Effects of omega-3 supplementation on anxiety-like behaviors and neuroinflammation in Wistar rats following cafeteria diet-induced obesity.

ABSTRACTObjetives: Omega-3 (n3) fatty acids have been studied as an option to alleviate the harmful effects of obesity. However, its role in obesity-related behavioral changes is still controversial. This study aimed to evaluate the effects of n3 on behavior and neuroinflammation in obese animals. Methods: Male Wistar rats were divided into four groups: control diet (CT), CT+n3, cafeteria diet (CAF), and CAF+n3. Diet was administered for 13 weeks, and n3 was supplemented during the last 5 weeks. Metabolic and biochemical parameters were evaluated, as well as anxiety-like behaviors. Immunoblots were conducted in the animals' cerebral cortex and hippocampus to assess changes in neuroinflammatory markers.Results: CAF-fed animals showed higher weight gain, visceral adiposity, fasting glucose, total cholesterol, triglycerides, and insulin levels, and n3 improved the lipid profile and restored insulin sensitivity. CAF-fed rats showed anxiety-like behaviors in the open field and light-dark box tasks but not in the contextual aversive conditioning. Omega-3 did not exert any effect on these behaviors. Regarding neuroinflammation, diet and supplementation acted in a region-specific manner. In the hippocampus, CAF reduced claudin-5 expression with no effect of n3, indicating a brain-blood barrier disruption following CAF. Furthermore, in the hippocampus, the glial fibrillary acidic protein (GFAP) and toll-like receptor 4 (TLR-4) were reduced in treated obese animals. However, n3 could not reverse the TLR-4 expression increase in the cerebral cortex.Discussion: Although n3 may protect against some neuroinflammatory manifestations in the hippocampus, it does not seem sufficient to reverse the increase in anxiolytic manifestations caused by CAF.

DHA/EPA supplementation decreases anxiety-like behaviour, but it does not ameliorate metabolic profile in obese male rats.

Obesity is a major public health problem that predisposes to several diseases and higher mortality in patients with COVID-19. Obesity also generates neuroinflammation, which predisposes to the development of neuropsychiatric diseases. Since there is a lack of effective treatments for obesity, the search for new strategies to reverse its consequences is urgent. In this perspective, the anti-inflammatory properties of omega-3 polyunsaturated fatty acids such as DHA/EPA might reduce the harmful effects of obesity. Here, we used the cafeteria diet (CAF) model to induce obesity in Wistar rats. Animals received ultra-processed food for 20 weeks, and DHA/EPA supplementation (500 mg/kg per d) was performed between the 16th and the 20th week. At the end of the experiment, it was evaluated: body weight, visceral fat deposition, plasma glucose, insulin and triglycerides, and it was also measured the levels of inflammatory cytokines TNF-α and IL-6 in plasma and liver, and TNF-α in the prefrontal cortex. The elevated plus maze test was performed to analyse anxiety-like behaviour. Our results demonstrated that DHA/EPA could not reverse weight and fat gain and did not modify plasma dosages. However, there was a decrease in IL-6 in the liver (DHA/EPA effect: P = 0.023) and TNF-α in the brain (CAF compared with CAF + DHA/EPA, P < 0.05). Also, there was a decrease in the anxiety index in CAF + DHA/EPA compared with the CAF group (P < 0.01). Thus, DHA/EPA supplementation is helpful to reverse the consequences of obesity in the brain.

Neuroinflammatory responses following zinc or branched-chain amino acids supplementation in obese rats.

