Protective effects of N-acetyl-L-cysteine against acute carbon tetrachloride hepatotoxicity in rats

A comparison of the potential of melatonin and tryptophan to ameliorate CCl4-induced hepatic and renal toxicity in Wistar rats

CCl4 causes oxidative injury, fatty degeneration, fibrosis of the liver, renal failure, and even hepatocellular and renal carcinoma. Certain substances have the potential to neutralize the harmful effects of CCl4, so it will lead to numerous beneficial effects. Melatonin (MEL) is a powerful antioxidant that regulates circadian rhythm and has beneficial effects on organism; tryptophan (TRP) is its precursor necessary for the synthesis of MEL. The aim of the current study was to determine whether MEL and TRP, have protective effects during subchronic application of CCl4 to the liver and kidneys. Results suggest that CCl4 led to decrease of total proteins, albumins, globulins, erythrocytes, hemoglobin, and hematocrit; and increase of creatinine, AST, ALT values, and leukocytes. MEL and TRP both showing protective effects on regulation of serum proteins, albumins, globulins, A/G, AST, ALT, and creatinine levels. TRP had been shown to have potential in regulation of disbalanced hematological parameters caused by CCl4. TRP had beneficial effects on hepatocyte morphology in term of beaded chromatin and preserved cell morphology. Overall, oral supplementation of TRP had better protective effects on liver/kidneys compared to MEL.

Enhancing the efficacy of low doses of N-acetyl-L-cysteine in mitigating CCl4-induced hepatotoxicity in animal model using physical cold plasma

Liver diseases have become widespread especially due to various factors of modern life. Although the effect of N-acetyl-L-cysteine (NAC) is investigated in the recovery of liver damage, gas plasma therapy can be identified as a promising candidate. Our study aimed to enhance the effectiveness of ineffective doses of NAC in stopping CCl4-induced hepatotoxicity in rats by physical cold plasma. The plasma-treated NAC (PTN) structural changes were investigated through FTIR and LCMS/MS analysis. It was observed that the PTN consists of various chemical bioproducts with different molecular weights. We investigated an ineffective dose of NAC and its parallel effect through the administration of PTN on liver and kidney morphology and several biochemical factors including ALT, AST, and ALP. Additionally, we examined oxidative stress, antioxidant parameters, and glutathione (GSH) levels. Results showed that PTN exhibited greater antioxidant properties and increased GSH levels, contributing to its therapeutic effects. Also, the antioxidant enzymes and oxidative stress activities improved after receiving PTN. It also enhanced histological parameters, although various damages were detected in both liver and kidney tissues after CCl4 injection, PTN remarkably prevented the tissue changes caused by CCl4. PTN could protect against liver damage even at a very low dose of NAC, acting as a prophylactic drug with a high margin of safety for hepatotoxicity.

Heat hardening enhances metabolite-driven thermoprotection in the Mediterranean mussel Mytilus galloprovincialis

Introduction: Temperature affects organisms' metabolism and ecological performance. Owing to climate change, sea warming constituting a severe source of environmental stress for marine organisms, since it increases at alarming rates. Rapid warming can exceed resilience of marine organisms leading to fitness loss and mortality. However, organisms can improve their thermal tolerance when briefly exposed to sublethal thermal stress (heat hardening), thus generating heat tolerant phenotypes. Methods: We investigated the "stress memory" effect caused by heat hardening on M. galloprovincialis metabolite profile of in order to identify the underlying biochemical mechanisms, which enhance mussels' thermal tolerance. Results: The heat hardening led to accumulation of amino acids (e.g., leucine, isoleucine and valine), including osmolytes and cytoprotective agents with antioxidant and anti-inflammatory properties that can contribute to thermal protection of the mussels. Moreover, proteolysis was inhibited and protein turnover regulated by the heat hardening. Heat stress alters the metabolic profile of heat stressed mussels, benefiting the heat-hardened individuals in increasing their heat tolerance compared to the non-heat-hardened ones. Discussion: These findings provide new insights in the metabolic mechanisms that may reinforce mussels' tolerance against thermal stress providing both natural protection and potential manipulative tools (e.g., in aquaculture) against the devastating climate change effects on marine organisms.

