identified by spectral methods including 2D-NMR.

Prophylaxis with carnosol attenuates liver injury induced by intestinal ischemia/reperfusion.

AIM: To investigate the possible protective effects of carnosol on liver injury induced by intestinal ischemia reperfusion (I/R). METHODS: Rats were divided randomly into three experimental groups: sham, intestinal I/R and carnosol treatment (n = 18 each). The intestinal I/R model was established by clamping the superior mesenteric artery for 1 h. In the carnosol treatment group, surgery was performed as in the intestinal I/R group, with intraperitoneal administration of 3 mg/kg carnosol 1 h before the operation. At 2, 4 and 6 h after reperfusion, rats were killed and blood, intestine and liver tissue samples were obtained. Intestine and liver histology was investigated. Serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and interleukin (IL)-6 were measured. Liver tissue superoxide dismutase (SOD) and myeloperoxidase (MPO) activity were assayed. The liver intercellular adhesion molecule-1 (ICAM-1) and nuclear factor kappaB (NF-kappaB) were determined by immunohistochemical analysis and western blot analysis. RESULTS: Intestinal I/R induced intestine and liver injury, characterized by histological changes, as well as a significant increase in serum AST and ALT levels. The activity of SOD in the liver tissue decreased after I/R, which was enhanced by carnosol pretreatment. In addition, compared with the control group, carnosol markedly reduced liver tissue MPO activity and serum IL-6 level, which was in parallel with the decreased level of liver ICAM-1 and NF-kappaB expression. CONCLUSION: Our results indicate that carnosol pretreatment attenuates liver injury induced by intestinal I/R, attributable to the antioxidant effect and inhibition of the NF-kappaB pathway.

Proteasome inhibitor lactacystin ablates liver injury induced by intestinal ischaemia-reperfusion.

1. The aim of the present study was to investigate the role of proteasome in the pathogenesis of liver injury induced by intestinal ischaemia-reperfusion (I/R) and the effect of the proteasome inhibitor lactacystin on neutrophil infiltration, intracellular adhesion molecule (ICAM)-1 and nuclear factor (NF)-kappaB expression in the liver tissues of rats. 2. Thirty-two Wistar rats were randomly divided into four groups (n = 8 in each group) as follows: (i) a control, sham-operated group; (ii) an I/R group subjected to 1 h intestinal ischaemia and 4 h reperfusion; (iii) a group pretreated with 0.2 mg/kg lactacystin 1 h before intestinal I/R; and (iv) a group pretreated with 0.6 mg/kg lactacystin 1 h before intestinal I/R. Liver and intestine histology were observed. Serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH), as well as 20S proteasome activity in circulating white blood cells, were measured. Myeloperoxidase (MPO) activity in liver tissues and the immunohistochemical expression of liver NF-kappaB and ICAM-1 were assayed. In addition, a western blot of liver NF-kappaB was performed. 3. Compared with the sham-operated control group, liver and intestine injury was induced by intestinal I/R, characterized as histological damage including oedema, haemorrhage and infiltration by inflammatory cells, as well as a significant increase in serum AST (365 +/- 121 vs 546 +/- 297 IU/L, respectively; P < 0.05), ALT (65 +/- 23 vs 175 +/- 54 IU/L, respectively; P < 0.01) and LDH levels (733 +/- 383 vs 1434 +/- 890 IU/L, respectively; P < 0.05). Compared with the control group, MPO activity in the liver tissues increased significantly in the I/R group (2.05 +/- 0.69 vs 3.42 +/- 1.11 U/g, respectively; P < 0.05). Strong positive expression of liver ICAM-1 and NF-kappaB p65 was observed. 4. Compared with the intestinal I/R group, administration of 0.6 mg/kg lactacystin markedly reduced 20S proteasome activity in circulating white blood cells (15.47 +/- 4.00 vs 2.07 +/- 2.00 pmol 7-amino-4-methylcoumarin (AMC)/s per mg, respectively; P < 0.01) and ameliorated liver injury, which was demonstrated by decreased levels of serum AST (546 +/- 297 vs 367 +/- 86 IU/L, respectively; P < 0.05), ALT (175 +/- 54 vs 135 +/- 26 IU/L, respectively; P < 0.05) and LDH (1434 +/- 890 vs 742 +/- 218 IU/L, respectively; P < 0.05) and a reduced liver pathological score (2.13 +/- 0.64 vs 1.25 +/- 0.46, respectively; P < 0.01). Compared with the intestinal I/R group, MPO activity in liver tissues decreased significantly following lactacystin pretreatment (3.42 +/- 1.11 vs 2.58 +/- 0.61 U/g, respectively; P < 0.05) and the expression of liver NF-kappaB and ICAM-1 was markedly ameliorated. 5. The present study reveals that the proteasome inhibitor lactacystin ablates liver injury induced by intestinal I/R. One possible mechanism responsible for this effect is the inhibition of enhanced ICAM-1 and neutrophil infiltration by inhibition of NF-kappaB activity. The results suggest the feasibility of using proteasome inhibitor clinically in the treatment of intestinal I/R.