The excessive production of pro-inflammatory mediators, characteristic of obesity, leads to neuroinflammation. Zinc (Zn) and the branched-chain amino acids (BCAA) are supplements known for their immunomodulatory properties. Our goal was to evaluate if Zn or BCAA supplementation can affect long-term recognition memory and neuroinflammatory parameters of obese rats after a high-fat diet (HFD). Three-month-old Wistar rats were divided into six groups: Standard diet (SD) + vehicle; SD + Zn; SD + BCAA; High-fat diet (HFD) + vehicle; HFD + Zn; and HFD + BCAA. Diets were administrated for 19 weeks, Zn (1,2 mg/kg/day) or BCAA (750 mg/kg/day) supplementation was conducted in the last 4 weeks. Long-term recognition memory was evaluated by the novel object recognition test. IL-1ß immunoreactivity in the cortex and hippocampus, and IL-6 levels in the cortex tissue were assessed. Astrogliosis were evaluated through GFAP + cell count and morphological analysis (Sholl Method). Zn supplementation improved object recognition memory in HFD-fed rats, which was not observed following BCAA supplementation. The levels of IL-6 in the cerebral cortex were higher after HFD, which was not diminished after neither supplementation. Obesity also led to increased IL-1ß immunoreactivity in the cerebral cortex and hippocampus, which was reduced by Zn. BCAA supplementation also diminished IL-1ß immunoreactivity, but only in the hippocampus. We also showed that astrocyte reactivity caused by HFD is area-dependent, being the cerebral cortex more susceptible to the diet. Even though BCAA and Zn can affect IL-1ß immunoreactivity and astrocyte morphology, only Zn improved memory. Future studies are needed to clarify the pathways by which Zn improves cognition in obesity.

Food Selection of Cafeteria Diet Affects Memory Dysfunction Related to Obesity.

Cafeteria diet (CAF) mimics human Western diet and has been used in animal models to study obesity. The purpose of this study is to demonstrate that our CAF model induces metabolic disorder related to obesity and affects recognition memory in Wistar rats. We also compared the intake of two different soft drinks, as part of the CAF, on recognition memory. Our results demonstrate that CAF-fed rats increased weight gain and visceral adiposity, and exhibited hyperglycemia, hypertriglyceridemia, high leptin and low insulin plasma levels. Moreover, CAF animals showed higher lipid peroxidation in the liver and developed non-alcoholic fatty liver disease. Surprisingly, the group fed with cola-based soft drinks presented an improvement in recognition memory, whereas animals fed with orange-based soft drinks showed worse performance in this task. Our data indicates that CAF induces obesity and affects recognition memory, but the composition of the diet interfere when the neurological function is evaluated.

Altered expression of COX-2 and TNF-α in patients with hepatocellular carcinoma.

BACKGROUND AND AIM: hepatocellular carcinoma is a type of cancer related with inflammation, as 90% of cases develop in a chronic inflammation condition. Excess inflammation can affect tissue homeostasis. Cytokines and inflammatory mediators are immunological components that can influence the functioning of cells and tissues. In addition, the estrogen receptor appears to play an important role in hepatocarcinogenesis. The aim of the study was to evaluate the expression of inflammatory markers and ER in patients with hepatocellular carcinoma. METHODS: data from 143 patients of ISCMPA were analyzed. Immunohistochemistry was performed of cyclooxygenase-2 enzyme (COX-2), nuclear factor kappa B (NF-κB), tumor necrosis factor alpha (TNF-α) and ER in paraffin-embedded hepatic tissue. The percentage of the stained area, intensity of staining and of the number of ER positive nuclei were evaluated using the ImageJ 1.50 software. RESULTS AND CONCLUSION: there was a significant difference between the groups in terms of the percentage of marked area (p = 0.040) for COX-2 and the intensity of staining of TNF-α (p = 0.030). No significant differences were observed in any of other parameters evaluated. In conclusion, COX-2 and TNF-α are possible markers that should be further studied to determine their immunohistochemical profile and role in HCC development.

Omega-3 fatty acids revert high-fat diet-induced neuroinflammation but not recognition memory impairment in rats.