Effects of N-acetyl-l-cysteine on heat stress-induced oxidative stress and inflammation in the hypothalamus of hens

The purpose of this study was to discuss the effects of N-acetyl-l-cysteine (NAC) on heat stress-induced oxidative stress and inflammation in the hypothalamus of hens in different periods. A total of 120 Hy-Line variety brown laying hens (12 weeks old) were randomly assigned to 4 groups with 6 replicates. The control group (C group) (22 ± 1 °C) received a basal diet, the NAC-treated group (N group) (22 ± 1 °C) received a basal diet with 1000 mg/kg NAC, and 2 heat-stressed groups (36 ± 1 °C for 10 h per day and 22 ± 1 °C for the remaining time) were fed a basal diet (HS group) or a basal diet with 1000 mg/kg NAC (HS + N group) for 21 consecutive days. The influence of NAC on histologic changes, oxidative stress and proinflammatory cytokine production was measured and analysed in hens with heat stress-induced hypothalamic changes. NAC effectively alleviated the hypothalamic morphological changes induced by heat stress. In addition, NAC attenuated the activity of the Nf-κB pathway activated by heat stress and decreased the expression of the proinflammatory cytokines IL-6, IL-18, TNF-α, IKK, and IFN-γ. In addition, NAC treatment regulated the expression of HO-1, GSH, SOD2 and PRDX3 by regulating the activity of Nrf2 at different time points to resist oxidative stress caused by heat exposure. In summary, dietary NAC may be an effective candidate for the treatment and prevention of heat stress-induced hypothalamus injury by preventing Nf-κB activation and controlling the Nrf2 pathway.

S-Methylcysteine (SMC) Ameliorates Intestinal, Hepatic, and Splenic Damage Induced by Cryptosporidium parvum Infection Via Targeting Inflammatory Modulators and Oxidative Stress in Swiss Albino Mice

Cryptosporidiosis has been proposed to be one of the major causes of diarrhoeal disease in humans worldwide that possesses zoonotic concern. Thereby, this study investigated the potential effects of s-Methylcysteine (SMC) on the parasite in vivo followed by the measurement of cytokines, oxidative stress parameters, and an investigation of the major histopathological changes. Sixty male Swiss albino mice weighing 20-25 g were allocated equally into five groups and orally administered saline only (control), SMC only (SMC50) (50 mg/kg b.w.), and 10⁴Cryptosporidium parvum oocysts per mouse via an esophageal tube (C + ve untreated). The fourth and fifth groups (C + SMC25, C + SMC50) administrated 10⁴C. parvum oocysts combined with SMC25 (low dose) and 50 (high dose) mg/kg b.w., respectively. At days 7 and 14 post-infection (PI), the feces was collected from each group in order to count C. parvum oocysts. After two weeks of treatment, the animals were euthanized and the serum was collected for biochemical analysis. Next, the intestinal, spleen, and liver sections were dissected for histopathological examination. The results revealed lower oocyst numbers in the C + SMC25 and C + SMC50 groups compared to the infected untreated group. Moreover, higher doses of SMC treatment significantly reduced the enteritis induced by C. parvum in a dose-dependent manner. The hepatic lesions were also mitigated as demonstrated in C + SMC25 and C + SMC50 groups unlike the infected group via lowering the serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) enzymes and increasing albumin and globulin serum levels. SMC administration also reduced cytokines production (SAP, TNF-α, IL-6, and IFN-γ) mediated by Cryptosporidium infection in contrast to the infected untreated group. There were marked lymphoid depletion and amyloidosis observed in the infected untreated group, while the treated groups showed obvious increase in the lymphoid elements. Moreover, the scoring of intestinal parasites, hepatic, and splenic lesions in the SMC-treated groups exhibited significantly lower pathological lesions in different organs in a dose-dependent manner, compared to the infected untreated group. Our results also revealed a significant change in the malondialdehyde content with an elevation of glutathione and superoxide dismutase in the intestines collected from C + SMC25 and C + SMC50 mice relative to the untreated group. Taken together, our results indicated that SMC could be a promising effective compound for treating and declining C. parvum infestation via restoring structural alterations in different tissues, enhancing antioxidant enzymes, and suppressing the cytokines liberation.

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.

