Effects of cancer-induced cachexia and administration of L-glutathione on the intestinal mucosa in rat.

Walker-256 tumor is an experimental model known to promote cachexia syndrome, oxidative stress, and systemic inflammation. This study evaluated the duodenal mucosa of rats with Walker-256 tumor administered with 1% L-glutathione, intending to evaluate the damage caused by cancer-associated cachexia in the gastrointestinal tract and the effects of antioxidant administration on mucosal protection. Twenty-four 55-day-old male Wistar rats were distributed into four groups: control (C); control administered with 1% L-glutathione (C-GSH); Walker-256 tumor (W) and Walker-256 tumor administered with 1% L-glutathione (W-GSH). After 14 days of treatment, the duodenum was harvested for morphometric analysis of the mucosa, proliferation, apoptosis, immunostaining of varicosities immunoreactive (IR) to vasoactive intestinal peptide (VIP) and 5-HT-IR cells, and quantification of mast cells and goblet cells. Walker-256 tumor-bearing rats showed cachexia syndrome, mucosal atrophy, reduced cell proliferation, reduced 5-HT-IR cells, and increased goblet cells and VIPergic varicosities, which were not reversed by L-glutathione. On the other hand, L-glutathione caused a reduction of cells in apoptosis and mast cell recruitment, demonstrating a partial recovery of the damage detected in the intestinal mucosa.

Cancer-induced morphological changes in enteric glial cells in the jejunum of Walker-256 tumor-bearing rats.

Cancer-induced cachexia is associated with systemic inflammation and gastrointestinal dysfunction. How changes to cells of the enteric nervous system contribute to gut dysfunction in tumor development and cancer cachexia is unknown. Here, we tested the hypothesis that changes to enteric glia, a type of peripheral glia that surround enteric neurons and regulate gut homeostasis, are associated with tumor development and that supplementing with the antioxidant L-glutathione is protective against the changes induced. Immunohistochemistry for neurons, enteric glial cells and immune cells was performed in whole-mount preparations and frozen histological sections of the jejunum from 20 Wistar rats, distributed in 4 groups: control, tumor of Walker-256, control administered with 1 % L-glutathione, and tumor of Walker-256 administered with 1 % L-glutathione. Morphoquantitative analyses were made using Image-Pro® Plus 4.5 and ImageJ® 1.43° software. Tumor development significantly reduced neuronal and glial cell populations in the myenteric and submucosal plexuses and enlarged glial cell body area in the submucosal plexus. In contrast, tumors increased glia in the jejunal mucosa and this effect was accompanied by B-lymphocyte recruitment. GSH-supplemented diet was not sufficient to protect against changes to neurons and glia in the submucosal plexus but was partially protective in the myenteric plexus. L-glutathione had no effect on physiological parameters of cachexia but was sufficient to preserve enteric glial cell density in the myenteric plexus. These results suggest that changes to both enteric neurons and glia likely contribute to the gastrointestinal effects of tumor development and that oxidative stress contributes to these effects in the enteric nervous system.

L-glutathione 1% promotes neuroprotection of nitrergic neurons and reduces the oxidative stress in the jejunum of rats with Walker-256-bearing tumor.

AIMS: Our main goals were to investigate the effects of L-glutathione (1%) treatment in Walker-256 tumor-bearing rats by analyzing immunoreactive neurons (IR), responsive to the nNOS enzyme and 3-Nitrotyrosine, in their jejunum myenteric plexus. Moreover, the oxidative state and inflammatory process in these animals were investigated. METHODS: Four experimental groups were utilized: control (C), control treated with L-glutathione (CGT), Walker-256 tumor-bearing rats (TW), and Walker-256 tumor-bearing rats treated with L-glutathione (TWGT). After 14 days of tumor inoculation, the jejunum was collected for immunohistochemical techniques and assessment of oxidative status. Plasma was collected to evaluate oxidative status and measure cytokines. RESULTS: The TW group exhibited a decrease of reduced glutathione in their jejunum, which was prevented in the L-glutathione treated TWGT group. TW animals presented pronounced oxidative stress by increasing levels of lipoperoxidation in their jejunum and malondialdehyde in their plasma; however, the L-glutathione treatment in TWGT group was not able to avoid it. The total antioxidant capacity was altered in groups TW and TWGT, yet the last one had a better index in their plasma. The IL-10, and TNF-α levels increased in TWGT animals. The nNOS-IR neuron density decreased in the jejunum myenteric plexus of the TW group, which was avoided in the TWGT group. The nNOS +3-Nitrotyrosine neurons quantification did not show significative alterations. CONCLUSION: The treatment with L-glutathione (1%) imposed an important defense to some parameters of oxidative stress induced by TW-256, leading to neuroprotection to the loss in the nNOS-IR neuron density.

