Effect Of Pyrrolidine Dithiocarbamate Research Articles

Therapeutic effects of pyrrolidine dithiocarbamate on acute lung injury in rabbits

BackgroundAcute lung injury (ALI) and acute respiratory distress syndrome (ARDS) is an early characteristic of multiple organ dysfunction, responsible for high mortality and poor prognosis in patients. The present study aims to evaluate therapeutic effects and mechanisms of pyrrolidine dithiocarbamate (PDTC) on ALI.MethodsAlveolar-arterial oxygen difference, lung tissue edema and compromise, NF-κB activation in polymorphonuclear neutrophil (PMN), and systemic levels of tumor necrosis factor-alpha (TNFa) and intercellular adhesion molecule-1 (ICAM-1) in rabbits induced by the intravenous administration of lipopolysaccharide (LPS) and treated with PDTC. Production of TNFa and IL-8, activation of Cathepsin G, and PMNs adhesion were also measured.ResultsThe intravenous administration of PDTC had partial therapeutic effects on endotoxemia-induced lung tissue edema and damage, neutrophil influx to the lung, alveolar-capillary barrier dysfunction, and high systemic levels of TNFa and ICAM-1 as well as over-activation of NF-κB. PDTC could directly and partially inhibit LPS-induced TNFa hyper-production and over-activities of Cathepsin G. Such inhibitory effects of PDTC were related to the various stimuli and enhanced through combination with PI3K inhibitor.ConclusionNF-κB signal pathway could be one of targeting molecules and the combination with other signal pathway inhibitors may be an alternative of therapeutic strategies for ALI/ARDS.

Effect of pyrrolidinedithiocarbamate on neural developmental disorder of adult offspring with maternal systemic exposure to Poly(I:C) during pregnancy

To explore the correlation between the elevated expression of cytokines under the induction of Poly(I:C) (polycytidylic acid) in maternal hosts and the abnormal behaviors of adult offsprings and understand the intervening effects of nuclear factor NF-κB inhibitor pyrrolidinedithiocarbamate (PDTC). Poly(I:C) or saline was administered to model the maternal infection during early pregnancy in rats. And the expression of cytokines was blocked with PDTC. The maternal levels of tumor necrosis factor alpha and interleukin-10 were determined by ELISA (enzyme-linked immunosorbent assay). The adult offsprings on different treatments were then compared with regards to prepulse inhibition (PPI), passive avoidance and active avoidance. After the administration of Poly(I:C), there was an elevated levels of serum cytokines as shown by the markedly increased serum levels of IL-10 and TNF-α. The serum levels of IL-10 and TNF-α in the model group were significantly higher than those in the control group [(18.26 ± 1.52) pg/ml, (119.64 ± 16.42) pg/ml vs. (0.16 ± 0.13) pg/ml and (11.21 ± 1.81) pg/ml]. The elevation was partly blocked by PDTC. The serum levels of IL-10 and TNF-α in the intervention group [(12.64 ± 2.04) pg/ml and (30.34 ± 2.19) pg/ml respectively] were lower than those in the model group, but still higher than those in the control group. The psychotic-like phenotypes including defects in PPI, passive avoidance and active avoidance were observed in Poly(I:C)-treated offsprings. Such an effect was blunted by the PDTC intervention. The PPI results demonstrated that the PP₂ and PP₈ difference between rats in 3 groups were statistically significant, with a lower PPI value in the model group than in the intervention group, in the intervention group than in the control group and much lower in the model group than in the control group. PP4 was lower in the model group than that in the intervention group, and also lower in the model group than in the control group. There was no significant difference between the control group and the intervention group. The passive avoidance results indicated that T1 was higher in the model group than in the control and intervention groups and there was no statistical difference between the control and intervention groups. T2 was lower in the model group than in the control and intervention groups and there was no statistical difference between the control and intervention groups. And the active avoidance test results showed that total conditioned reflex times of the control group was higher than those of the intervention and model groups. No statistical difference was found between the intervention and model groups. Total reflex rate of the control group was higher than that of the intervention and model groups. No statistical difference was found between the intervention and model groups. PDTC can interfere with neural developmental disorder of adult offsprings through blunting the cytokine-mediated maternal immune response.