Gamma-Glutamylcysteine Ethyl Ester Protects against Cyclophosphamide-Induced Liver Injury and Hematologic Alterations via Upregulation of PPARγ and Attenuation of Oxidative Stress, Inflammation, and Apoptosis

Gamma-glutamylcysteine ethyl ester (GCEE) is a precursor of glutathione (GSH) with promising hepatoprotective effects. This investigation aimed to evaluate the hepatoprotective effects of GCEE against cyclophosphamide- (CP-) induced toxicity, pointing to the possible role of peroxisome proliferator activated receptor gamma (PPARγ). Wistar rats were given GCEE two weeks prior to CP. Five days after CP administration, animals were sacrificed and samples were collected. Pretreatment with GCEE significantly alleviated CP-induced liver injury by reducing serum aminotransferases, increasing albumin, and preventing histopathological and hematological alterations. GCEE suppressed lipid peroxidation and nitric oxide production and restored GSH and enzymatic antioxidants in the liver, which were associated with downregulation of COX-2, iNOS, and NF-κB. In addition, CP administration significantly increased serum proinflammatory cytokines and the expression of liver caspase-3 and BAX, an effect that was reversed by GCEE. CP-induced rats showed significant downregulation of PPARγ which was markedly upregulated by GCEE treatment. These data demonstrated that pretreatment with GCEE protected against CP-induced hepatotoxicity, possibly by activating PPARγ, preventing GSH depletion, and attenuating oxidative stress, inflammation, and apoptosis. Our findings point to the role of PPARγ and suggest that GCEE might be a promising agent for the prevention of CP-induced liver injury.

Cysteic Acid in Dietary Keratin is Metabolized to Glutathione and Liver Taurine in a Rat Model of Human Digestion

Poultry feathers, consisting largely of keratin, are a low-value product of the poultry industry. The safety and digestibility of a dietary protein produced from keratin (KER) was compared to a cysteine-supplemented casein-based diet in a growing rat model for four weeks. KER proved to be an effective substitute for casein at 50% of the total dietary protein, with no changes in the rats' food intake, weight gain, organ weight, bone mineral density, white blood cell counts, liver glutathione, or blood glutathione. Inclusion of KER in the diet reduced total protein digestibility from 94% to 86% but significantly increased total dietary cysteine uptake and subsequent liver taurine levels. The KER diet also significantly increased caecum weight and significantly decreased fat digestibility, resulting in a lower proportion of body fat, and induced a significant increase in blood haemoglobin. KER is therefore a safe and suitable protein substitute for casein, and the cysteic acid in keratin is metabolised to maintain normal liver and blood glutathione levels.

Protective effects of L-carnitine, N-acetylcysteine and genistein in an experimental model of liver fibrosis

AIM

Liver fibrosis is a reversible wound-healing response that occurs following liver injury. In this study, we aimed to investigate the possible protective effects of L-carnitine, N-acetylcysteine and genistein in liver fibrosis induced by carbon tetrachloride (CCl4). In addition, the effects of these agents were compared in the same study.

METHODS

In this study, rats were randomly allocated into 8 groups, consisting of 10 rats each, as follows: a control group, CCl4, L-carnitine, N-acetylcysteine, genistein, CCl4 and L-carnitine, CCl4 and N-acetylcysteine, and CCl4 and genistein. At the end of 6 weeks, blood and liver tissue specimens were collected. Alanine aminotransferase (ALT); aspartate aminotransferase (AST); complete blood count, tumor necrosis factor-α (TNF-α); platelet-derived growth factor-BB (PDGF-BB); interleukin-6 (IL-6); liver glutathione level; oxidant/antioxidant status; scores of hepatic steatosis, necrosis, inflammation, and fibrosis; and the expression of α-smooth muscle actin were studied.

RESULTS

Although the ALT and AST values in the group administered CCl4 were significantly higher than in all the other groups (P<0.05), there was no significant difference between the control group and the groups administered CCl4 combined with L-carnitine, N-acetylcysteine and genistein (P>0.05). There were significant differences in the levels of TNF-α, PDGF-BB and IL-6 (P<0.05) between the CCl4 group and the groups with L-carnitine, N-acetylcysteine and genistein added to CCl4. N-acetylcysteine and genistein had positive effects on the oxidant/antioxidant status and on liver necrosis and fibrosis scores.

CONCLUSIONS

In our study, L-carnitine, N-acetylcysteine and genistein showed significant protective effects in liver fibrosis induced by CCl4.