Resistance Training Attenuates Activation of STAT3 and Muscle Atrophy in Tumor-Bearing Mice.

Purpose: Although the role of signal transducers and activators of transcription (STAT3) in cachexia due to the association of circulating IL-6 and muscle wasting has been extensively demonstrated, the effect of resistance training on STAT3 in mediating muscle atrophy in tumor-bearing mice is unknown. The aim of this study is to investigate the effects of resistance exercise training on inflammatory cytokines and oxidative-mediated STAT3 activation and muscle loss prevention in tumor-bearing mice. Methods: Male Swiss mice were inoculated with Ehrlich tumor cells and exposed or not exposed to resistance exercise protocol of ladder climbing. Skeletal muscle STAT3 protein content was measured, compared between groups, and tested for possible association with plasma interleukins and local oxidative stress markers. Components of the ubiquitin-proteasome and autophagy pathways were assessed by real-time PCR or immunoblotting. Results: Resistance training prevented STAT3 excessive activation in skeletal muscle mediated by the overabundance of plasma IL-6 and muscle oxidative stress. These mechanisms contributed to preventing the increased key genes and proteins of ubiquitin-proteasome and autophagy pathways in tumor-bearing mice, such as Atrogin-1, LC3B-II, and Beclin-1. Beyond preventing muscle atrophy, RT also prevented strength loss and impaired locomotor capacity, hallmarks of sarcopenia. Conclusion: Our results suggest that STAT3 inhibition is central in resistance exercise protective effects against cancer-induced muscle atrophy and strength loss.

Sulfasalazine exposure during pregnancy and lactation induces alterations in reproductive behavior in adult female rat offspring.

AIMS: Sulfasalazine (SAS) is the first line drug in the treatment of chronic inflammatory bowel diseases in pregnant women. SAS and its metabolites cross the placenta and can be transferred through the milk. However, the long-term consequences to the reproductive system of offspring from dams exposed to SAS have not yet been studied. Thus, our study investigated the effects of SAS treatment during gestational and lactational periods on maternal care in F0 and reproductive outcomes in F1 females. MAIN METHODS: Wistar female rats (n = 10/group) received 300 mg/kg/day of SAS dissolved in carboxymethyl cellulose (CMC), by gavage, from gestational day 0 to lactation day 21 and 3 mg/kg/day of folic acid during gestation. The control group received CMC only. On PND 21, the female pups were selected for reproductive evaluation at different time points: infancy and adulthood. The reproductive parameters evaluated were installation of puberty (vaginal opening and first estrus), estrous cyclicity, reproductive organs weight, histological analysis of the ovary follicles and uterus, analysis of oxidative stress in ovarian tissue, reproductive behavior (sexual and maternal), and fertility. KEY FINDINGS: SAS treatment decreased the retrieving behavior in F0 females. The F1 females presented an increase in the lordosis score, frequency of lordosis of magnitude 3, and lipid peroxidation of ovarian tissues in both infancy and adult life. SIGNIFICANCE: The SAS effects observed in the current study represent a relevant concern for public health, as they demonstrated that treatment with SAS compromised the maternal motivation of dams and induced reproductive alterations in F1 females.

Protective effects of quercetin-loaded microcapsules on the enteric nervous system of diabetic rats.

Quercetin-loaded microcapsules (QLM) promote controlled release and higher bioavailability of quercetin, an antioxidant and neuroprotective agent. We evaluated the antioxidant effect of QLM on enteric innervation and in the oxidative status of the ileum of diabetic rats. Wistar adult rats (Rattus norvegicus) were used in six groups containing normoglycemic (N), diabetic (D) and either normoglycemic or diabetic groups treated with QLM at a dose of 10 mg/kg (NQ10 and DQ10, respectively) or 100 mg/kg (NQ100 and DQ100, respectively). DQ10 e DQ100 did not prevent overall neuronal loss in the total and cholinergic populations. Nitrergic population showed differences regarding the treatments: DQ10 preserved neurons in the nitrergic population whilst DQ100 increased nitrergic loss. Evaluation of the redox status showed pro-oxidant effects in NQ100 by t-butyl-induced chemiluminescence analysis. We observed a reduction in the carbonylic content and an increase of low molecular weight antioxidants for DQ10 e DQ100. Therefore, QLM treatment at a dose of 10 mg/kg acted positively on nitrergic neurons reducing oxidative damage induced by diabetes.

