The protective effect of N-acetylcysteine against cyclosporine A-induced hepatotoxicity in rats

Exploring the role of oxidative stress and the effect of N-acetylcysteine in thiopurine-induced liver injury in inflammatory bowel disease: A randomized crossover pilot study

Thiopurine treatment is regularly complicated by drug-induced liver injury. It has been suggested that oxidative stress may play a synergistic role. To assess whether thiopurine-induced liver injury coincides with increased oxidative stress and whether co-administration with N-acetylcysteine is protective, we performed a randomized open label crossover pilot study in inflammatory bowel disease patients with thiopurine-induced increased serum liver tests. The study comprised four stages of 4 weeks. Patients received no additional therapy followed by N-acetylcysteine 1200 mg twice a day, or the other way around, alongside ongoing thiopurine treatment. The third and fourth stages comprised a washout period and thiopurine reintroduction period. Nine patients completed the study, and the addition of N-acetylcysteine decreased myeloperoxidase concentrations (33.6-24.5 pmol/L, p = 0.038). The other biomarkers remained unchanged, including thiopurine metabolites, xanthine oxidase activity, thiopurine S-methyltransferase activity and serum liver enzyme activity tests. Reintroduction of thiopurines led to an increase of F2-isoprostanes (101-157 ng/mmol, p = 0.038), but not of serum liver enzyme activity tests. Results suggests that thiopurines may increase oxidative stress and although the addition of N-acetylcysteine led to a decrease in plasma myeloperoxidase concentrations, it does not protect from thiopurine-induced increase of serum liver tests.

Pomegranate peel extract, N-Acetylcysteine and their combination with Ornipural alleviate Cadmium-induced toxicity in rats

Cadmium is a major environmental pollutant and a highly toxic metal. It was aimed to determine the effects of pomegranate peel extract (PPE), N-acetylcysteine (NAC) alone and along with Ornipural on cadmium-induced toxicity. Forty-six Wistar Albino male rats were divided into 6 groups and the groups were formed into healthy control, Cadmium group (5 mg/kg/day, oral), Cadmium + Pomegranate peel extract (500 mg/kg, oral), Cadmium + N-acetylcysteine (100 mg/kg, oral), Cadmium + Pomegranate peel extract (500 mg/kg, oral) + Ornipural (1 mL/kg, subcutaneous) and Cadmium + N-acetylcysteine (100 mg/kg, oral) + Ornipural (1 mL/kg, subcutaneous). Cadmium accumulated heavily in both liver and kidney tissue. The administration of N-acetylcysteine and pomegranate peel extract alone reduced cadmium levels in both tissues. N-acetylcysteine treatment prevented the increase in ALT and MDA levels by cadmium damage. N-acetylcysteine + Ornipural treatment inhibited the increase in liver 8-OHdG level in the liver. N-acetylcysteine and N-acetylcysteine + Ornipural treatments prevented the reduced serum MMP2 level. N-acetylcysteine and Pomegranate peel extract + Ornipural treatments significantly reduced the increased liver iNOS level in the liver. In conclusion, NAC therapy may be a successful treatment option for cadmium toxicity. However, further research is needed on the effects of PPE and Ornipural combinations for the treatment of cadmium toxicity. In future studies, various doses of these treatment options (with chelators) should be investigated for cadmium toxicity.

Galangin attenuates cadmium-evoked nephrotoxicity: Targeting nucleotide-binding domain-like receptor pyrin domain containing 3 inflammasome, nuclear factor erythroid 2-related factor 2, and nuclear factor kappa B signaling

The kidney is highly vulnerable to cadmium-evoked oxidative injury. Galangin is a natural flavone with reported antioxidant properties. This study investigated the potential modulating activity of galangin against cadmium-induced nephrotoxicity and explored the underlining mechanisms. Western blot analysis, spectrophotometric, ELISA, and histopathological techniques were employed. The results revealed that galangin suppressed tubular injury and improved glomerular function in the cadmium-intoxicated rats as evidenced by downregulation of kidney injury molecule-1, serum creatinine, and blood urea nitrogen. Galangin reduced cadmium-evoked inflammatory response and oxidative stress as indicated by reduced levels of interleukin-1 beta and TNF-α, decreased DNA damage, and improved antioxidant potential of the renal tissues. Mechanistically, galangin suppressed the nucleotide-binding domain-like receptor pyrin domain containing 3 inflammasome and efficiently decreased caspase-1 activity in the cadmium-intoxicated rats. Equally important, it inhibited the cadmium-induced nuclear translocation of nuclear factor kappa B and upregulated nuclear factor erythroid 2-related factor 2 signaling. The results highlight the ability of galangin to attenuate cadmium-evoked nephrotoxicity and support its therapeutic implementation although clinical investigations are warranted.

