Pyrrolidine dithiocarbamate provides protection against hypothermic preservation and transplantation injury in the rat liver: the role of heme oxygenase-1

BACKGROUND: Pyrrolidine dithiocarbamate (PDTC) represents a class of antioxidants and is a potent inducer of the heme oxygenase-1 (HO-1) gene and an inhibitor of nuclear factor-kappa B (NF-kappa B). We examined the impact of PDTC preconditioning against cold ischemia and reperfusion injury in the rat liver. METHODS: Lewis rats were treated subcutaneously with saline or PDTC solution 24 hours before harvesting. Some animals pretreated with PDTC were also given zinc protoporphyrin IX intravenously immediately after reperfusion. HO-1 expression and enzyme activity in liver tissues were analyzed at different time points after each treatment. After transplantation of 24-hour preserved livers, serum levels of transaminases and gene expression of tumor necrosis factor-alpha, interleukin-1 beta, and NF-kappa B were measured. Animal survival and cellular viability were monitored. RESULTS: HO-1 gene expression and protein synthesis were enhanced in PDTC-treated livers, leading to increased enzyme activity (P <.05). The PDTC treatment group showed lower transaminase levels (P <.05), lower cytokine and NF-kappa B messenger RNA expression (P <.05), and fewer nonviable cells (P <.05) than did the control group, whereas these PDTC effects were abolished with zinc protoporphyrin injection after reperfusion (P <.05). The best animal survival rate was observed in the PDTC group (P <.05). CONCLUSION: PDTC preconditioning reduces inflammatory responses during reperfusion. PDTC appears to exert this protective effect by induction of an antioxidative stress protein and inhibition of proinflammatory cytokines.     

Involvement of nuclear factor-kappa B on corticosterone- induced rat Leydig cell apoptosis

Aim:To investigate the activation of nuclear factor-kappa B(NF-kappa B)and its function in glucocorticoid-inducedLeydig cell apoptosis.Methods:The Leydig cells were isolated from male Sprague-Dawley rats(90 days of age)andwere incubated with corticosterone(CORT,glucocorticoid in rat)for 6 h,12 h and 24 h,respectively.The P65subunit of NF-kappa B(NF-kappa B/P65)in nuclei and the inhibitor of NF-kappa B(Ikappa B)in cytoplasm wereanalyzed by Western-blotting.The Leydig cells were treated with anti-Fas antibody for 3 h followed by Westernblotting to assay the changes of NF-kappa B/P65 in nuclei and in cytoplasm.The role of NF-kappa B in CORT-induced Leydig cell apoptosis was evaluated by observing the effects of NF-kappa B/P65 overexpression and inhibit-ing activation of NF-kappa B by 100μmol/L Pyrrolidine dithiocarbamate(PDTC)on this apoptosis.Results:Thetreatment of Leydig cells with CORT increased the levels of NF-kappa B/P65 in nuclei and decreased the levels ofIkappa B in cytoplasm.Following the Leydig cells were treated with anti-Fas antibody,the levels of NF-kappaB/P65was increased in nuclei and decreased in cytoplasm.The CORT-induced Leydig cell apoptosis was inhibited byoverexpressed NF-kappaB/P65 and was enhanced by incubation with PDTC.Conclusion:NF-kappa B is activatedby increased FasL/Fas in CORT-induced Leydig cell apoptosis.NF-kappa B may play an anti-apoptotic role in thisapoptosis.(Asian J Androl 2006 Nov;8:693-702)     

Inhibition of nuclear factor-kappa B activation reduces glycerol-induced renal injury

BACKGROUND: Glycerol injection induces acute tubular necrosis that can progress to interstitial fibrosis. The oxidative stress seen in glycerol-treated animals can activate the nuclear factor kappa B (NF-kappa B) system. The aim of this study was to investigate the expression of NF-kappa B and mitogen-activated protein kinases (MAPKs) in the renal cortex and to determine its relationship with structural and functional renal changes in rats treated with glycerol or glycerol plus pyrrolidine dithiocarbamate (PDTC), a nonspecific NF-kappa B inhibitor with antioxidant properties. METHODS: Male Wistar rats were injected intramuscularly with 8 ml/kg of either 50% glycerol (n=22), glycerol+PDTC (n=25) or 0.15 M saline (n=10). The rats were killed, and the kidneys removed at 5 or 30 days after injection. mmunohistochemical results were scored according to the extent of staining. Interstitial lesions were evaluated through morphometry. Lipid peroxidation was estimated by measuring malondialdehyde in urine samples from control rats and glycerol-injected rats. RESULTS: By postinjection day 5, glycerol-only treated rats presented transitory increases in plasma creatinine levels, as well as in fractional excretion of sodium and potassium (p<0.001), which were attenuated in glycerol+PDTC treated rats (p<0.05). Cortical expression of macrophages and NF-kappa B was greater in glycerol-treated rats than in controls (p<0.001). Glycerol-induced histological nd immunohistochemical changes were attenuated by the addition of PDTC (p<0.001), which also reduced the glycerol-induced increase in urinary malondialdehyde (MDA) levels (p<0.05). CONCLUSIONS: We conclude that PDTC attenuates glycerol-induced renal injury by reducing NF-kappa B expression and decreasing lipid peroxidation in the renal cortex.     