The protective effects of n-acetylcysteine against acute hepatotoxicity

OBJECTIVES

N-acetylcysteine (NAC) increases tissue levels of glutathione and has been widely investigated as a protective and antioxidative agent. This study evaluated the protective effect of NAC on under carbon tetrachloride (CCl4)-induced acute liver injury in the rat.

METHODS

Three-month-old Sprague-Dawley rats were intraperitoneally administered 4 mL/kg CCl4 (1:1 dissolved in olive oil, group 1) or 4 mL/kg CCl4 + NAC 150 mg/kg, 3 and 6 h after CCL4 (group 2) or 4 mL/kg olive oil (group 3, control). Twenty-four hours after administering CCl4, all of the rats were sacrificed. Biochemical assessment of serum transaminases and malonaldehyde (MDA) and tissue MDA, myeloperoxidase (MPO), and nitric oxide was done. Histopathological assessments were performed.

RESULTS

Serum transaminases and tissue and serum MDA and tissue MPO were all increased in group 1 compared to control and were significantly decreased in the group treated with NAC. Histopathological comparison of the groups showed a decrease in congestion, polymorphonuclear leukocytes, mononuclear leukocytes, vacuolar degeneration of hepatocyte, and hepatocellular necrosis in the group treated with NAC.

CONCLUSION

Our results suggest that NAC prevents experimental acute hepatic failure by preventing oxidative stress.

Bio-distribution and in vivo antioxidant effects of cerium oxide nanoparticles in mice

Cerium oxide nanoparticles have oxygen defects in their lattice structure that enables them to act as a regenerative free radical scavenger in a physiological environment. We performed a comprehensive in vivo analysis of the biological distribution and antioxidant capabilities of nanoceria administered to mice perorally (PO), intravenously (IV), or intraperitoneally (IP) by dosing animals weekly for 2 or 5 weeks with 0.5 mg kg(-1) nanoceria. Next, we examined if nanoceria administration would decrease ROS production in mice treated with carbon tetrachloride (CCl(4)). Our results showed that the most extensive and cumulative nano-deposition was via IV and IP administered while PO administration showed mice excreted greater than 95% of their nanoceria within 24 h. Organ deposition for IV and IP mice was greatest in the spleen followed by the liver, lungs, and kidneys. Elimination for all administration routes was through feces. Nanoceria administration showed no overt toxicity, however, WBC counts were elevated with IV and IP administration. Our in vivo studies show that nanoceria administration to mice with induced liver toxicity (by CCl(4)) showed similar findings to mice treated with N-acetyl cystine (NAC), a common therapeutic to reduce oxidative stress. Taken together, our studies show that nanoceria remains deposited in tissues and may decrease ROS, thereby suggesting that cerium oxide nanoparticles may be a useful antioxidant treatment for oxidative stress.

Protective effect of fermented sea tangle against ethanol and carbon tetrachloride-induced hepatic damage in Sprague-Dawley rats

Sea tangle has long been used as Korean folk remedy to promote material health, and is one of the popular dietary supplement. This study was designed to evaluate the protective effect of fermented sea tangle (FST) against ethanol and carbon tetrachloride (CCl(4))-induced hepatotoxicity in rats. Sprague-Dawley rats were orally treated with FST (25, 250, 2500 mg/kg/day) with administration of ethanol (5 mL/kg) for 13 weeks and the single intraperitoneal (i.p.) dose of 50% CCl(4) (5 mL/kg/day, CCl(4) in olive oil) at 12 week, and repeated i.p. dose of 20% CCl(4) (2 mL/kg/day) for 1 week. Hepatotoxicity was evaluated by measuring the serum levels of glutamic pyruvate transaminase (GPT), gamma glutamyl transpeptidase (gamma-GT) and malondialdehyde (MDA) as well as the tissue levels of antioxidant enzyme such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Ethanol and CCl(4)-induced the rat liver damage, and significantly increased (p<0.05) the GPT, gamma-GT and MDA levels, and decreased the SOD, CAT and GPx levels. However, treatment with FST could decrease serum GPT, gamma-GT, and MDA levels significantly in plasma, and increase the activities of SOD, CAT, and GPx in liver tissues compared with ethanol and CCl(4)-treated group.