Pulmonary Emphysema Impairs Male Reproductive Physiology Due To Testosterone and Oxidative Stress Imbalance in Mesocricetus auratus.

This study evaluated whether pulmonary emphysema affects sperm quality, male reproductive organs, and testosterone levels in adult male hamsters. Mesocricetus auratus males (130-150 g) were subdivided into a control group (C group) and an emphysema group (E group). The C group received an intratracheal instillation of saline solution (0.3 mL/100 g of body weight), and the E group received papain (40 mg/100 g of body weight). After 60 days, the biometric, pulmonary, and reproductive parameters of each group were evaluated. The E group developed pulmonary emphysema, which decreased body weight and sperm quality compared to the C group. In oxidative stress-related assays, lipid peroxidation was increased in the testis and epididymis (caput and cauda) in the E group compared with the C group. However, only the caput epididymis showed a reduction in glutathione levels. Pulmonary emphysema also affected the testicle by inducing an increase in abnormal seminiferous tubules, accompanied by a decrease in seminiferous epithelium height. Spermatogenesis kinetics were also modified by pulmonary emphysema. The number of Leydig and Sertoli cells decreased in the E group, accompanied by an increase in the nuclear volume of Leydig cells. Testosterone concentration was increased in the E group. Similarly, pulmonary emphysema altered epididymal components in all regions. In conclusion, pulmonary emphysema affected the reproductive system in this experimental model, as shown by testicular and epididymal morphophysiology changes, hormonal alteration, and oxidative stress imbalance, inducing the loss of correct function in the male reproductive system.

Exposure to low doses of malathion during juvenile and peripubertal periods impairs testicular and sperm parameters in rats: Role of oxidative stress and testosterone.

Malathion is an organophosphate insecticide used in agriculture and for controlling vector-borne diseases such as Zika. Humans can be exposed to malathion by means of ingestion of contaminated food. The juvenile and peripubertal periods are a large window of vulnerability to the action of toxic agents. The aim of the present study was to evaluate the effects of low doses of malathion during the development of testes in the juvenile and peripubertal periods in rats. For this purpose, 45 male Wistar rats (postnatal day (PND) 25) were assigned to 3 experimental groups and treated for 40 days. The animals were exposed daily to malathion 10 mg/kg (M10 group) or 50 mg/kg (M50 group) diluted in 0.9 % saline via gavage. The control group received only the vehicle. On the 40th experimental day, the rats were anaesthetized and euthanized. The blood was collected for determination of testosterone concentration. The testes were removed and weighed. Spermatozoa from the vas deferens were used for sperm morphological analysis. The testes were used for evaluation of sperm count and oxidative stress status to determine the inflammatory profile and analysis of tissue constitution. The results showed that both malathion doses reduced the sperm count and increased the number of abnormal sperms. Furthermore, both doses altered the spermatogenetic process, delayed spermiogenesis, reduced the Leydig and Sertoli cell number and increased the thickness of tunica albuginea. The M10 group presented increased IL-10 levels and reduced GSH levels. These parameters did not change in the M50 group. However, the M50 group showed an increase in the number of abnormal seminiferous tubules, a decrease in plasma testosterone concentration and an increase in lipid peroxidation in the testes. In conclusion, the exposure to low doses of malathion during juvenile and peripubertal development resulted in testicular toxicity and compromised the testicular morphology and function.

Quercetin increases bioavailability of nitric oxide in the jejunum of euglycemic and diabetic rats and induces neuronal plasticity in the myenteric plexus.