Upregulation of Nrf2 signaling and suppression of ferroptosis and NF-κB pathway by leonurine attenuate iron overload-induced hepatotoxicity

Hepatotoxicity is a major health concern that associates the iron overload diseases including hemochromatosis, sickle cell anemia, and thalassemia. Induction of ferroptosis, oxidative stress, and inflammation substantially mediates the iron-evoked hepatotoxicity. The current work investigated the potential protective effect of the natural alkaloid leonurine against the iron-induced hepatotoxicity and elucidated the underlining molecular mechanisms. Male Wistar rats were treated with iron only (30 mg/kg every other day over a ten-day period via intraperitoneal injection) or with iron and leonurine (leonurine: 100 mg/kg/day per oral via gastric gavage for 10 days) to establish the iron-overload model. Liver and blood specimens were then collected and subjected to molecular, biochemical, and histopathological investigations. The results revealed the ability of leonuirne to suppress the iron-induced ferroptosis as reflected by modulation of the ferroptotic biomarkers glutathione peroxidase 4, cyclooxygenase-2, liver iron content, lipid hydroperoxides, and the leakage of the liver intracellular enzymes. Leonurine alleviated the iron-induced oxidative damage and inflammatory response in the liver tissues as indicated by decreased levels of DNA oxidation, lipid peroxidation, and the pro-inflammatory cytokines. In the same context, it improved the antioxidant potential of the liver tissues and ameliorated the iorn-induced histopathological abnormalities. Mechanistically, leonurine enhanced nuclear translocation of the antioxidant transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) and increased protein levels of its downstream targets NAD(P)H-quinone oxidoreductase 1 and heme oxygenase-1. Additionally, it suppressed the nuclear translocation of the inflammatory transcription factor nuclear factor kappa B (NF-κB) and downregulated its downstream pro-inflammatory cytokines tumor necrosis factor-alpha and interleukin-1 beta. The study highlights the hepatoprotective activity of leonurine against the iron-evoked hepatotoxicity that is potentially mediated through modulation of Nrf2 and NF-κB signaling.

The protective effect of resveratrol against cyclosporine A-induced oxidative stress and hepatotoxicity

The immunosuppressive agent cyclosporine A (CsA) has hepatotoxic potential. Increased reactive oxygen species (ROS) formation is among the causes leading to hepatotoxicity. This study aimed to investigate the effect of resveratrol (RES) on CsA-induced oxidative stress and hepatotoxicity in rats. Rats were treated with RES (10 mg/kg/day; i.p.) for 14 days. CsA (25 mg/kg/day; s.c.) was given during the last seven days together with RES. Serum alanine aminotransferase and aspartate aminotransferase activities together with hepatic histopathological examinations were performed. ROS, thiobarbituric acid reactive substances (TBARS), advanced oxidation protein products (AOPPs), ferric reducing antioxidant power, and glutathione levels as well as superoxide dismutase, and glutathione peroxidase activities were measured in the liver tissue. RES ameliorated histopathological changes and decreased hepatic ROS, TBARS, and AOPP levels significantly. However, antioxidant parameters did not change in CsA-treated rats. Our results indicate that RES treatment may be effective in decreasing CsA-induced oxidative stress and hepatotoxicity.

Antifibrotic effect of curcumin, N-acetyl cysteine and propolis extract against bisphenol A-induced hepatotoxicity in rats: Prophylaxis versus co-treatment

AIMS

Bisphenol A (BPA) has been shown to induce liver fibrosis in rodents. Therefore, this study examined the protective effect of a triple combination of curcumin (Cur), N-acetyl cysteine (NAC) and propolis (Prp) extract against BPA-induced hepatic fibrosis.

METHODS

100 Wistar male rats were equally assigned into 10 groups; one group was designated as control. 10 rats were gavaged with BPA (50 mg/kg/day) for 8 wk and left un-treated (BPA group). The remaining 80 rats were divided into 8 groups, distributed in 2 models. Protective model: rats were daily co-treated with BPA and Cur (100 mg/kg, p.o) or NAC (150 mg/kg, p.o) or Prp (200 mg/kg, p.o) or their combination for 8 wk. Preventive model: rats were daily treated with Cur or NAC or Prp or their combination for 4 wk before BPA administration and then in the same manner as protective model.