Neuroinflammation is a consequence of overeating and may predispose to the development of cognitive decline and neurological disorders. This study aimed to evaluate the impact of omega-3 supplementation on memory and neuroinflammatory markers in rats fed a high-fat diet. Male Wistar rats were divided into four groups: standard diet (SD); standard diet + omega-3 (SD + O); high fat diet (HFD); and high fat diet + omega-3 (HFD + O). Diet administration was performed for 20 weeks and omega-3 supplementation started at the 16th week. HFD significantly increased body weight, while omega-3 supplementation did not modify the total weight gain. However, animals from the HFD + O group showed a lower level of visceral fat along with an improvement in insulin sensitivity following HFD. Thus, our results demonstrate a beneficial metabolic role of omega-3 following HFD. On the other hand, HFD animals presented an impairment in object recognition memory, which was not recovered by omega-3. In addition, there was an increase in GFAP-positive cells in the cerebral cortex of the HFD group, showing that omega-3 supplementation can be effective to decrease astrogliosis. However, no differences in GFAP number of cells were found in the hippocampus. We also demonstrated a significant increase in gene expression of pro-inflammatory cytokines IL-6 and TNF-α in cerebral cortex of the HFD group, reinforcing the anti-inflammatory role of this family of fatty acids. In summary, omega-3 supplementation was not sufficient to reverse the memory deficit caused by HFD, although it played an important role in reducing the neuroinflammatory profile. Therefore, omega-3 fatty acids may play an important role in the central nervous system, preventing the progression of neuroinflammation in obesity.

The effect of celecoxib on the development of diethylnitrosamine-induced liver tumors in rats.

BACKGROUND/AIMS: Hepatocellular carcinoma is one of the most commonly diagnosed malignant tumors in the world, and it typically has a poor prognosis. Extensive studies have examined the effects of non-steroidal anti-inflammatory drugs selective to COX-2 on the chemoprevention of various tumors. The objective of this study is to observe the effect of celecoxib on the development of liver tumors in rats. MATERIAL AND METHODS: Hepatocellular carcinoma was induced in a group of 75 rats with the carcinogen diethylnitrosamine. The animals were divided into 5 groups. Three groups received various doses of celecoxib, one group received indomethacin, and a control group received no non-steroidal selective anti inflammatory drugs. RESULTS: The experimental model was considered to be successful because 78% of the rats in the control group developed liver tumors. The number of neoplastic lesions was similar among the celecoxib, indomethacin and control groups, although the nodule diameter of the lesions was smaller in the celecoxib group. Better results were observed in animals that received celecoxib at doses of 6 and 9 mg/kg/ day; 4 rats in these groups did not show any neoplastic histological lesions, and a greater proportion of the nodules in the other animals in these groups were benign than in the groups that did not use celecoxib. CONCLUSIONS: These results suggest that celecoxib may play a role in modifying the natural history of hepatocellular carcinoma development.

Impact of cafeteria diet and n3 supplementation on the intestinal microbiota, fatty acids levels, neuroinflammatory markers and social memory in male rats.

OBJECTIVE: To assess the effects of omega-3 (n3) supplementation on intestinal microbiota, fatty acids profile, neuroinflammation, and social memory of cafeteria diet (CAF)-fed rats. METHODS: Male Wistar rats were fed with CAF for 20 weeks. Omega-3 (500 mg/kg/day) was supplemented between the 16th and 20th week. Colon morphology, intestinal microbiota composition, short-chain fatty acids (SCFA) and lipopolysaccharide (LPS) in the plasma, fatty acids profile, TLR-4 and claudin-5 expressions in the brain, and social memory were investigated. RESULTS: CAF reduced colon length, crypts' depth, and microbiota diversity, while n3 increased the Firmicutes/Bacteroidetes ratio. CAF increased SCFA plasma levels, but n3 reduced butyrate and isobutyrate in obese rats. LPS was increased in CAF-fed rats, and n3 decreased its levels. In the cerebral cortex, n3 increased caprylic, palmitic, stearic, tricosanoic, lignoceric, myristoleic, and linoleic acids. CAF increased palmitic acid and TLR-4 expression in the cerebral cortex while decreasing claudin-5 in the hippocampus. In the social memory test, CAF-fed animals showed greater social interaction with no effect of n3. CONCLUSIONS: The lack of n3 effect in some of the evaluated parameters may be due to the severity of the obesity caused by CAF. However, n3 reduced LPS levels, suggesting its ability to reverse endotoxemia.