RelA is required for IL-1beta stimulation of Matrix Metalloproteinase-1 expression in chondrocytes

OBJECTIVE: Interleukin-1beta (IL-1beta) stimulates collagenase-1 (Matrix Metalloproteinase-1 (MMP-1)) expression in articular chondrocytes, leading to cleavage of type II collagen and irreversible cartilage degradation. The nuclear factor-kappa B (NF-kappaB) pathway is potently activated in IL-1beta-stimulated cells and has been implicated as an intermediate in MMP-1 gene expression. However, the roles of individual NF-kappaB family members during IL-1beta-induced MMP-1 gene expression have not been defined. RESULTS: To address the relationship between the NF-kappaB pathway and MMP-1 gene activation in chondrocytes, primary cultured human articular chondrocyte cultures (HAC) and SW-1353 cells were stimulated with IL-1beta over a 24-h time course and MMP-1, NF-kappaB1, NF-kappaB2 and RelA gene expression was assayed. IL-1beta-induced MMP-1 expression was comparable in HAC and SW-1353 cells both temporally and quantitatively. MMP-1 gene expression was mirrored by increases in NF-kappaB gene expression, and inhibition of NF-kappaB nuclear translocation with dominant-negative IkappaBalpha reduced IL-1beta-dependent MMP-1 gene expression. IL-1beta activated the NF-kappaB pathway in chondrocytes, both through phosphorylation and transient degradation of IkappaBalpha, as well as through sustained phosphorylation of RelA. Small inhibitory RNAs (siRNA) specific for RelA resulted in significant reduction of MMP-1 mRNA, whereas siRNA for NF-kappaB1 and NF-kappaB2 augmented IL-1beta-induced MMP-1 expression. CONCLUSIONS: Our data demonstrate that IL-1beta activation of the NF-kappaB pathway is required for IL-1beta induction of MMP-1 in chondrocytes and that RelA can work independently of NF-kappaB1 or NF-kappaB2 to activate this gene expression program.     

大鼠被动型海曼肾炎肾脏p21及增殖细胞核抗原的表达及意义

目的研究大鼠被动型海曼肾炎（passive heymannn ephritis,PHN）肾脏p21及增殖细胞核抗原（proliferating cell nuclear antigen．PCNA）的表达及其与PHN发病的关系。方法32只SD大鼠随机分为PHN模型组及正常对照组,定期检测24h尿蛋白定量及血液生化指标,同时取肾皮质标本切片行光镜、免疫荧光及电镜检查,采用S越3C法分别检测肾脏p21及PCNA的表达。结果PHN模型组大鼠出现大量蛋白尿及高胆同醇血症,肾小球内可见免疫复合物沿毛细血管壁沉积,电镜下见。肾小球上皮下电子致密物沉积。免疫组织化学显示,PCNA及p21在PHN组肾小球内的表达均较对照组明显增高（P〈0．05）。结论PHN模型中肾小球足细胞显示一定的低增生能力,可能部分由于补体损伤后p21的水平上调所致,它对促进PHN后期病程进展及膜性肾病的预后具有意义。     

Increased expression of NF-kappa B subunits in human pancreatic cancer cells

BACKGROUND: Activation of NF-kappa B-dependent antiapoptotic genes may factor in the chemoresistance of pancreatic cancer. It is not known whether NF-kappa B subunit composition changes during oncogenesis and regulates overall NF-kappa B activation. We compared the relative expression of NF-kappa B subunits with nuclear activation of p65 between variably differentiated pancreatic cancer cells. MATERIALS AND METHODS: Proliferating human pancreatic cancer cells (PANC-1, BxPC-3) and nonmalignant intestinal cells (FHS 74 Int) were harvested. Baseline expression of NF-kappa B subunits (p65, p52, p50, c-Rel) and its inhibitor I kappa B-alpha were determined by Western blot. Nuclear NF-kappa B p65 activity was measured by ELISA. Results were analyzed by ANOVA (P < 0.05) and Tukey's HSD for pairwise comparisons when appropriate (P < 0.05). RESULTS: Constitutive expression of NF-kappa B subunits was detected in proliferating, intestinal cells (FHS 74 Int). Both cytoplasmic (I kappa B-alpha, p50, p52, p65) and nuclear (p50, p52, p65, c-Rel) NF-kappa B subunits were significantly increased in both PANC-1 and BxPC-3 cells compared to FHS 74 Int. While nuclear p65 subunit levels were similarly elevated, actual p65 activity was only significantly greater in PANC-1 cells compared to either BxPC-3 or FHS 74 Int (P < 0.05). CONCLUSIONS: Compared to nonmalignant proliferating intestinal cells, these pancreatic cancer cell lines have increased levels of NF-kappa B subunits. Actual nuclear NF-kappa B activity, however, appears to correlate more with degree of tumor differentiation than with NF-kappa B subunit expression.     