KEY FINDINGS

Current treatment interventions significantly alleviated BPA-induced hepatic damage and fibrosis. They also restored pro-oxidant/antioxidant balance, shifted cytokine balance towards the anti-inflammatory side, decreasing interleukin-1β/interleukin-10 ratio. Moreover, these compounds seem to exert anti-apoptotic effects by increasing the immunoexpression of B-cell lymphoma 2 in hepatocytes and decreasing hepatic caspase-3 content. Finally, they ameliorated extracellular matrix turn over through down-regulation of matrix metalloproteinase-9 and up-regulation of tissue inhibitor of matrix metalloproteinase-2 genetic expression.

SIGNIFICANCE

Current treatments guarded against BPA-induced hepatic fibrosis due to their antioxidant, anti-inflammatory and anti-apoptotic properties, decreasing extracellular matrix turnover. Interestingly, the triple therapy provided hepatoprotection superior to monotherapy. Besides, prophylactic and concurrent treatments seem to be more effective than concurrent treatments.

Nontoxic concentration of ochratoxin A decreases the dosage of cyclosporine A to induce chronic nephropathy model via autophagy mediated by toll-like receptor 4

Cyclosporine A (CsA) extracted from the products of fungal fermentation is used to develop a chronic nephropathy model. However, it has numerous side effects. Ochratoxin A (OTA) is a mycotoxin that induces renal injury. We developed a chronic nephropathy model to lessen the side effects of CsA by administration of nontoxic dosage of OTA, and investigated the underlying mechanism. C57BL/10 wild-type mice, toll-like receptor 4 (TLR4)-/- mice, and HK-2 cells were used in this study. The nontoxic dosage (0.25 mg/kg, qod) of OTA could significantly decrease the dosage of CsA from 30 to 20 mg/kg per day, and combination of them induced chronic nephropathy model and alleviated the side effects of onefold CsA in vivo, including cardiotoxicity, hepatotoxicity, and immunosuppression. The nontoxic concentration (0.5 μg/ml) of OTA could significantly decrease the concentration of CsA from 10 to 6 μg/ml that induced cytotoxicity, oxidative stress, and nephrotoxicity in vitro. Nontoxic concentration of OTA and low dosage of CsA activated TLR4 and autophagy. These toxic effects induced by OTA and CsA could be reversed by knockdown of TLR4 and autophagy inhibitor 3-methyladenine in vitro. Furthermore, the renal injury and autophagy induced by OTA and CsA could be attenuated in TLR4-/- mice. It suggested that a chronic nephropathy model had been successfully developed by administration of nontoxic concentration of OTA and low dosage of CsA via TLR4-mediated autophagy. The side effects of current model were significantly lesser than those of the previous model induced by onefold CsA. It provided a new tool for exploring the pathogenesis and treatment of chronic kidney disease.

Cyclosporin A activates human hepatocellular carcinoma (HepG2 cells) proliferation: implication of EGFR-mediated ERK1/2 signaling pathway

One of the most common causes of cancer mortality worldwide is hepatocellular carcinoma (HCC). Extracellular signal-regulated kinase (ERK1/2) pathway has been shown to play an important role in the development and progression of HCC. Here, we demonstrate that the immunosuppressive agent cyclosporin A (CsA) has the ability to increase the cellular growth in HCC (HepG2 cells) via activation of ERK1/2 signaling cascade. It was found that ERK1/2 phosphorylation induced by CsA was highly reduced in the presence of the reactive oxygen species (ROS) scavenger polyethylene glycol-superoxide dismutase (PEG-SOD). Furthermore, it was observed that inhibition of metalloproteinase activity using TAPI-2 prevents ERK1/2 activation by CsA. Moreover, a disintegrin and metalloproteinase domain 17 (ADAM-17) activity was found to be critical for ERK phosphorylation by CsA. In addition, CsA-induced ERK phosphorylation was highly reduced in the presence of either neutralizing anti-heparin-binding-epidermal growth factor (HB-EGF) antibody or UO126 (MEK inhibitor). By using the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor AG1478, it was found that EGFR is critical for ERK phosphorylation induced by CsA. Furthermore, CsA-induced cell proliferation was strongly reduced in the presence of either PEG-SOD or TAPI-2 or neutralizing anti-ADAM17 antibody or neutralizing anti-HB-EGF antibody or AG1478 or UO126. Collectively, these data demonstrate that CsA has the ability to activate ERK1/2 signaling cascade that could be translated into an increase in HepG2 cell proliferation. Furthermore, these data support the role of ROS, ADAM-17, and EGFR in ERK1/2 signaling activation and subsequent cell proliferation induced by CsA in HepG2 cells.