Fish Oil - Omega-3 Exerts Protective Effect in Oxidative Stress and Liver Dysfunctions Resulting from Experimental Sepsis.

Background: Sepsis is a severe global health problem, with high morbidity and mortality. In sepsis, one of the main affected organs is the liver. Hepatic alterations characterize a negative prognostic. Omega-3 fatty acids (ω3), eicosapentaenoic acid, and docosahexaenoic acid, are part of the main families of polyunsaturated fatty acids. ω3 has been used in studies as sepsis treatment and as a treatment for non-alcoholic liver disease. Aim: We aimed to evaluate the effects of treatment with fish oil (FO) rich in ω3 on liver changes and damage resulting from experimental sepsis. Methodology: A model of severe sepsis in Wistar rats was used. Oxidative stress in the liver tissue was evaluated by means of tests of thiobarbituric acid reactive substances, 2,7-dihydrodichlorofluorescein diacetate , catalase, and glutathione peroxidase, in the serum TBARS, DCF, thiols and, to assess liver dysfunction, alanine aminotransferase and aspartate aminotransferase. Hepatic tissue damage was evaluated using H&E histology. Results: In assessments of oxidative stress in liver tissue, a protective effect was observed in the tests of TBARS, DCF, CAT, and GPx, when compared the sepsis versus sepsis+ω3 groups. Regarding the oxidative stress in serum, a protective effect of treatment with ω3 was observed in the TBARS, DCF, and thiols assays, in the comparison between the sepsis and sepsis+ω3 groups. ω3 had also a beneficial effect on biochemical parameters in serum in the analysis of ALT, creatinine, urea, and lactate, observed in the comparison between the sepsis and sepsis+ω3 groups. Conclusion: The results suggest ω3 as a liver protector during sepsis with an antioxidant effect, alleviating injuries and dysfunctions.

Treatment with aqueous extract from Croton cajucara Benth reduces hepatic oxidative stress in streptozotocin-diabetic rats.

Croton cajucara Benth is a plant found in Amazonia, Brazil and the bark and leaf infusion of this plant have been popularly used to treat diabetes and hepatic disorders. The present study was designed to evaluate the oxidative stress as well as the therapeutic effect of Croton cajucara Benth (1.5 mL of the C. cajucara extract i.g.) in rats with streptozotocin-induced diabetes. Croton cajucara Benth was tested as an aqueous extract for its phytochemical composition, and its antioxidant activity in vitro was also evaluated. Lipid peroxidation and superoxide dismutase, catalase, and glutathione reductase activities were measured in the hepatic tissue, as well as the presence activation of p65 (NF-κB), through western blot. Phytochemical screening of Croton cajucara Benth detected the presence of flavonoids, coumarins and alkaloids. The extract exhibited a significant antioxidant activity in the DPPH-scavenging and the hypoxanthine/xanthine oxidase assays. Liver lipid peroxidation increased in diabetic animals followed by a reduction in the Croton-cajucara-Benth-treated group. There was activation of p65 nuclear expression in the diabetic animals, which was attenuated in the animals receiving the Croton cajucara Benth aqueous extract. The liver tissue in diabetic rats showed oxidative alterations related to the streptozotocin treatment. In conclusion the Croton cajucara Benth aqueus extract treatment effectively reduced the oxidative stress and contributed to tissue recovery.

The effect of taurine on hepatic steatosis induced by thioacetamide in zebrafish (Danio rerio).