抑制核因子κ B活化对高脂饮食大鼠主动脉内皮细胞的保护作用

目的观察吡咯烷二硫代氨基甲酸盐(PDTC)对高脂饮食模型大鼠主动脉内皮细胞的影响并探讨其机制。方法 SD大鼠18只随机分为高脂对照组、PDTC干预高脂组、空白对照组。12周后取主动脉行电镜检查,以电泳迁移率变动分析法(EMSA)检测核因子κB(NF-κB)活性,放射免疫法测定血清肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)水平,酶联免疫吸附实验测量可溶性血栓调节蛋白(sTM)水平。结果高脂对照组的血管内皮细胞存在明显的崩解现象,而PDTC干预组损伤轻微。PDTC干预高脂组sTM水平显著高于空白对照组,低于高脂对照组(P0.05)。与空白对照组相比,高脂对照组主动脉NF-κB活性、血清TNF-α和IL-6水平显著升高,PDTC干预高脂组也有升高但明显低于高脂对照组(P0.05)。NF-κB活性与TNF-α、IL-6、sTM水平呈正相关(P0.05)。结论 PDTC可以通过抑制高脂饮食模型大鼠的主动脉中NF-κB的活化、减轻过度的炎症反应而发挥保护内皮细胞的作用。     

Role of podocyte autophagy in passive Heymann nephritis

Objective To investigate the role of autophagy in podocyte damage, and the intracellular mechanism of autophagy activation through passive Heymann nephritis (PHN) animal model. Methods Male Sprague-Dawley rats (n=40) were studied on day 0, 2, 4, 7, and 21 after induction of PHN by injection of anti-Fx1A. Podocyte morphology and autophagosomes were observed by transmission electron microscopy. Podocyte numerical density was estimated by Weibel-Gomez method. Cell apoptosis was detected by TUNEL assay and caspase-3 immunohistochemical staining. Expressions of autophagy markers and endoplasmic reticulum stress (ERS)-associated proteins were analyzed by Western blotting. Results (1) In PHN rats, immunohistochemical staining showed that C5b-9 deposited along glomerular basement membrane on day 4 to day 21. Small subepithelial electron-dense deposits and a part of foot process fusion were detected in the glomerulus of PHN rats on day 4 by transmission electron microscope, and podocyte damage was aggravated on day 21. Furthermore, compared with control, the urinary protein levels of PHN rats began to increase on day 3, and reached the top on day 21 [(50.6±6.0) mg/24 h]. (2) The number of podocytes significantly decreased in PHN rats compared with control group on day 21(P＜0.05). (3) In PHN rats, apoptotic podocytes were found by caspase-3 immunohistochemical staining and TUNEL assay on day 21. (4) The expression of autophagy marker LC3Ⅱwas markedly increased on day 7 and 21, but down-regulated on day 21 compared with day 7. Moreover, accumulated autophagosomes in podocytes were detected on day 7 and 21 by transmission electron microscope. (5) The level of GRP78 was significantly increased on day 2 and 7 but reduced to baseline on day 21. At the same time, the downstream pathways (ATF6α, p-PERK and p-JNK) of unfolded protein response were also up-regulated in the early process of PHN and down-regulated later. Conclusions Autophagy is an important way to protect against immune-mediated podocyte injury in membranous nephropathy. Autophagy activation is mainly related to endoplasmic reticulum stress induced by complement attack. This provides an important basis for a thorough understanding of the role of autophagy in the process of podocyte damage and the pathogenesis of membranous nephropathy.     