The Comparison of Parameters of Oxidative Stress in Native Rat Livers Between Different Immunosuppressive Regimens

Background

It is thought that immunosuppressive treatment, besides anti-rejection properties, leads to pathological changes within the organ due to activation of mechanisms associated with oxidative stress. The aim of this study was to examine the parameters of oxidative stress in the livers of rats treated with the most commonly used transplant recipient drug regimens.

Material/Methods

The rat livers were obtained from archival material obtained from the previously performed experiment. Malondialdehyde (MDA), reduced glutathione (GSH) concentrations, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities were analyzed.

Results

Only the group treated with tacrolimus (T), mycophenolate mofetil (M), and prednisone (P), the TMP group, showed a slight increase in lipid peroxide concentration compared to the control group, though the difference was not statistically significant. Comparison of lipid peroxide concentration between the other treatment combinations and the control group showed a significant decrease. Additionally, a difference in lipid peroxide concentrations in the livers was observed between the cyclosporine A (C) group and tacrolimus (T) group. Alterations of other oxidative stress parameters were also observed in different regimens.

Conclusions

Long-lasting immunosuppressive treatment does indeed affect redox status; however, the antioxidant defenses of the liver against the effects of excess hydrogen peroxide are efficient, so the superoxide dismutase/glutathione peroxidase (SOD/GPx) and superoxide dismutase/catalase (SOD/CAT) ratios were not significant.

The Pharmacokinetic Prediction of Cyclosporin A after Coadministration with Wuzhi Capsule

We aim to describe the influence of principal ingredients of Wuzhi capsule, schisandrin A (SIA) and schisantherin A (STA), on the pharmacokinetics of cyclosporin A (CsA) and to quantify the herb-drug interactions (HDIs) between SIA, STA, and CsA. CsA is a first-line immunosuppressant for anti-rejection therapy after solid organ transplantation, while narrow therapeutic window associated with strong hepatotoxicity largely limited its use. Wuzhi capsule, a liver-protective drug, was approved for coadministration with CsA to reduce the hepatotoxicity. There are few studies exploring HDIs of CsA when coadministered with Wuzhi capsule. The essential adjusted physicochemical data and pharmacokinetic parameters of SIA, STA, and CsA were collected. Then physiologically based pharmacokinetic (PBPK) models of SIA, STA, and CsA were built and verified in healthy subjects using Simcyp respectively. The refined PBPK models were used to estimate potential HDIs between CsA and SIA, STA. The simulated plasma concentration-time curves of CsA, SIA, and STA were in good accordance with the observed profiles respectively. CsA pharmacokinetics were improved after coadministration. After a single dose and multiple doses, the area under the plasma concentration-time curve (AUC) of CsA was increased by 47% and 226% when coadministered with STA, respectively, and by 8% and 36% when coadministered with SIA, respectively. PBPK models sufficiently described the pharmacokinetics of CsA, SIA, and STA. Compared with SIA, STA inhibited CsA metabolism to a greater extent. Our result revealed the dose of CsA can be reduced to maintain similar profile when used concomitantly with Wuzhi capsule.

Amelioration of fenitrothion induced oxidative DNA damage and inactivation of caspase-3 in the brain and spleen tissues of male rats by N-acetylcysteine

N-acetylcysteine (NAC) has largely been used as an effective chemo- protective agent owing to their beneficial effect in restoring several physiological parameters and relieving oxidative stress. Interestingly, it has been suggested that NAC mechanisms of action extend beyond being a precursor to the antioxidant glutathione and that they may involve several neurotropic and inflammatory pathways. Exposure to fenitrothion, an organophosphorus insecticide, promotes oxidative stress and induces several deleterious changes in the immune response and various tissues including cerebrum and spleen. The main objective of our study was to investigate ameliorative efficacy of N-acetylcysteine for immunological and neurological alterations and oxidative DNA damage induced by fenitrothion toxicity in cerebrum and spleen tissues of male rats. Our results revealed that oral exposure to fenitrothion for 30 days caused a reduction in the erythrocyte count in addition to leukocytosis, lymphocytosis, and neutrophilia. Also, this route of administration increased the serum levels of LDH, TNF-α, and IL-2 with reduction in serum immunoglobulins (IgG & IgM) concentrations. Furthermore, a significant downregulation in the antioxidant markers (GSH & SOD) with an elevation of free radical (MDA) levels were noticed. Regarding the brain, fenitrothion administration inhibited AchE activity and increased brain GABA, serotonin and dopamine levels. Moreover, it induced an elevation in oxidative DNA damage indicated by 8-hydroxy 2-deoxyguanosine (8OH2dG) and mRNA expression of pro-apoptotic genes, including Bax, and p53, but Bcl-2 expression was reduced. N-acetylcysteine co-treatment restored the normal physiological tone in most of these parameters. Immunostaining for GFAP and Caspase-3 markers in the brain and spleen tissues were increased respectively. In conclusion, N-acetylcysteine supplementation has an ameliorative effect against immunotoxic, neurotoxic and oxidative DNA damage induced by fenitrothion exposure.