Protection of Veratrum nigrum L. var. ussuriense Nakai alkaloids against ischemia-reperfusion injury of the rat liver.

AIM: To investigate the protective effects and possible mechanisms of Veratrum nigrum L.var. ussuriense Nakai alkaloids (VnA) on hepatic ischemia/reperfusion (I/R) injury in rats. METHODS: Forty male Wistar rats were randomly divided into four experimental groups (n = 10 in each): (A) Control group (the sham operation group); (B) I/R group (pretreated with normal saline); (C) Small-dose (10 microg/kg) VnA pretreatment group; (D) Large-dose (20 microg/kg) VnA pretreatment group. Hepatic ischemia/reperfusion (Hepatic I/R) was induced by occlusion of the portal vein and the hepatic artery for 90 min, followed by reperfusion for 240 min. The pretreatment groups were administered with VnA intraperitoneally, 30 min before surgery, while the control group and I/R group were given equal volumes of normal saline. Superoxide dismutase (SOD) activity, myeloperoxidase (MPO) activity and nitric oxide (NO) content in the liver tissue at the end of reperfusion were determined and liver function was measured. The expression of intercellular adhesion molecule-1 (ICAM-1) and E-selectin (ES) were detected by immunohistochemical examinations and Western blot analyses. RESULTS: The results showed that hepatic I/R elicited a significant increase in the plasma levels of alanine aminotransferase (ALT: 74.53 +/- 2.58 IU/L vs 1512.54 +/- 200.76 IU/L, P < 0.01) and lactic dehydrogenase (LDH: 473.48 +/- 52.17 IU/L vs 5821.53 +/- 163.69 IU/L, P < 0.01), as well as the levels of MPO (1.97 +/- 0.11 U/g vs 2.57 +/- 0.13 U/g, P < 0.01) and NO (69.37 +/- 1.52 micromol/g protein vs 78.39 +/- 2.28 micromol/g protein, P < 0.01) in the liver tissue, all of which were reduced by pretreatment with VnA, respectively (ALT: 1512.54 +/- 200.76 IU/L vs 977.93 +/- 89.62 IU/L, 909.81 +/- 132.76 IU/L, P < 0.01, P < 0.01; LDH: 5821.53 +/- 163.69 IU/L vs 3015.44 +/- 253.01 IU/L, 2448.75 +/- 169.4 IU/L, P < 0.01, P < 0.01; MPO: 2.57 +/- 0.13 U/g vs 2.13 +/- 0.13 U/g, 2.07 +/- 0.05 U/g, P < 0.01, P < 0.01; NO: 78.39 +/- 2.28 micromol/g protein vs 71.11 +/- 1.73 micromol/g protein, 68.58 +/- 1.95 micromol/g protein, P < 0.05, P < 0.01). The activity of SOD (361.75 +/- 16.22 U/mg protein vs 263.19 +/- 12.10 U/mg protein, P < 0.01) in the liver tissue was decreased after I/R, which was enhanced by VnA pretreatment (263.19 +/- 12.10 U/mg protein vs 299.40 +/- 10.80 U/mg protein, 302.09 +/- 14.80 U/mg protein, P < 0.05, P < 0.05). Simultaneously, the histological evidence of liver hemorrhage, polymorphonuclear neutrophil infiltration and the overexpression of ICAM-1 and E-selectin in the liver tissue were observed, all of which were attenuated in the VnA pretreated groups. CONCLUSION: The results demonstrate that VnA pretreatment exerts significant protection against hepatic I/R injury in rats. The protective effects are possibly associated with enhancement of antioxidant capacity, reduction of inflammatory responses and suppressed expression of ICAM-1 and E-selectin.

Proteasome inhibition attenuates lung injury induced by intestinal ischemia reperfusion in rats.