BACKGROUND: Nonalcoholic fatty liver disease is one of the most prevalent forms of chronic liver disease in the Western world. Taurine is a conditionally essential amino acid in humans that may be a promising therapy for treating this disease. AIM: To evaluate the effect of taurine on hepatic steatosis induced by thioacetamide in Danio rerio. METHODS: Animals were divided into four groups: control (20 µl of saline solution), taurine (1,000 mg/kg), thioacetamide (300 mg/kg), and the taurine-thioacetamide group (1,000 + 300 mg/kg). Thioacetamide was injected intraperitoneally three times a week for 2 weeks. The mRNA expression, lipoperoxidation, antioxidant enzymatic activity, and histological analyses were evaluated in the liver and the triglyceride content was assessed in the serum. RESULTS: Thioacetamide injection induced steatosis, as indicated by histological analyses. The lipoperoxidation showed significant lipid damage in the thioacetamide group compared to the taurine-thioacetamide group (p < 0.001). Superoxide dismutase (SOD) activity in the taurine-thioacetamide group (5.95 ± 0.40) was significantly increased compared to the thioacetamide group (4.14 ± 0.18 U SOD/mg of protein) (p < 0.001). The mRNA expression of SIRT1 (0.5-fold) and Adiponectin receptor 2 (0.39-fold) were lower in the thioacetamide group than the control (p < 0.05). TNF-α mRNA expression was 6.4-fold higher in the thioacetamide group than the control (p < 0.05). SIRT1 mRNA expression was 2.6-fold higher in the taurine-thioacetamide group than in the thioacetamide group. CONCLUSIONS: Taurine seems to improve hepatic steatosis by reducing oxidative stress and increasing SIRT1 expression.

Zinc Supplementation Partially Decreases the Harmful Effects of a Cafeteria Diet in Rats but Does Not Prevent Intestinal Dysbiosis.

Zinc (Zn) plays an important role in metabolic homeostasis and may modulate neurological impairment related to obesity. The present study aimed to evaluate the effect of Zn supplementation on the intestinal microbiota, fatty acid profile, and neurofunctional parameters in obese male Wistar rats. Rats were fed a cafeteria diet (CAF), composed of ultra-processed and highly caloric and palatable foods, for 20 weeks to induce obesity. From week 16, Zn supplementation was started (10 mg/kg/day). At the end of the experiment, we evaluated the colon morphology, composition of gut microbiota, intestinal fatty acids, integrity of the intestinal barrier and blood-brain barrier (BBB), and neuroplasticity markers in the cerebral cortex and hippocampus. Obese rats showed dysbiosis, morphological changes, short-chain fatty acid (SCFA) reduction, and increased saturated fatty acids in the colon. BBB may also be compromised in CAF-fed animals, as claudin-5 expression is reduced in the cerebral cortex. In addition, synaptophysin was decreased in the hippocampus, which may affect synaptic function. Our findings showed that Zn could not protect obese animals from intestinal dysbiosis. However, an increase in acetate levels was observed, which suggests a partial beneficial effect of Zn. Thus, Zn supplementation may not be sufficient to protect from obesity-related dysfunctions.

Effect of Melatonin on the Reduction of Hepatic Steatosis and Intestinal Leptin Expression in Zebrafish Exposed to Fructose.

Melatonin is a hormone related to circadian rhythms and has potential clinical applications. Our objectives were to verify the effect of melatonin on the liver of zebrafish exposed to fructose and evaluate the expression of appetite-related genes (leptin, ghrelin, and melanocortin receptor 4 [MC4R]). Animals were divided into three groups: control (CG, n = 25), fructose (FG, n = 25), and fructose+melatonin (FMG, n = 25). The study was carried out in 8 weeks. FG and FMG were exposed to 2% fructose and FMG treated with 1 µM of melatonin. Histological liver studies and gene expression analyses of Leptin, Ghrelin, and MC4R (liver and intestines) were performed. FG developed hepatic steatosis, which did not occur with CG and FMG. Genetic expression of hepatic leptin and MC4R did not show significant difference among the groups. Animals exposed to fructose (FG) presented an increased expression of intestinal leptin compared to those administered with melatonin. Animals exposed to fructose gained weight and developed an important hepatic steatosis, but melatonin reduced significantly the hepatic damage. Intestinal leptin showed increased expression in the group exposed to fructose.

Zinc Supplementation Decreases Obesity-Related Neuroinflammation and Improves Metabolic Function and Memory in Rats.