Effect of long-term immunosuppressive therapy on native rat liver morphology and hepatocyte- apoptosis

A negative result of therapy based on immunosuppressive drugs is its leading to pathological alterations in the organ, including liver. Use of immunosuppressive medication may also lead to organized and genetically controlled cell death - apoptosis. The aim of this study was to examine histopathological changes in the livers of rats treated with immunosuppressive drugs, and also to determine the effects of different groups of immunosuppressive drugs on apoptosis activity in the hepatocytes of rat livers. The study was conducted on archival material obtained from Department of Nephrology, Transplantology and Internal Medicine of the Independent Public Clinical Hospital No. 2 at the Pomeranian Medical University in Szczecin, Poland. Statistical comparison of the treatment groups showed that all groups with rapamycin (sirolimus)-based regimens: Tacrolimus, Rapamycin, Glucocorticosteroid (TRG); Cyclosporine, Rapamycin, Glucocorticosteroid (CRG); Mycophenolate, Rapamycin, Glucocorticosteroid (MRG) and additionally Cyclosporine, Mycophenolate, Glucocorticosteroid (CMG) exhibited significantly more pronounced apoptosis than the control group, with p < 0.01, p < 0.05, p < 0.01 and p < 0.01, respectively. Furthermore, in the TRG group, over 90% of apoptotic hepatocytes were seen in the examined classic lobules. Additionally, every liver from treatment group was pathologically altered, including dilated sinusoids, pyknotic nuclei, swollen walls of the vessels. Long-lasting immunosuppressive treatment affects the liver both in terms of histological changes within the structure of the liver and in terms of the percentage of apoptotic hepatocytes. The following study seems to be very innovating due to the duration of the experiment and used drugs-protocols, since they reflect human treatment.

Quillaja saponaria bark saponin protects Wistar rats against ferrous sulphate-induced oxidative and inflammatory liver damage

CONTEXT

Saponins from different sources are historically reported in Chinese medicine to possess many beneficial effects. However, insufficient experimental data are available regarding the hepatoprotective potential of Quillaja bark saponin.

OBJECTIVE

The protective effect of Quillaja saponaria Molina (Quillajaceae) bark triterpenoid saponin against iron-induced hepatotoxicity is compared to the standard N-acetylcysteine in adult male Wistar rats.

MATERIALS AND METHODS

Animals were divided into (six) groups, namely a normal control, an N-acetylcysteine control (300 mg/kg/day, p.o., 10 days), a saponin control (100 mg/kg/day, p.o., for 10 days), a hepatotoxicity control (two doses of ferrous sulphate, 30 mg/kg/day each, i.p., on 9th and 10th day), an N-acetylcysteine plus ferrous sulphate (standard treatment) and a saponin plus ferrous sulphate (test treatment) group. Hepatocyte integrity loss markers (serum ALT, AST, ALP, GGT and LDH), oxidative stress markers (hepatic MDA, GSH and NOx), dyslipidaemic markers (serum TC and TG) and hepatocyte functioning markers (serum bilirubin and albumin) were assessed.

RESULTS

Quillaja bark saponin decreased iron-induced elevation of ALT (reaching 57% of hepatotoxicity control), AST (66%), ALP (76%), GGT (60%), LDH (54%), MDA (65%), NOx (77%), TC (70%), TG (54%), and total (54%), direct (54%) and indirect (54%) bilirubin, coupled with increased GSH (219%) and albumin (159%) levels. Histopathological study strongly supported biochemical estimations, while immunohistochemical study showed marked effect on eNOS and iNOS expression.

CONCLUSIONS

Quillaja bark saponin has a good hepatoprotective effect. Amelioration of oxidative stress and suppression of NOS expression, with resultant maintenance of hepatocyte integrity and functioning, may explain this beneficial effect.