Divergent roles of NF-κB and Egr-1 in flow-dependent restenosis after angioplasty and stenting

ObjectiveRestenosis after both angioplasty and stenting is flow dependent. The effects of flow are preventable with the antioxidant pyrrolidine dithiocarbamate (PDTC) after angioplasty but not after stenting. We examined to what extent these observations could be explained by the effect of PDTC on NF-κB and Egr-1, two transcription factors which are both flow- and redox-sensitive. MethodsIn a flow-modified rabbit carotid model of angioplasty and stenting, we assessed the effects of altered flow, injury and PDTC on expression of Egr-1 and nuclear binding activity of NF-κB. We also examined the effects of local delivery of decoy oligodeoxynucleotides (ODN) specific for NF-κB and Egr-1 on morphology at 28 days in normal and low flow. ResultsThe activity of both transcription factors was enhanced by injury (stent>balloon alone) and was further augmented by low flow. PDTC markedly attenuated the activity of NF-κB but not Egr-1. Specific decoy ODN for Egr-1 attenuated intima formation in both stented and balloon injured vessels in both normal and low flow but had no effect on remodelling. In contrast while NF-κB decoy ODN caused a modest but significant reduction in intima formation, there was a striking effect on remodelling in low flow vessels only. ConclusionsWe conclude that Egr-1 plays a pivotal role in intima formation under all flow conditions and that NF-κB plays a key role in flow-sensitive remodelling after angioplasty and that NF-κB inhibition likely accounts for a significant part of the morphological effects of PDTC after vessel injury.

Fetal bovine serum requirement for pyrrolidine dithiocarbamate-induced apoptotic cell death of MCF-7 breast tumor cells

Pyrrolidine dithiocarbamate (PDTC) can form a complex with metal ions and then act as a proteasome inhibitor, which leads to tumor cell apoptosis, and could therefore be developed as an anticancer agent. In our efforts to find factors that induce PDTC-mediated apoptosis of tumor cells, the effect of serum concentration on the apoptotic activity of PDTC was investigated. PDTC could not induce MCF-7 breast tumor cell death in serum-free media but significantly induced cell death in a dose-dependent manner at concentrations of ≥ 25 μM in media containing 10% fetal bovine serum. PDTC-mediated cell death was also dependent on serum concentration. PDTC-mediated cell death occurred through apoptosis. Similar to that in normal FBS, PDTC-mediated apoptotic cell death was also induced in media containing dialyzed FBS, indicating that PDTC-mediated apoptosis does not require metal ions or salts, but rather proteins in fetal bovine serum. In addition, differential apoptotic effects of PDTC were not observed with inhibitors of NF-κB activation such as N-acetylcysteine (NAC), Fenofibrate and carbobenzoxyl- l-leucyl- l-leucyl- l-leucinal (MG132) or with the metal-binding agent, 5-chloro-7-iodo-8-hydroxyquinoline (Clioquinol). These results indicate that serum is required for PDTC-mediated apoptosis and that zinc-binding compounds such as PDTC, N,N,N′ ,N′-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) and Clioquinol may each have their own mechanisms by which they induce tumor cell death, even though they are all classified as zinc-binding compounds.

Effect of inhibitory nuclear factor kappa B on apoptosis of prostate cancer cell line PC-3M inducted by TRAIL

Objective To investigate the suppressive effect of pyrrolidine dithiocarbamate on nuclear factor kappa B and to evaluate the effect of enhancement of PDTC on the apoptosis of androgen-independent prostate cancer cell line PC-3M when tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is used. Methods PC-3M cells were divided to different groups according to the treatment with TRAIL (25,50,100 μg/L) or PDTC (25,50,100 μmol/L) or both of them [25/25,25/50,25/100,50/ 25,50/50,50/100 PDTC( μmol/L) ,TRAIL( μg/L) ]. The nuclear translocation of nuclear factor kappa B was evaluated by cell immunohistochemical method and electrophoretic mobility shift assay ( EMSA). The analys of apoptosis was carried out by MTT test and flow cytometry. Results EMSA and cell immunohistochemical analysis showed that the translocation of nuclear factor kappa B can be greatly activated when PC3M cells were treated with TRAIL. The pretreatment of PDTC can block the nuclear translocation and eliminate the protection to cancer cells in apoptosis. In the meantime, as a stong suppressor of nuclear factor kappa B, PDTC is less toxic. The killing effect of TRAIL + PDTC group is obviously more powerful than TRAIL-single group (P <0. 01) . Conclusion The effect of TRAIL will be remarkably neutralized by the activation of nuclear factor kappa B when it deal with androgen-independent prostate cancer cell. On the other hand,TRAIL can significantly and efficiently induce the apoptosis of PC-3M cells when PDTC is pretreated to inhibit the activation of nuclear factor kappa B. Key words: Prostate neoplasm; Carcinoma; Tumor necrosis factor; Nuclear factor kappa B