OBJECTIVE: The purpose of this study was to evaluate the effects of zinc (Zn) supplementation on metabolic and neuroinflammatory parameters in cafeteria diet (CAF)-induced obesity in Wistar rats. METHODS: Animals were divided into four groups: control diet (CT); CT+Zn; CAF; CAF+Zn. The diet was administered for 20 weeks; Zn treatment (10 mg/kg/d) started at week 16 and it was conducted until the end of the diet protocol. Weight gain, visceral fat, and plasma levels of glucose, triglycerides, insulin, TNF-α, and IL-6, as well as homeostatic model assessment of insulin resistance, were assessed. Glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1 (Iba-1) expression in the cerebral cortex and toll-like receptor 4 (TLR-4) in the cerebral cortex and hippocampus were evaluated. Memory was assessed by the novel object recognition test. RESULTS: CAF diet increased weight gain, visceral fat, and plasma glucose, triglyceride, and TNF-α levels. Zn reversed the hyperglycemia caused by CAF diet and reduced IL-6 levels. In the cerebral cortex, GFAP was similar between groups; Iba-1 was increased by CAF diet but reduced in the CAF+Zn group. Zn reduced CAF-dependent TLR-4 increase in the hippocampus but not in the cerebral cortex. CAF-fed animals showed impaired recognition memory, whereas Zn reversed it. CONCLUSIONS: These findings demonstrate that Zn partially reverted obesity-related metabolic dysfunction and reduced neuroinflammation and memory deficit caused by CAF diet.

Zinc supplementation reduces diet-induced obesity and improves insulin sensitivity in rats.

Rates of obesity have been growing at alarming rates, compromising the health of the world population. Thus, the search for interventions that address the metabolic repercussions of obesity are necessary. Here we evaluated the metabolic and antioxidant effects of zinc and branched-chain amino acids (BCAA) supplementation on obese rats. Male Wistar rats were fed either a high-fat/high-fructose diet (HFD) or a standard diet (SD) for 19 weeks. From the fifteenth week until the end of the experiment, HFD- and SD-fed rats received zinc (6 mg/kg) or BCAA (750 mg/kg) supplementation. Body weight, abdominal fat, lipid profile, blood glucose, insulin, leptin, and hepatic transaminases were evaluated. In the liver, superoxide dismutase and catalase activities and lipid peroxidation were also analyzed. HFD-fed animals showed increased weight gain, abdominal fat pad, plasma insulin, leptin, and triglycerides levels in comparison with SD-fed rats. Zinc supplementation reduced all these parameters, suggesting a beneficial role for the treatment of obesity. BCAA, on the other hand, did not show any beneficial effect. Liver antioxidant enzymes and hepatic transaminases plasma levels did not change among groups. Lipid peroxidation was higher in HFD-fed rats and was not reverted by zinc or BCAA supplementation. In conclusion, zinc supplementation may be a useful strategy for the treatment of the metabolic dysfunction associated with obesity.

Maternal feeding associated to post-weaning diet affects metabolic and behavioral parameters in female offspring.

Genetic and environmental factors related to maternal diet may predispose offspring to serious diseases. However, consequences of a maternal diet intervention during gestation and lactation, and its association with caloric restriction after weaning on the progeny are not completely known. In this context, the goal of the present study was to investigate how different maternal diets, control (CONT), hypercaloric (HD) or restrictive (RD) diets during gestation and lactation, may affect the metabolism and behavior of the offspring that was also submitted to RD. Experimental groups were abbreviated accordingly maternal/offspring diets: CONT/CONT, CONT/RD, RD/CONT, RD/RD, HD/CONT, HD/RD. Our results showed that glucose serum concentration is increased in mice from dams fed a HD. However, offspring from RD-fed dams showed lower insulin and leptin levels than the other groups, indicating a maternal diet effect. Moreover, animals from RD/CONT group showed a higher adipocyte area in comparison to both HD/CONT and CON/CONT. Offspring from RD-fed dams exhibited a decrease in lateral area locomotion in the open field test. Evaluation of anxiety-like behavior and recognition memory showed no significant difference among groups. Thus, maternal RD provides a beneficial response in metabolic parameters, but its effects on behavior is not completely clarified.