Oxidative Stress and Liver Morphology in Experimental Cyclosporine A-Induced Hepatotoxicity

Cyclosporine A is an immunosuppressive drug used after organ's transplantation. The adverse effects on such organs as kidney or liver may limit its use. Oxidative stress is proposed as one of the mechanisms of organs injury. The study was designed to elucidate CsA-induced changes in liver function, morphology, oxidative stress parameters, and mitochondria in rat's hepatocytes. Male Wistar rats were used: group A (control) receiving physiological saline, group B cyclosporine A in a dose of 15 mg/kg/day subcutaneously, and group C the CsA-vehicle (olive oil). On the 28th day rats were anesthetized. The following biochemical changes were observed in CsA-treated animals: increased levels of ALT, AST, and bilirubin in the serum, statistically significant changes in oxidative stress parameters, and lipid peroxidation products in the liver supernatants: MDA+4HAE, GSH, GSSG, caspase 3 activity, and ADP/ATP, NAD(+)/NADH, and NADP(+)/NADPH ratios. Microscopy of the liver revealed congestion, sinusoidal dilatation, and focal hepatocytes necrosis with mononuclear cell infiltration. Electron microscope revealed marked mitochondrial damage. Biochemical studies indicated that CsA treatment impairs liver function and triggers oxidative stress and redox imbalance in rats hepatocytes. Changes of oxidative stress markers parallel with mitochondrial damage suggest that these mechanisms play a crucial role in the course of CsA hepatotoxicity.

Role of endoplasmic reticulum stress in drug-induced toxicity

Drug‐induced toxicity is a key issue for public health because some side effects can be severe and life‐threatening. These adverse effects can also be a major concern for the pharmaceutical companies since significant toxicity can lead to the interruption of clinical trials, or the withdrawal of the incriminated drugs from the market. Recent studies suggested that endoplasmic reticulum (ER) stress could be an important event involved in drug liability, in addition to other key mechanisms such as mitochondrial dysfunction and oxidative stress. Indeed, drug‐induced ER stress could lead to several deleterious effects within cells and tissues including accumulation of lipids, cell death, cytolysis, and inflammation. After recalling important information regarding drug‐induced adverse reactions and ER stress in diverse pathophysiological situations, this review summarizes the main data pertaining to drug‐induced ER stress and its potential involvement in different adverse effects. Drugs presented in this review are for instance acetaminophen (APAP), arsenic trioxide and other anticancer drugs, diclofenac, and different antiretroviral compounds. We also included data on tunicamycin (an antibiotic not used in human medicine because of its toxicity) and thapsigargin (a toxic compound of the Mediterranean plant Thapsia garganica) since both molecules are commonly used as prototypical toxins to induce ER stress in cellular and animal models.

Oxidative Stress and Inflammation in Hepatic Diseases: Therapeutic Possibilities of N-Acetylcysteine

Liver disease is highly prevalent in the world. Oxidative stress (OS) and inflammation are the most important pathogenetic events in liver diseases, regardless the different etiology and natural course. N-acetyl-l-cysteine (the active form) (NAC) is being studied in diseases characterized by increased OS or decreased glutathione (GSH) level. NAC acts mainly on the supply of cysteine for GSH synthesis. The objective of this review is to examine experimental and clinical studies that evaluate the antioxidant and anti-inflammatory roles of NAC in attenuating markers of inflammation and OS in hepatic damage. The results related to the supplementation of NAC in any form of administration and type of study are satisfactory in 85.5% (n = 59) of the cases evaluated (n = 69, 100%). Within this percentage, the dosage of NAC utilized in studies in vivo varied from 0.204 up to 2 g/kg/day. A standard experimental design of protection and treatment as well as the choice of the route of administration, with a broader evaluation of OS and inflammation markers in the serum or other biological matrixes, in animal models, are necessary. Clinical studies are urgently required, to have a clear view, so that, the professionals can be sure about the effectiveness and safety of NAC prescription.

Molecular mechanisms of the protective role of wheat germ oil against cyclosporin A-induced hepatotoxicity in rats

CONTEXT

Cyclosporin A (CsA) is one of the most important immunosuppressive agents. However, its clinical use is strongly limited by several side effects including hepatotoxicity which remains a major clinical problem. Involvement of reactive oxygen species (ROS) in CsA-induced hepatotoxicity has been reported.

OBJECTIVE

This study investigates the potential protective role of wheat germ oil (WGO) as an antioxidant against CsA-induced hepatotoxicity.

MATERIALS AND METHODS

Twenty-four male Wistar albino rats (six animals in each group) received castor oil, the vehicle of CsA i.p. (control) or either CsA (25 mg/kg/d i.p.), WGO (900 mg/kg/d by oral gavage), or CsA in combination with WGO daily for 21 d.

RESULTS

CsA administration significantly increased serum levels of the liver enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST). In addition, an increase in lipid peroxidation, inducible NO-synthase (iNOS), and NF-κB expression were observed in hepatic tissues of CsA-alone-treated rats. Furthermore, significant reduction in the hepatic content of reduced glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) was also observed in CsA-alone-treated animals. Moreover, histopathological changes occurred in CsA-alone-treated rats. Concomitant administration of WGO along with CsA improved all these parameters. Most interestingly, the immunosuppressive effect of CsA was not affected by WGO.