Protective effect of pyrrolidine dithiocarbamate on kidney tissue in streptozotocin-induced diabetic rats

Objective: In this study, we investigated protective effects of pyrrolidine dithiocarbamate (PDTC), which is an antioxidant and nuclear factor kappa B (NF-κB) inhibitor, on nephropathy in diabetic rat model. Materials and methods: Twenty-eight Sprague-Dawley rats were allocated into 3 groups. Control group (n=8) received no treatment; diabetes group (n=10) received single intraperitoneal (i.p.) injection of streptozotocin (STZ, 65 mg/kg) to induce experimental diabetes; and PDTC group (n=10) received i.p. 100 μL/day PDTC for a total of 10 weeks following diabetes induction with i.p. STZ injection. At the end of the study kidneys were excised from sacrificed rats, and glomerular and tubular changes were examined under light microscopy. Immunohistochemically, NF-κB (p65) and inducible nitric oxide synthase (iNOS) expression were evaluated in the renal cortex. Results: In diabetes group, immunohistochemical NF-κB expression was higher than control and PDTC groups (p<0.05). In PDTC group, NF-κB expression level was very similar to control group, but less than diabetes group (p<0.05). Immunohistochemical iNOS expression was less in control group. In PDTC group, iNOS expression was more intense than control group (p<0.05), but less than that in diabetes group (p<0.05). Conclusion: PDTC has a protective effect on renal injury secondary to diabetes and can be a treatment option for patients with diabetic nephropathy.

Pyrrolidine Dithiocarbamate Activates p38 MAPK and Protects Brain Endothelial Cells From Apoptosis: A Mechanism for the Protective Effect in Stroke?

The antioxidant and inhibitor of nuclear factor kappaB pyrrolidine dithiocarbamate (PDTC) potently reduces infarct size in various experimental stroke models. In addition, it has been shown to have a favourable safety profile in humans. In this study, we further investigated the mechanistic actions of PDTC on cerebral microvascular endothelial cells as main components of the blood-brain barrier. We propose activation of p38 MAPK by PDTC as an additional protective mechanism. C57/BL6 mice were subjected to transient MCAO for 2 h and treated with PDTC (100 mg/kg) or vehicle i.p. before reperfusion. Infarct size was determined after 24 h. Apoptosis was induced in a cerebral microvascular endothelial cell line and the effect of pretreatment with PDTC and its dependency on p38 MAPK activity was assayed. PDTC administered 2 h after MCAO reduced infarct size by 61% (P < 0.05) and reduces the apoptotic death rate in vivo. In vitro, PDTC reduces the apoptotic death rate of bEnd.3 cells. p38 MAPK was activated by PDTC and its inhibition abrogated the protective effect of PDTC. PDTC reduces infarct size after stroke with a reasonable time window and decreases apoptotic cell death in vivo and in vitro. The attenuation of apoptotic cell death in brain microvascular endothelial cells is dependent on p38 MAPK activity.