Effects of a preparation of combined glutathione-enriched yeast and rice embryo/soybean extracts on ethanol hangover

The effects of a preparation of combined glutathione-enriched yeast (GEY) and rice embryo/soybean (RES) extracts (20:1), GEY/RES, on experimentally induced ethanol hangover were investigated in male Sprague-Dawley rats. To evaluate the preventive effects on hangover, rats were orally administered GEY/RES (50/2.5, 100/5, or 200/10 mg/kg) for 2 weeks. At 30 minutes after the final treatment, they were challenged with 3 mL/kg ethanol (15 mL of 20% in water/kg). The blood concentrations of alcohol and acetaldehyde were analyzed up to 7 hours postchallenge. Hepatic mRNA expression levels of alcohol-metabolizing enzymes, alcohol dehydrogenase (ADH), cytochrome P450 type 2E1 (CYP2E1), and aldehyde dehydrogenase (ALDH), were determined by real-time polymerase chain reaction. Additional rats were challenged with ethanol and, 60 minutes later, administered GEY/RES to evaluate alcohol clearance. Pretreatment with GEY/RES for 2 weeks reduced the blood concentrations of alcohol and acetaldehyde in a dose-dependent manner, lowering by 29.5% and 54.6% at the highest dose (200/10 mg/kg), respectively. The expressions of mRNAs for ADH and ALDH, the major alcohol-metabolizing enzymes, were markedly increased in the livers of rats administered GEY/RES for 2 weeks, whereas CYP2E1 mRNA was suppressed. Postchallenge treatment with GEY/RES enhanced the alcohol clearance rate by lowering blood concentrations of alcohol and acetaldehyde by 24% and 26.6%, respectively, for the highest dose group. GEY/RES remarkably eliminated 2,2-diphenyl-1-picrylhydrazyl hydrate radical and FeCl(3)-mediated lipid peroxidation in vitro and attenuated hepatic lipid accumulation following ethanol administration in vivo. Therefore, it is suggested that GEY/RES reduces the blood concentrations of alcohol and acetaldehyde not only by modulating alcohol-metabolizing enzymes, but also by exerting its antioxidant activity, and that GEY/RES could be a promising candidate for improvements of alcoholic hangover.

Can N-Acetylcysteine Preserve Peritoneal Function and Morphology in Encapsulating Peritoneal Sclerosis?

Long-term use of the peritoneum as a dialysis membrane results in progressive irreversible dysfunction, described as peritoneal fibrosis. Oxidative stress during peritoneal dialysis has been established in many studies. Generation of reactive oxygen species (ROS) by conventional peritoneal dialysis solutions, regardless of whether produced by high glucose, angiotensin II, or glucose degradation products may be responsible for progressive membrane dysfunction.

The well-known antioxidant molecule N-acetylcysteine (NAC) is capable of direct scavenging of ROS. The aim of the present study was to investigate the effect of NAC therapy on both progression and regression of encapsulating peritoneal sclerosis (EPS).

We divided 49 nonuremic Wistar albino rats into four groups: Control group—2 mL isotonic saline intraperitoneally (IP) daily for 3 weeks; CG group—2 mL/200 g 0.1% chlorhexidine gluconate (CG) and 15% ethanol dissolved in saline injected IP daily for a total of 3 weeks; Resting group—CG (weeks 1 – 3), plus peritoneal resting (weeks 4 – 6); NAC-R group—CG (weeks 1 – 3), plus 2 g/L NAC (weeks 4 – 6).

At the end of the experiment, all rats underwent a 1-hour peritoneal equilibration test with 25 mL 3.86% PD solution. Dialysate-to-plasma ratio (D/P) urea, dialysate white blood cell count (per cubic milliliter), ultrafiltration (UF) volume, and morphology changes of parietal peritoneum were examined.

The CG group progressed to encapsulating peritoneal sclerosis, characterized by loss of UF, increased peritoneal thickness, inflammation, and ultimately, development of fibrosis. Resting produced advantages only in dialysate cell count; with regard to vascularity and dialysate cell count, NAC was more effective than was peritoneal rest. Interestingly, we observed no beneficial effects of NAC on fibrosis. That finding may be a result of our experimental severe peritoneal injury model. However, decreased inflammation and vascularity with NAC therapy were promising results in regard to membrane protection.