CONCLUSION

The present study suggests that concomitant use of WGO might be useful in reducing liver toxicity induced by CsA via inhibition of ROS, iNOS, and NF-κB expression.

Protective effect of N-acetylcysteine against ischemia/reperfusion injury in rat urinary bladders

Ischemia/reperfusion (I/R) injury represents an important cause of bladder contractile dysfunction. One of the major causes leading to this dysfunction is thought to be reactive oxygen species formation. In this study, we investigated the potential benefit of N-acetylcysteine (NAC), a potent antioxidant that neutralizes free radicals, in a rat model of urinary bladder injury. NAC treatment rescues the reduction of contractile response to I/R injury in a dose-dependent manner. In addition, all levels of reactive oxygen species, lipid peroxidation, and NADPH-stimulated superoxide production in the I/R operation+NAC (I/R+NAC) group also decreased compared with a marked increase in the I/R operation+saline (I/R+S) group. Moreover, an in situ fluorohistological approach also showed that NAC reduces the generation of intracellular superoxides enlarged by I/R injury. Together, our findings suggest that NAC has a protective effect against the I/R-induced bladder contractile dysfunction via radical scavenging property.

N-Acetylcysteine prevents doxorubucine-induced cardiotoxicity in rats

This study is designed to observe the effects of N-acetylcysteine (NAC) on doxorubucine-induced cardiac toxicity in rats both histologically and biochemically. Totally 32 rats divided equally into four groups were studied. The first group received only 200 mg/kg NAC intraperitoneal (i.p.) once every 24 h for 5 days (group 1); the second group received 20 mg/kg doxorubucine (DOX) i.p. single dose plus NAC 200 mg/kg i.p. once every 24 h for 5 days (group 2); the third group received DOX 20 mg/kg DOX i.p. single dose (group 3) and the fourth group, which is also the control group, received saline (group 4). Following 24 h of the final dose, blood samples were drawn from a portal vein and heart tissue were obtained. Tissue thiobarbituric acid reactive substance (TBARS) and nitric oxide (NO) levels were highest in the DOX group. In the DOX-treated rats, serum TBARS, NO, aspartate transaminase, lactate dehydrogenase and creatine kinase levels were highest when compared with other groups. Except for serum superoxide dismutase levels, all other parameters differed significantly between the DOX plus NAC group and the DOX group. In the DOX plus NAC group, general architecture was preserved better than the DOX group and myofibril loss was minimal compared with the DOX group. NAC demonstrated, both biochemically and histologically, to be effective in the prevention of DOX-induced cardiotoxicity in rat models. Evaluation of NAC’s effect on DOX toxicity warrants further clinical trials on cancer patients.

Cyclosporine A: impact on mitochondrial function in endothelial cells

INTRODUCTION

Although cyclosporine A (CSA) is considered to be an efficient immunosuppressive compound in transplantation, vascular side effects like arterial hypertension, neurologic complications and other adverse reactions occur. Interference of CSA with mitochondrial function may be responsible for these side effects.

METHODS

We evaluated the effect of CSA on mitochondrial and glycolytic function by measuring fatty acid oxidation (FAO), activities of respiratory chain complexes (RC) and citratesynthase (CS), lactate/pyruvate-ratios, energy-rich phosphates as well as activities of some glycolytic enzymes in human umbilical vein endothelial cells.

RESULTS

After 48 h of CSA incubation, global FAO, RC-complexes 1 + 3; 4 and 5 as well as CS were compromised while energy charges were not reduced. Lactate/pyruvate-ratios increased; cellular lactate dehydrogenase (LDH)-, hexokinase- and phosphofructokinase-activities were not impaired by CSA. Moderate cellular toxicity, assessed by LDH leakage, appeared only at the highest CSA concentration.

CONCLUSION

Part of CSA toxicity may arise from alterations in mitochondrial function as judged by impaired FAO and respiratory chain enzymes. To some extent, energy balance seems to be maintained by cytosolic energy production. Although only demonstrated for endothelial cells, it is conceivable that such effects will alter energy metabolism of different organs with high oxidative energy demands.

Hepatoprotective effects of salidroside on fulminant hepatic failure induced by d-galactosamine and lipopolysaccharide in mice

Objectives

The aim was to investigate the protective effect of salidroside isolated from Rhodiola sachalinensis A. Bor. (Crassulaceae) on d-galactosamine/lipopolysaccharide-induced fulminant hepatic failure.