Pyrrolidine Dithiocarbamate Inhibition of Luteolin‐Induced Cleavage of Bcl‐2 Family Members in Human Leukemia HL‐60 Cells

In our previous study the cleavage of the proapoptotic Bcl‐2 proteins, such as Bad, Bid and Bax to produce their truncated forms, and the cleavage of the antiapoptotic Bcl‐2 proteins, such as Bcl‐XL, into their potent pro‐apoptotic fragments were detected in luteolin‐treated HL‐60 cells. We also explored the modulatory effects and molecular mechanisms of Pyrrolidine dithiocarbamate (PDTC) on the cytotoxicity of luteolin to HL‐60 cells, and PDTC could interfere with luteolin's ability to cleave poly(ADP‐ribose)‐polymerase (PARP) and DNA fragmentation of factor‐45 (DFF‐45). In the current study, we investigated the effects of PDTC on the luteolin‐induced cleavage of Bcl‐2 family members in human leukemia HL‐60 cells. The results indicated that no cleavage product of Bid, Bad, Bax and Bcl‐XL was found when HL‐60 cells were pre‐treated with PDTC before luteolin treatment. Our results demonstrated that PDTC could inhibit luteolin‐induced cleavage of Bcl‐2 family members, and therefore devoted to the inhibition of luteolin‐induced apoptosis.

Histological Study on the Effect of Pyrrolidine Dithiocarbamate on Hepatic and Small Intestinal Injury Induced by Ischemia Reperfusion in Rats

Introduction: Restoration of the blood flow and reintroduction of oxygen after deprivation accelerate tissue injury. The insult of intestinal ischemia reperfusion (I/R) is not necessarily limited to the intestine itself, but involves the severe destruction of the other tissues because of the reperfused oxygenated blood. Many reports indicated that I/R is an important inciting event in the pathogenesis of multiple organ system failure, which is the leading cause of death in critically ill patients. So, the aim of this study was to evaluate the possible protective role of pyrrolidine dithiocarbamate (PDTC) on liver and small intestinal injury following mesenteric ischemia reperfusion. Materials and Methods: The study was performed on forty adult male albino rats weighting 200-250 gm that were divided into three groups. Group I: Control animals which divided into untreated and sham operated (10 animals each). Group II: Intestinal ischemia reperfusion animals, which were underwent one hour ischemia and two hours reperfusion. Group III: Animals received 200 mg/kg PDTC intraperitoneally one hour before intestinal ischemia reperfusion procedure. Parts were taken from the liver and jejunum were processed for histological examination and other jejunal parts for scanning electron microscopic examinations (SEM). Immunohistochemical expression of NF-κB factor in the liver was investigated. Results: A variety of changes were observed in the jejunum ranging from epithelial separation and loss of the brush border to cellular lysis, destruction of villi, cellular infiltrations, hemorrhages and basal glandular ulcerations. The liver showed areas of edema fluid, hemorrhages, mononuclear cellular infiltration and increased expression of NF-κB factor. Conclusion: Treatment with PDTC resulted in improvement in most of the histological changes induced by intestinal ischemia-reperfusion in the jejunum and liver. Therefore, PDTC can be considered as an effective protecting agent during intestinal ischemia reperfusion and can be used clinically in such instances.

Influence of NFκB inhibitors on IL-1β-induced chemokine CXCL8 and -10 expression levels in intestinal epithelial cell lines: glucocorticoid ineffectiveness and paradoxical effect of PDTC

PurposeActivation of intestinal epithelial cell (IEC) nuclear factor κB (NFκB) and the consequent chemokine upregulation are crucial events in inflammatory bowel disease (IBD) pathogenesis. Not much is known about the consequences of NFκB inhibition in terms of chemokine expression in intestinal cells. Therefore, we aimed to evaluate the efficacy of compounds known to disrupt the NFκB pathway on NFκB transcriptional activity and CXCL8 and CXCL10 gene expression in intestinal cell lines.MethodsThe influence of NFκB inhibitors (dexamethasone, pyrrolidine dithiocarbamate (PDTC) and BAY 11-7082) on IL-1β-induced NFκB transcriptional activity was investigated by transient transfection of Caco-2 cells with an NFκB-secreted alkaline phosphatase reporter plasmid. Il-1β stimulated CXCL8 and CXCL10 mRNA and protein expression and was studied in Caco-2 and HT29 cells in the presence and absence of the NFκB inhibitors by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent serologic assay, respectively. To reveal alternative signalling cascades, experiments were also performed in the presence of the p38MAPK inhibitor SB 203580 and the ERK inhibitor PD 98059.ResultsDexamethasone did not downregulate chemokine expression sufficiently, probably due to a lack of glucocorticoid receptors in these cells. While BAY11-7082 inhibited chemokine expression, PDTC led to a paradoxical upregulation of CXCL8 in Caco-2 cells, which could be prevented by inhibition of p38MAPK.ConclusionThese data explain the frequent unresponsiveness of IBD to glucocorticoid treatment and suggest that alternative NFκB inhibition in IECs might be of use in IBD therapy. Drug development based on measuring anti-NFκB activity might be misleading and should therefore also include studies on relevant gene products.