Low maternal care is associated with increased oxidative stress in the brain of lactating rats.

Maternal care is crucial for offspring development and licking/grooming patterns can be induced by sensorial, neuroendocrine, and metabolic variations in the CNS. Important brain functions, such as learning and memory, can be influenced by oxidative stress, which can also modulate pathophysiological processes (e.g., depression, anxiety, and other psychiatric disorders). This study evaluated oxidative stress in the hippocampus (HP), olfactory bulb (OB), and plasma in Low-Licking (LL) and High-Licking (HL) lactating rats through superoxide dismutase (SOD) and catalase (CAT) activities, DNA damage (comet assay), and dihydrodichlorofluorescein (DCF) oxidation assay. Results demonstrate that in the HP of LL, the activities of SOD and CAT were increased compared to HL. In the OB, the activities of SOD and CAT were also increased in LL. The comet assay in the HP showed that LL had higher levels of basal damage and increased levels of DNA breaks than HL. In the OB, LL also had higher levels of DNA damage. In the plasma, no difference was observed in either SOD or CAT activities, but the DCF oxidation assay revealed that LL had higher levels of ROS production than HL. In conclusion, we observed that LL mothers showed evidence of increased oxidative stress when compared to HL, suggesting that variations in maternal behavior might be related to these biochemical parameters.

Cirrhosis induces apoptosis in renal tissue through intracellular oxidative stress.

BACKGROUND: Renal failure is a frequent and serious complication in patients with decompensated cirrhosis. OBJECTIVES: We aimed to evaluate the renal oxidative stress, cell damage and impaired cell function in animal model of cirrhosis. METHODS: Secondary biliary cirrhosis was induced in rats by ligation of the common bile duct. We measured TBARS, ROS and mitochondrial membrane potential in kidney as markers of oxidative stress, and activities of the antioxidant enzymes. Relative cell viability was determined by trypan blue dye-exclusion assay. Annexin V-PE was used with a vital dye, 7-AAD, to distinguish apoptotic from necrotic cells and comet assay was used for determined DNA integrity in single cells. RESULTS: In bile duct ligation animals there was significant increase in the kidney lipoperoxidation and an increase of the level of intracellular ROS. There was too an increase in the activity of all antioxidant enzymes evaluated in the kidney. The percentage viability was above 90% in the control group and in bile duct ligation was 64.66% and the dominant cell death type was apoptosis. DNA damage was observed in the bile duct ligation. There was a decreased in the mitochondrial membrane potential from 71.40% ± 6.35% to 34.48% ± 11.40% in bile duct ligation. CONCLUSIONS: These results indicate that intracellular increase of ROS cause damage in the DNA and apoptosis getting worse the renal function in cirrhosis.

Hepatic nitrosative stress in experimental diabetes.

AIM: The effects of the inhibition of nitrosative stress by aminoguanidine in an experimental model of diabetes mellitus (DM) were investigated. METHODS: Twenty-one male Wistar rats were divided into three groups: control (CO), diabetic (DM), and diabetic treated with aminoguanidine (DM+AG). Aminoguanidine (aminoguanidine hemisulfate salt, Sigma Chemical Co., St. Louis, MO, USA) was used at a dose of 50 mg/kg (i.p.) during the last 30 days of the experiment. The expression levels of liver lipoperoxidation (TBARS - nmol/mg protein), inducible oxide nitric synthase (iNOS), nitrotyrosine and the NFκB nuclear transcription factor p65 were examined using western blot analysis. RESULTS: The DM group demonstrated an increase in lipoperoxidation and in the expression of iNOS, nitrotyrosine and p65. Aminoguanidine reduced hepatic lipid peroxidation and protein expression levels of iNOS, nitrotyrosine and p65. CONCLUSION: Aminoguanidine treatment reduces liver oxidative and nitrosative stress in diabetic animals. In addition, aminoguanidine reduced the expression of p65 in the liver.