Methods

Hepatotoxicity was induced by an intraperitoneal injection of d-galactosamine (700 mg/kg) and lipopolysaccharide (10 μg/kg); salidroside (20, 50 and 100 mg/kg) was administered intraperitoneally 1 h before induction of hepatoxicity. Liver injury was assessed biochemically and histologically.

Key findings

Salidroside attenuated the induced acute increase in serum aspartate aminotransferase and alanine aminotransferase activities, and levels of tumour necrosis factor-alpha levels and serum nitric oxide. It restored depleted hepatic glutathione, superoxide dismutase, catalase and glutathione peroxidase activities, decreased malondialdehyde levels and considerably reduced histopathological changes. Histopathological, immunohistochemical and Western blot analyses also demonstrated that salidroside could reduce the appearance of necrotic regions and expression of caspase-3 and hypoxia-inducible factor-1α in liver tissue.

Conclusions

Salidroside protected liver tissue from the oxidative stress elicited by d-galactosamine and lipopolysaccharide. The hepatoprotective mechanism of salidroside appear to be related to antioxidant activity and inhibition of hypoxia-inducible factor-1α.

Therapeutic use of cytoprotective agents in canine and feline hepatobiliary disease

Many medicinal, nutraceutical, and botanic extracts have been used as cytoprotective agents in liver disease. This article explains the mechanisms of action, pertinent pharmacokinetics, side effects, and clinical indications for the use of S-adenosylmethionine, N-acetylcysteine, ursodeoxycholic acid, silymarin, and vitamin E. The literature pertaining to in vitro studies, laboratory animal models, and human and veterinary clinical trials is reviewed with regards to the efficacy and use of these cytoprotective agents in hepatobiliary disease.

Attenuation of cyclosporine A-induced testicular and spermatozoal damages associated with oxidative stress by ellagic acid

This study was conducted to investigate the possible protective effect of ellagic acid (EA) on cyclosporine A (CsA)-induced testicular and spermatozoal damages associated with oxidative stress in male rats. Forty adult male Sprague-Dawley rats were divided into 4 groups of 10 animals each. Control group was used as placebo. Cyclosporine group received CsA at the dose of 15 mg/kg/day. Ellagic acid group was treated with EA (10 mg/kg/day). Cyclosporine plus ellagic acid group received CsA+EA. Reproductive organs were weighed and epididymal sperm characteristics and histopathological structure of testes were examined along with malondialdehyde (MDA) and glutathione (GSH) levels, glutathione-peroxidase (GSH-Px) and catalase (CAT) activities in testicular tissue. CsA significantly decreased the weights of testes and ventral prostate, epididymal sperm concentration, motility, testicular tissue glutathione (GSH), glutathione-peroxidase (GSH-Px) and catalase (CAT), diameters of seminiferous tubules and germinal cell layer thickness, and it significantly increased malondialdehyde (MDA) level and abnormal sperm rates along with degeneration, necrosis, immature germ cells, congestion and atrophy in testicular tissue. However, the CsA plus EA treatment attenuated all the CsA-induced negative changes observed in the testicular tissue, sperm and oxidant/antioxidant parameters. In conclusion, CsA-induced oxidative stress leads to the structural and functional damages in the testicular tissue and sperm quality of rats, and also EA has a protective effect on these damages.

Erdosteine modulates radiocontrast-induced hepatotoxicity in rat

It has been suggested that reactive oxygen species (ROS) plays an important role in radio contrast media (RCM)-induced ischemia reperfusion tissue injury although antioxidants may have protective effects on the injury. We investigated the effects of erdosteine as an antioxidant agent on RCM-induced liver toxicity in rats by evaluation of lipid peroxidation (as TBARS), catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH) and glutathione peroxidase (GSH-Px) values and histological evaluation. Twenty-one rats were equally divided into three groups as follows: control, RCM, and RCM plus erdosteine. RCM was intraperitoneally administered for 1 day. Erdosteine was administered orally for 2 days after RCM administration. Liver samples were taken from the rats and they homogenized in a motor-driven tissue homogenizer. TBARS levels were significantly (p < 0.005) higher in RCM group than in control although SOD activities significantly (p < 0.05) decreased in RCM group. TBARS levels were lower in RCM plus erdosteine group than in control although SOD activity and GSH level increased (p < 0.05) in liver as compared to RCM alone. Erdosteine showed also histopathological protection (p < 0.0001) against RCM induced hepatotoxicity. GSH-Px and CAT activities were not statistically changed by the erdosteine. According to our results, it can be concluded that radiocontrast media can induce oxidative stress in liver as suggested by previous studies. Erdosteine seems to be protective agent on the radiocontrast media-induced liver toxicity by inhibiting the production of ROS via the enzymatic antioxidant system.