Pyrrolidine dithiocarbamate protects the piriform cortex in the pilocarpine status epilepticus model

Pyrrolidine dithiocarbamate (PDTC) has a dual mechanism of action as an antioxidant and an inhibitor of the transcription factor kappa-beta. Both, production of reactive oxygen species as well as activation of NF-kappaB have been implicated in severe neuronal damage in different sub-regions of the hippocampus as well as in the surrounding cortices. The effect of PDTC on status epilepticus-associated cell loss in the hippocampus and piriform cortex was evaluated in the rat fractionated pilocarpine model. Treatment with 150 mg/kg PDTC before and following status epilepticus significantly increased the mortality rate to 100%. Administration of 50 mg/kg PDTC (low-dose) did not exert major effects on the development of a status epilepticus or the mortality rate. In vehicle-treated rats, status epilepticus caused pronounced neuronal damage in the piriform cortex comprising both pyramidal cells and interneurons. Low-dose PDTC treatment almost completely protected from lesions in the piriform cortex. A significant decrease in neuronal density of the hippocampal hilar formation was identified in vehicle- and PDTC-treated rats following status epilepticus. In conclusion, the NF-kappaB inhibitor and antioxidant PDTC protected the piriform cortex, whereas it did not affect hilar neuronal loss. These data might indicate that the generation of reactive oxygen species and activation of NF-kappaB plays a more central role in seizure-associated neuronal damage in the temporal cortex as compared to the hippocampal hilus. However, future investigations are necessary to exactly analyze the biochemical mechanisms by which PDTC exerted its beneficial effects in the piriform cortex.

Effects of pyrrolidine dithiocarbamate on high-fat diet-induced metabolic and renal alterations in rats

Aims We investigated the effects of the nuclear factor kappa B (NFκB) blocker pyrrolidine dithiocarbamate (PDTC) on high-fat diet (HFD)-induced metabolic and renal alterations in obese and lean Zucker rats (OZR and LZR, respectively). Main methods Rats were fed a HFD resembling the typical “Western” diet or a regular diet (RD) and allowed free access to tap water or tap water containing PDTC (150 mg/kg body weight) for 10 weeks; rats were then sacrificed. Total ROS production rates were measured using electron paramagnetic resonance spectroscopy, and superoxide production was measured with lucigenin assay. Blood, plasma, and urine were analyzed. Semi-quantitative reverse transcriptase-polymerase chain reaction and electrophoretic mobility shift assay were conducted to assess NFκB mRNA levels and DNA binding activities, respectively; immunofluorescence was performed to assess protein levels. Key findings OZR-HFD rats exhibited significantly higher levels of total renal cortical reactive oxygen species production, plasma lipids, insulin, C-reactive protein, blood urea nitrogen, creatinine, and urinary albumin excretion than all other groups ( p < 0.05); these changes were accompanied by a significant decrease in plasma high density lipoprotein levels ( p < 0.05). Gene expression levels of desmin, cytokine and oxidative stress genes were significantly higher in the renal cortical tissues of OZR-HFD; NFκB p65 DNA binding activity was also significantly higher in these animals. PDTC attenuated these changes. Significance Our data suggest that NFκB blockade may prove beneficial in treating the nephropathy often associated with metabolic syndrome.