Considering the antioxidant, neuroprotective, inflammatory and nitric oxide modulatory actions of quercetin, the aim of this study was to test the effect of quercetin administration in drinking water (40 mg/day/rat) on neuronal nitric oxide synthase (nNOS), vasoactive intestinal peptide (VIP), overall population of myenteric neurons (HuC/D) and nitric oxide (NO) levels in the jejunal samples from diabetic rats. Male Wistar rats were distributed into four groups (8 rats per group): euglycemic (E), euglycemic administered with quercetin (E+Q), diabetic (D) and diabetic administered with quercetin (D+Q). Rats were induced to diabetes with streptozotocin (35mg/kg/iv) and, after 120 days, the proximal jejunum were collected and processed for immunohistochemical (VIP, nNOS and HuC/D) and chemiluminescence (quantification of tissue NO levels) techniques. Diabetes mellitus reduced the number of nNOS-IR (immunoreactive) (p <0.05) and HuC/D-IR (p <0.001) neurons, however, promoted an increased morphometric area of nNOS-IR neurons (p <0.001) and VIP-IR varicosities (p <0.05). In D+Q group, neuroplasticity effects were observed on HuC/D-IR neurons, accompanied by a reduction of cell body area of neurons nNOS- and VIP-IR varicosities (p <0.05). The NO levels were increased in the E+Q (p <0.05) and D+Q group (p <0.001) compared to the control group. In conclusion, the results showed that quercetin supplementation increased the bioavailability of NO in the jejunum in euglycemic and mitigate the effects of diabetes on nNOS-IR neurons and VIP-IR varicosities in the myenteric plexus of diabetic rats.

Muscle changes with high-intensity aerobic training in an animal model of renal disease.

PURPOSE: To analyze the muscle changes with high-intensity aerobic training (HIAT) in an animal model of renal disease (RD). METHODS: Twenty one adult Wistar rats were divided into 3 groups: healthy sedentary (HS), RD sedentary (RDS), RD aerobic training (RDAT). RDS and RDAT were subjected to unilateral renal ischemia-reperfusion (10 min) and 21days after that, RDAT was subjected to 6 weeks HIAT (swimming). Serum creatinine (Cr) and muscle morphometry (cross-sectional area = CSA) of gastrocnemius were analyzed. RESULTS: Cr was higher (p = 0.0053) in RDS (0.82 ± 0.04) than in the others (RDAT 0.55 ± 0.04; HS 0.55 ± 0.04). Morphometric analysis (class interval of CSA in µm2/absolute frequency of muscle fibers in each class) indicated that 50th percentile occurred in: HS 7th class (3000.00-3499.00/515), RDS, 8th class (3500.00-3999.00/484), RDAT 5th class (2000.00-2499.00/856). CSA of largest fibers in RDS, RDAT, HS was 9953.00 µm2, 9969.00 µm2,11228.00 µm2, respectively. High frequency of fibers with lower CSA occurred in 4th, 5th, 6th and 7th class in RDA, absence of fibers into 22nd, 23rd classes (RDS and RDAT). CONCLUSION: HIAT in an animal model of RD resulted in increased the number of muscle fibers with smaller CSA.

Muscle changes with high-intensity aerobic training in an animal model of renal disease

Abstract Purpose: To analyze the muscle changes with high-intensity aerobic training (HIAT) in an animal model of renal disease (RD). Methods: Twenty one adult Wistar rats were divided into 3 groups: healthy sedentary (HS), RD sedentary (RDS), RD aerobic training (RDAT). RDS and RDAT were subjected to unilateral renal ischemia-reperfusion (10 min) and 21days after that, RDAT was subjected to 6 weeks HIAT (swimming). Serum creatinine (Cr) and muscle morphometry (cross-sectional area = CSA) of gastrocnemius were analyzed. Results: Cr was higher (p = 0.0053) in RDS (0.82 ± 0.04) than in the others (RDAT 0.55 ± 0.04; HS 0.55 ± 0.04). Morphometric analysis (class interval of CSA in μm2/absolute frequency of muscle fibers in each class) indicated that 50th percentile occurred in: HS 7th class (3000.00-3499.00/515), RDS, 8th class (3500.00-3999.00/484), RDAT 5th class (2000.00-2499.00/856). CSA of largest fibers in RDS, RDAT, HS was 9953.00 μm2, 9969.00 μm2,11228.00 μm2, respectively. High frequency of fibers with lower CSA occurred in 4th, 5th, 6th and 7th class in RDA, absence of fibers into 22nd, 23rd classes (RDS and RDAT). Conclusion: HIAT in an animal model of RD resulted in increased the number of muscle fibers with smaller CSA.

Aerobic Training Prevents Heatstrokes in Calsequestrin-1 Knockout Mice by Reducing Oxidative Stress.