Cytokine gene expression in Adriamycin nephropathy: effects of antioxidant nuclear factor kappaB inhibitors in established disease

BACKGROUND/AIM: Inhibition of nuclear factor kappaB with the antioxidant pyrrolidine dithiocarbamate (PDTC) reduced tubulointerstitial injury in Adriamycin nephropathy (AN), whereas N-acetylcysteine (NAC) was ineffective. Here we hypothesize that PDTC reduces the renal cortical expression of nuclear factor kappaB dependent cytokines in AN. METHODS: Male Wistar rats received a single intravenous injection of doxorubicin hydrochloride (7.5 mg/kg). NAC (150 mg/kg twice daily i.p.), PDTC (50 mg/kg twice daily i.p.), or vehicle were commenced on day 14 and continued until day 30. RESULTS: On day 30, mRNAs of selected cytokines were increased in AN (TNF-alpha 3.4-fold, MCP-1 5.1-fold, IL-10 2.7-fold, TGF-beta1 3.5-fold, all p < 0.05) as determined by RT-PCR. PDTC reduced IL-10 and TGF-beta1 mRNAs (p < 0.05), whereas the upregulation of MCP-1 and TNF-alpha mRNAs was not affected. In contrast, NAC increased TNF-alpha and IL-10 mRNAs (p < 0.05). Nuclear protein levels of activator protein-1 were increased in AN (4.4-fold, p < 0.01) and not significantly altered by PDTC (3.0-fold, p = 0.13) or NAC (5. 2-fold, p = 0.18). CONCLUSIONS: The protective effects of PDTC in AN are not associated with a local reduction in TNF-alpha and MCP-1 gene expression. The latter may be due to continued transactivation by activator protein-1. These data also suggest that IL-10 and TGF-beta1 mRNA expressions are PDTC dependent and have a role in mediating tubulointerstitial injury.     

Inhibition of interleukin-1beta-induced COX-2 and EP3 gene expression by sodium salicylate enhances pancreatic islet beta-cell function

Previous work has suggested that functional interrelationships may exist between inhibition of insulin secretion by interleukin (IL)-1beta and the endogenous synthesis of prostaglandin E(2) (PGE(2)) in the pancreatic islet. These studies were performed to ascertain the relative abundance of E prostaglandin (EP) receptor mRNAs in tissues that are major targets, or major degradative sites, of insulin; to identify which EP receptor type mediates PGE(2) inhibition of insulin secretion in pancreatic islets; and to examine possible sites of action through which sodium salicylate might affect IL-1beta/PGE(2) interactions. Real-time fluorescence-based RT-PCR indicated that EP3 is the most abundant EP receptor type in islets, liver, kidney, and epididymal fat. EP3 mRNA is the least, whereas EP2 mRNA is the most, abundant type in skeletal muscle. Misoprostol, an EP3 agonist, inhibited glucose-induced insulin secretion from islets, an event that was prevented by preincubation with pertussis toxin, by decreasing cAMP. Electromobility shift assays demonstrated that sodium salicylate inhibits IL-1beta-induced nuclear factor-kappaB (NF-kappaB) activation. Sodium salicylate also prevented IL-1beta from inducing EP3 and cyclooxygenase (COX)-2 gene expression in islets and thereby prevented IL-1beta from inhibiting glucose-induced insulin secretion. These findings indicate that the sites of action through which sodium salicylate inhibits these negative effects of IL-1beta on beta-cell function include activation of NF-kappaB as well as generation of PGE(2) by COX-2.     

Acute lung injury after hepatic cryoablation: correlation with NF-kappa B activation and cytokine production.

BACKGROUND: Previous clinical reports have documented multisystem organ injury after hepatic cryoablation. We hypothesized that hepatic cryosurgery, but not partial hepatectomy, induces a systemic inflammatory response characterized by distant organ injury and overproduction of nuclear factor kappa B (NF-kappa B)-dependent, proinflammatory cytokines. METHODS: In this study, rats underwent either cryoablation of 35% of liver parenchyma or a similar resection of left hepatic tissue. Serum tumor necrosis factor-alpha and macrophage inflammatory protein-2 levels and NF-kappa B activation were assessed by electrophoretic mobility shift assay at 30 minutes 1, 2, 6, and 24 hours after either procedure. RESULTS: Cryoablation of 35% of liver (n = 22 rats) resulted in lung injury and a 45% mortality rate within 24 hours of surgery, whereas 7% treated with 35% hepatectomy (n = 15 rats) died during the 24 hours after surgery (P < .05, cryoablation vs hepatectomy). Serum tumor necrosis factor-alpha and macrophage inflammatory protein-2 levels were markedly increased in rats (n = 10 rats) 1 hour after hepatic cryoablation compared with rats that underwent partial hepatectomy (P < .005). We evaluated NF-kappa B activation by electrophoretic mobility shift assay in nuclear extracts of liver and lung after cryosurgery and found that NF-kappa B activation was strikingly increased in the liver but not the lung at 30 minutes and in both organs 1 hour after cryosurgery, and returned to baseline in both organs by 2 hours. In rats undergoing 35% hepatectomy, no increase in NF-kappa B activation was detected in nuclear extracts of either liver or lung at any time point. CONCLUSIONS: These data show that hepatic cryosurgery results in systemic inflammation with activation of NF-kappa B and increased production of NF-kappa B-dependent cytokines. Our data suggest that lung injury and death in this animal model is mediated by an exaggerated inflammatory response to cryosurgery.