The effects of PDTC on interleukin-1β-induced nitric oxide production in chondrocytes

In order to find new drugs to inhibit nitric oxide (NO) production, the effects of pyrrolidine dithiocarbamate (PDTC), a nuclear factor-kappa B (NF-kappaB) inhibitor, on recombinant human interleukin-1beta (rhIL-1beta)-induced NO production in chondrocytes were investigated. Rat chondrocytes were isolated and cultured, divided into control, P0, P1, P2, P3 and P4 groups. The chondrocytes in the P0, P1, P2, P3 and P4 groups were treated with different concentrations of PDTC (0, 3, 10, 30, and 50 micromol/L respectively) for 1 h and then incubated with 5 U/mL rhIL-1beta for 24 h. NO assay kit and RT-PCR were used to detect the NO content and the iNOS mRNA expression in the chondrocytes. The expression level of iNOS mRNA in control, P0, P1, P2, P3 and P4 groups was 0.02+/-0.01, 1.24+/-0.13, 1.21+/-0.14, 0.61+/-0.11, 0.40+/-0.09, 0.21+/-0.06, and the relative content of NO was 15.8+/-2.7, 100+/-14.8, 92.6+/-9.3, 68.3+/-14.2, 27.5+/-9.8, 19.8+/-3.6, respectively. In the P0, P1, P2, P3 and P4 groups, the expression of iNOS mRNA and NO production were significantly increased as compared with those in the control group. As compared with the P0 group, the expression of iNOS mRNA and NO content in control group were lower. In the P2, P3 and P4 groups, PDTC could significantly inhibit the expression of iNOS and NO production induced by rhIL-1beta in a concentration-dependent manner. It is suggested that PDTC can inhibit NO production and iNOS mRNA expression induced by IL-1beta, which may provide an alternative method for the treatment of osteoarthritis.

Pyrrolidine dithiocarbamate, a NF-κB inhibitor, upregulates MMP-1 and MMP-13 in IL-1β-stimulated rheumatoid arthritis fibroblast-like synoviocytes

Activated NF-κB plays an important role in the expression of matrix metalloproteinase (MMP)-1 and MMP-13 in rheumatoid arthritis and osteoarthritis. The objective of this study was to determine the effects of the NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC) on the expression of MMPs in IL-1β-stimulated fibroblast-like synoviocytes (FLSs) of rheumatoid arthritis patients. FLSs were treated with IL-1β (10 ng/ml) for 24 h in the presence or absence of PDTC. The level of MMP-1 and MMP-13 increased in response to PDTC in time- and dose-dependent manners in IL-1β-stimulated FLSs; the expressions of IL-6 and vascular endothelial growth factor (VEGF) decreased in a PDTC concentration-dependent manner. However, PDTC-mediated repression of IL-6 and VEGF expression was not observed in TNF-α-stimulated rheumatoid arthritis FLSs. In contrast, other NF-κB inhibitors, such as fenofibrate, N-acetylcysteine and MG132, decreased MMP expression in IL-1β-stimulated FLSs. The stimulatory effect of PDTC on MMP expression was not mimicked by specific inhibitors of the mitogen-activated protein kinase (MAPK) signaling pathway. Treatments with 100 μM PDTC did not inhibit the phosphorylation of p-ERK1/2, p-P38, and p-JNK, or the transnuclear migration of NF-κB through degradation of IκB-α in IL-1β-stimulated FLSs. These results suggest that the increase of MMP expression may occur in a stimuli-specific manner or by an NF-κB independent mechanism. Therefore, therapeutic NF-κB inhibitors should be thoroughly studied before their clinical use in treating rheumatoid arthritis, as undesirable genes may be upregulated through unknown mechanisms, possibly resulting in worse symptoms.

Oral administration of Pyrrolidine Dithiocarbamate (PDTC) inhibits VEGF expression, tumor angiogenesis, and growth of breast cancer in female mice

The progression of breast cancer is associated with oxidative stress. However, the effects of pyrrolidine dithiocarbamate (PDTC), a known antioxidant, on the development of breast cancer are poorly understood. The present study evaluates the effects of PDTC on tumor growth, the expression of vascular endothelial growth factor (VEGF), and angiogenesis of breast cancer in female mice. Eight week old female mice (C57BL/6J) were given PDTC at 100 to 200 mg/kg/day for 3 weeks (n=10). The control mice received regular drinking water only. In the 2nd wk, 5x10^5 E0771 (mouse breast cancer) cells were injected in the pad of the fourth mammary gland of the mice. Tumor size was monitored using dial calipers. At the end of the experiment, the tumors were isolated and measured for tumor size, intratumoral microvessel (IM) density using CD31 immunohistochemistry staining, NFκB activation using EMSA, and VEGF protein levels using ELISA. PDTC treatment caused a significant decrease in tumor weight compared to the control (0.64±0.22 vs. 1.43±0.31 g; n=8; P