Calsequestrin-1 knockout (CASQ1-null) mice suffer lethal episodes when exposed to strenuous exercise and environmental heat, crises known as exertional/environmental heatstroke (EHS). We previously demonstrated that administration of exogenous antioxidants (N-acetylcysteine and trolox) reduces CASQ1-null mortality during exposure to heat. As aerobic training is known to boost endogenous antioxidant protection, we subjected CASQ1-null mice to treadmill running for 2 months at 60% of their maximal speed for 1 h, 5 times/week. When exposed to heat stress protocol (41°C/1 h), the mortality rate of CASQ1-null mice was significantly reduced compared to untrained animals (86% versus 16%). Protection from heatstrokes was accompanied by a reduced increase in core temperature during the stress protocol and by an increased threshold of response to caffeine of isolated extensor digitorum longus muscles during in vitro contracture test. At cellular and molecular levels, aerobic training (i) improved mitochondrial function while reducing their damage and (ii) lowered calpain activity and lipid peroxidation in membranes isolated from sarcoplasmic reticulum and mitochondria. Based on this evidence, we hypothesize that the protective effect of aerobic training is essentially mediated by a reduction in oxidative stress during exposure of CASQ1-null mice to adverse environmental conditions.

Supplementation with l-glutathione improves oxidative status and reduces protein nitration in myenteric neurons in the jejunum in diabetic Rattus norvegicus.

Diabetes mellitus is a syndrome with multiple etiologies, characterized by chronic hyperglycemia that increases the production of reactive oxygen species and decreases antioxidant defenses. The present study evaluated oxidative stress parameters and protein nitration in myenteric neurons in the jejunum in diabetic rats supplemented with l-glutathione. Rats (90 days of age) were distributed into four groups (n = 6/group): normoglycemic (N), normoglycemic supplemented with l-glutathione (NGT), diabetic (D), and diabetic supplemented with l-glutathione (DGT). At 210 days of age, the animals were sacrificed, and the jejunum was collected, washed, and subjected to various procedures: tert-butyl hydroperoxide chemiluminescence (CL), determination of total antioxidant capacity (TAC), determination of catalase activity, quantification of nitric oxide (NO), and double-labeling of HuC/D-immunoreactive myenteric neurons and nitrotyrosine (3-NT). Diabetes increased oxidative stress in the jejunum in the D group, reflected by increases in lipid peroxidation, TAC, catalase activity, and NO. The D group exhibited an increase in the percentage of myenteric neurons that were double-labeled with 3-NT. Supplementation with l-glutathione did not cause differences in the average CL curves between the D and DGT groups, but reductions of TAC and catalase activity were observed. Supplementation with l-glutathione promoted a reduction of neurons that contained 3-NT in the DGT group. Diabetes mellitus promoted oxidative stress in the jejunum, and supplementation with l-glutathione improved oxidative status by preventing protein nitration in myenteric neurons in diabetic animals that received supplementation.

Does l-glutamine-supplemented diet extenuate NO-mediated damage on myenteric plexus of Walker 256 tumor-bearing rats?

This study was designed to appraise the relationship between enteric neuropathy and oxidative stress in cancer cachexia under l-glutamine-supplemented diet. Total and nitrergic neuronal populations were investigated in jejunum and ileum in four experimental groups: control (C); control l-glutamine-supplemented diet (CG); Walker-256 tumor (TW); and Walker-256 tumor supplemented with l-glutamine (TWG). In addition, local oxidative stress, neuronal nitric oxide synthase (nNOS) enzyme and nitric oxide (NO) levels were evaluated. Neuronal density and somatic area of the total and nitrergic populations were reduced in TW rats, which was accompanied by high oxidative stress, NO and nNOS levels. l-glutamine supplementation prevented neuronal atrophy, changes in pan neuronal density and nNOS overexpression (ileum), and restored total antioxidant capacity. Nevertheless, the oxidative stress was partially mitigated and no effect was observed on the reduction of nitrergic population and NO levels. l-glutamine-supplemented diet extenuates NO-mediated damage on the myenteric plexus although has a small benefit on oxidative stress.

Resistance exercise attenuates skeletal muscle oxidative stress, systemic pro-inflammatory state, and cachexia in Walker-256 tumor-bearing rats.