The aim of this study is to investigate the role of proteasome in the pathogenesis of lung injury induced by intestinal ischemia/reperfusion (I/R) by examining the effect of the proteasome inhibitor lactacystin on neutrophil infiltration, intracellular adhesion molecule-1 (ICAM-1) expression and nuclear factor kappa B (NF-kappaB) activation. Thirty-two Wistar rats were divided into (1) control, (2) intestinal I/R, (3) 0.2 mg/kg lactacystin pretreated, and (4) 0.6 mg/kg lactacystin pretreated groups (n=8). Injuries in lung and intestine were induced by intestinal I/R, and were characterized by histological edema, hemorrhage and infiltration of inflammatory cells. The results showed a significant increase in serum creatine kinase B (CK-B) and lung water content in intestine and lung injuries. As compared with the control group, the myeloperoxidase (MPO) activity in intestine and lung as well as the serum TNF-alpha level increased significantly in intestinal I/R group. Simultaneously, expression of ICAM-1 and NF-kappaB p65 was also observed in the I/R group. Pre-treatment with lactacystin markedly reduced 20S proteasome activity in circulating white blood cells and ameliorated intestine and lung injuries. These results demonstrated that the proteasome participates in the pathogenesis of lung injury induced by intestinal I/R. Lactacystin as a proteasome inhibitor can prevent this kind of injury by decreasing ICAM-1 and TNF-alpha production via the inhibition of NF-kappaB activation.

Effect of nuclear factor kappa B on intercellular adhesion molecule-1 expression and neutrophil infiltration in lung injury induced by intestinal ischemia/reperfusion in rats.

AIM: To investigate the role of nuclear factor kappa B (NF-kappaB) in the pathogenesis of lung injury induced by intestinal ischemia/reperfusion (I/R), and its effect on intercellular adhesion molecule-1 (ICAM-1) expression and neutrophil infiltration. METHODS: Twenty-four Wistar rats were divided randomly into control, I/R and pyrrolidine dithiocarbamate (PDTC) treatment groups, n=8 in each. I/R group and PDTC treatment group received superior mysenteric artery (SMA) occluding for 1 h and reperfusion for 2 h. PDTC group was administrated with intraperitoneal injection of 2% 100 mg/kg PDTC 1 h before surgery. Lung histology and bronchia alveolus lung fluid (BALF) protein were assayed. Serum IL-6, lung malondialdehyde (MDA) and myeloperoxidase (MPO) as well as the expression level of NF-kappaB and ICAM-1 were measured. RESULTS: Lung injury induced by intestinal I/R, was characterized by edema, hemorrhage and neutrophil infiltration as well as by the significant rising of BALF protein. Compared to control group, the levels of serum IL-6 and lung MDA and MPO increased significantly in I/R group (P=0.001). Strong positive expression of NF-kappaB p65 and ICAM-1 was observed. After the administration of PDTC, the level of serum IL-6, lung MDA and MPO as well as NF-kappaB and ICAM-1 decreased significantly (P<0.05) when compared to I/R group. CONCLUSION: The activation of NF-kappaB plays an important role in the pathogenesis of lung injury induced by intestinal I/R through upregulating the neutrophil infiltration and lung ICAM-1 expression. PDTC as an inhibitor of NF-kappaB can prevent lung injury induced by intestinal I/R through inhibiting the activity of NF-kappaB.

Protective effect of pyrrolidine dithiocarbamate on liver injury induced by intestinal ischemia-reperfusion in rats.

BACKGROUND: The nuclear translocation of transcription factors may be a critical factor in the intracellular pathway involved in ischemia/reperfusion (I/R) injury. The aim of the study was to evaluate the role of nuclear factor-kappa B (NF-kappaB) in the pathogenesis of liver injury induced by intestinal ischemia/reperfusion (IIR) and to investigate the effect of pyrrolidine dithiocarbamate (PDTC) on this liver injury. METHODS: Male Wistar rats were divided randomly into three experimental groups (8 rats in each): sham operation group (control group); intestinal/reperfusion group (I/R group): animals received 1-hour of intestinal ischemia and 2-hour reperfusion; and PDTC treatment group (PDTC group): animals that received I/R subject to PDTC treatment (100 mg/kg). The histological changes in the liver and intestine were observed, and the serum levels of tumor necrosis factor-alpha (TNF-alpha), alanine aminotransferase (ALT), aspartate aminotransferase (AST), liver superoxide dismutase (SOD), and nitrite/nitrate (NO) were measured. The immunohistochemical expression and Western blot analysis of liver NF-kappaB and intercellular adhesion molecule-1 (ICAM-1) were observed. RESULTS: IIR induced liver injury characterized by the histological changes of liver edema, hemorrhage, polymorphonuclear neutrophil (PMN) infiltration, and elevated serum levels of AST and ALT. The serum TNF-alpha level was significantly higher than that of the control group (P<0.01) and a high level of liver oxidant product was observed (P<0.01). These changes were parallel to the positive expression of NF-kappaB and ICAM-1. After the administration of PDTC, the histological changes after liver injury were improved; the levels of SOD and NO in the liver were elevated and reduced, respectively (P<0.01). The expressions of ICAM-1 and NF-kappaB in the liver were weakened (P<0.01). CONCLUSION: NF-kappaB plays an important role in the pathogenesis of liver injury induced by IIR. PDTC, an agent known to inhibit the activation of NF-kappaB, can reduce and prevent this injury.