Effect of pyrrolidine dithiocarbamate on hepatic vascular stress gene expression during ischemia and reperfusion

Pyrrolidine dithiocarbamate, an antioxidant and a potent inhibitor of nuclear factor-kappa B (NF-κB), is known to have protective effect against ischemia and reperfusion injury. This study examined the cytoprotective mechanism of pyrrolidine dithiocarbamate against the microcirculatory failure caused by hepatic ischemia and reperfusion. Rats were subjected to 60 min of hepatic ischemia followed by 5 h of reperfusion. Pyrrolidine dithiocarbamate (100 mg/kg) or the vehicle was administered intraperitoneally 24 h before ischemia. The level of serum aminotransferases and hepatic lipid peroxides significantly increased, and the glutathione contents fell in the ischemia/reperfusion group. Pyrrolidine dithiocarbamate prevented the increase in the level of serum enzymes and hepatic lipid peroxides, and the decrease in the glutathione contents. The NF-κB DNA-binding activity was inhibited by a pre-treatment with pyrrolidine dithiocarbamate. Ischemia and reperfusion significantly increased the mRNA expression of the endothelin-1 and endothelin ET B receptor , which was prevented by pyrrolidine dithiocarbamate. There were significant increases in the mRNA expressions of inducible nitric oxide synthase, tumor necrosis factor-alpha, and cyclooxygenase-2, in the livers after ischemia and reperfusion. These increases were attenuated by the pyrrolidine dithiocarbamate treatment. In a rat model of hepatic ischemia and reperfusion, our results suggest that the hepatoprotective actions of pyrrolidine dithiocarbamate may be mediated in part through the modulation of imbalanced expression of vascular stress genes.

Involvement of activating transcription factors JNK, NF-κB, and AP-1 in apoptosis induced by pyrrolidine dithiocarbamate/Cu complex

Pyrrolidine dithiocarbamate (PDTC) is a metal chelator. Biologically, slight toxic affects EC 50, 100 ± 5.9 µM are observed when added to cultured HL-60 cells. CuCl 2 at a physiological concentration (1 µM), but not FeCl 2, Pb potentiated the cytotoxic effect of PDTC by 700 fold (EC 50, 0.14 ± 0.02 µM). Furthermore, results indicated that the PDTC/Cu complex induced an apoptotic process, evidenced by apoptotic bodies, DNA ladder and hypodiploidy cells. Additional studies showed that PDTC/Cu complex significantly decreased mitochondrial membrane potential, increased cytochrome c release, and reactive oxygen species production, and depleted reduced non-protein thiols in a time-dependent manner. Following oxidative stress, the PDTC/Cu complex sequentially activated JNK, NF-κB and AP-1 signaling pathways while IκB kinase activity was enhanced. The apoptotic process was eventually induced by caspase 3 activation and PARP degradation. The non-permeable copper-specific chelator-bathocuproine disulfonate (BCPS) and vitamin C were able to inhibit apoptosis and the elevation of intracellular Cu. Based on these findings; we conclude that PDTC/Cu complex-induced apoptosis is mediated by activation of JNK, NF-κB, AP-1 and caspase 3. Due to its high potency, PDTC may be useful as a therapeutic anti-cancer drug.

Protective effects of pyrrolidine dithiocarbamate against airway inflammation in the ovalbumin-induced mouse model

Pyrrolidine dithiocarbamate (PDTC) is known to exert anti-tumor and anti-inflammatory effects. However, the effects of PDTC against airway inflammation and its underlying mechanisms have not been reported. In the present study, we examined the protective effects of PDTC in a murine model of asthma induced by ovalbumin. PDTC reduced the number of infiltrating inflammatory cells in concert with reduced eosinophil peroxidase (EPO) activity in bronchoalveolar lavage fluid. In parallel, PDTC decreased airway hyperresponsiveness in a dose dependent manner. All these effects were correlated with heme oxygenase-1 (HO-1) mRNA and protein induction, and reversed by ZnPP, a HO-1 inhibitor. In addition, PDTC reduced the secretion of Th 2 cytokines such as IL-4 and IL-5, whereas ZnPP blocked the inhibitory effects of PDTC on Th 2 cytokine secretion. These results suggest that PDTC protects against airway inflammation at least in part via HO-1 induction, and that inhibitory action on Th 2 cytokines may be associated with the protective mechanism of PDTC.

Effects of Pyrrolidine Dithiocarbamate on Antioxidant Enzymes in Cardiomyopathy Induced by Adriamycin in Rats

Objective: The clinical usefulness of adriamycin (ADR) is restricted by the frequent induction of dose-dependent chronic cardiomyopathy. Previous studies on ADR cardiotoxicity have reported that the formation of free reactive oxygen radicals might be involved in ADR cardiotoxicity. Pyrrolidine dithiocarbamate (PDTC) is a potent antioxidant in vivo and in vitro. The present study was undertaken to examine the effects of PDTC on antioxidant enzymes in cardiomyopathy induced by ADR in rats. Methods: Thirty-two male Wistar rats were randomly divided into 4 groups: control, ADR, PDTC, and ADR+PDTC. After 30 days, myocardial histopathological and electron microscopic examinations were performed: the myocardial content of superoxide anion and lipid peroxides were examined; the myocardial total antioxygenation capability (T-AOC) and activity of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were examined; myocardial GSH-Px, Mn-SOD and Cu,Zn-SOD gene expressions were examined by RT-PCR analysis, and the myocardial expression of GSH-Px, Mn-SOD and Cu,Zn-SOD proteins was assessed by Western blot analysis. Results: At 30 days, ADR-induced cardiomyopathy was confirmed by structural examination. The changes were prevented by PDTC. Myocardial superoxide anion and lipid peroxides were increased by ADR, and these changes were also inhibited by PDTC. ADR decreased myocardial T-AOC and the activity of GSH-Px and SOD, and these changes were likewise inhibited by PDTC. mRNA and protein expression of GSH-Px and Mn-SOD were depressed by ADR treatment and prevented by PDTC. Cu,Zn-SOD mRNA and protein levels were not significantly changed by ADR or PDTC. Conclusion: PDTC prevented ADR cardiomyopathy in rats by upregulating GSH-Px and SOD activation, which is associated with changes in the expression of GSH-Px and Mn-SOD transcript and protein levels.

Differential effects of pyrrolidine dithiocarbamate on TNF-α-mediated liver injury in two different models of fulminant hepatitis

Pyrrolidine dithiocarbamate (PDTC) is an inhibitor of nuclear factor kappa B (NF-kappaB) activation. The present study aimed to investigate the effects of PDTC on lipopolysaccharide (LPS)-induced liver injury in two different models of fulminant hepatitis. Mice infected with Bacillus Calmette Guerin (BCG) were challenged with LPS (0.2 mg/kg) to induce the model of inflammatory liver injury. Mice were injected with D-galactosamine (GalN, 600 mg/kg) and LPS (20 microg/kg) to induce the model of apoptotic liver injury. In the treatment groups, mice were pre-treated with PDTC (100 mg/kg), initiated 24 h prior to LPS. PDTC pretreatment reduced the infiltration of inflammatory cells, inhibited NF-kappaB activation and the expression of tumor necrosis factor alpha (TNF-alpha), attenuated nitric oxide production, and alleviated hepatic glutathione depletion. Correspondingly, PDTC reduced serum alanine aminotransferase, improved hepatic necrosis, and prolonged the survival in the BCG/LPS model. Conversely, PDTC accelerated death and aggravated liver apoptosis in the GalN/LPS model, although it reduced nitric oxide production, attenuated glutathione depletion, and inhibited the expression of TNF-alpha in liver. PDTC protects mice against BCG/LPS-induced inflammatory liver injury through the repression of NF-kappaB-mediated TNF-alpha release, while it seems to be detrimental in GalN/LPS-induced apoptotic liver damage.