The aim of this study was to investigate the effects of resistance exercise training (RET) on oxidative stress, systemic inflammatory markers, and muscle wasting in Walker-256 tumor-bearing rats. Male (Wistar) rats were divided into 4 groups: sedentary controls (n = 9), tumor-bearing (n = 9), exercised (n = 9), and tumor-bearing exercised (n = 10). Exercised and tumor-bearing exercised rats were exposed to resistance exercise of climbing a ladder apparatus with weights tied to their tails for 6 weeks. The physical activity of control and tumor-bearing rats was confined to the space of the cage. After this period, tumor-bearing and tumor-bearing exercised animals were inoculated subcutaneously with Walker-256 tumor cells (11.0 × 107 cells in 0.5 mL of phosphate-buffered saline) while control and exercised rats were injected with vehicle. Following inoculation, rats maintained resistance exercise training (exercised and tumor-bearing exercised) or sedentary behavior (control and tumor-bearing) for 12 more days, after which they were euthanized. Results showed muscle wasting in the tumor-bearing group, with body weight loss, increased systemic leukocytes, and inflammatory interleukins as well as muscular oxidative stress and reduced mTOR signaling. In contrast, RET in the tumor-bearing exercised group was able to mitigate the reduced body weight and muscle wasting with the attenuation of muscle oxidative stress and systemic inflammatory markers. RET also prevented loss of muscle strength associated with tumor development. RET, however, did not prevent the muscle proteolysis signaling via FBXO32 gene messenger RNA expression in the tumor-bearing group. In conclusion, RET performed prior tumor implantation prevents cachexia development by attenuating tumor-induced systemic pro-inflammatory condition with muscle oxidative stress and muscle damage.

l-Glutamine supplementation promotes an improved energetic balance in Walker-256 tumor-bearing rats.

We evaluated the effects of supplementation with oral l-glutamine in Walker-256 tumor-bearing rats. A total of 32 male Wistar rats aged 54 days were randomly divided into four groups: rats without Walker-256 tumor, that is, control rats (C group); control rats supplemented with l-glutamine (CG group); Walker-256 tumor rats without l-glutamine supplementation (WT group); and WT rats supplemented with l-glutamine (WTG group). l-Glutamine was incorporated into standard food at a proportion of 2 g/100 g (2%). After 10 days of the experimental period, the jejunum and duodenum were removed and processed. Protein expression levels of key enzymes of gluconeogenesis, that is, phosphoenolpyruvate carboxykinase and glucose-6-phosphatase, were analyzed by western blot and immunohistochemical techniques. In addition, plasma corticosterone, glucose, insulin, and urea levels were evaluated. The WTG group showed significantly increased plasma glucose and insulin levels ( p < 0.05); however, plasma corticosterone and urea remained unchanged. Moreover, the WTG group showed increased immunoreactive staining for jejunal phosphoenolpyruvate carboxykinase and increased expression of duodenal glucose-6-phosphatase. Furthermore, the WTG group presented with less intense cancer cachexia and slower tumor growth. These results could be attributed, at least partly, to increased intestinal gluconeogenesis and insulinemia, and better glycemia maintenance during fasting in Walker-256 tumor rats on a diet supplemented with l-glutamine.

Supplementation with L-glutamine prevents tumor growth and cancer-induced cachexia as well as restores cell proliferation of intestinal mucosa of Walker-256 tumor-bearing rats.

This study aimed to evaluate the intestinal mucosa of the duodenum and jejunum of Walker-256 tumor-bearing rats supplemented with L-glutamine. Thirty-two male 50-day-old Wistar rats (Rattus norvegicus) were randomly divided into four groups: control (C), control supplemented with 2 % L-glutamine (GC), Walker-256 tumor (WT), and Walker-256 tumor supplemented with 2 % L-glutamine (TWG). Walker-256 tumor was induced by inoculation viable tumor cells in the right rear flank. After 10 days, celiotomy was performed and duodenal and jejunal tissues were removed and processed. We evaluated the cachexia index, proliferation index, villus height, crypt depth, total height of the intestinal wall, and number of goblet cells by the technique of periodic acid-Schiff (PAS). Induction of Walker-256 tumor promoted a reduction of metaphase index in the TW group animals, which was accompanied by a reduction in the villous height and crypt depths, resulting in atrophy of the intestinal wall as well as increased PAS-positive goblet cells. Supplementation with L-glutamine reduced the tumor growth and inhibited the development of the cachectic syndrome in animals of the TWG group. Furthermore, amino acid supplementation promoted beneficial effects on the intestinal mucosa in the TWG animals through restoration of the number of PAS-positive goblet cells. Therefore, supplementation with 2 % L-glutamine exhibited a promising role in the prevention of tumor growth and cancer-associated cachexia as well as restoring the intestinal mucosa in the duodenum and jejunum of Walker-256 tumor-bearing rats.

Solid Ehrlich carcinoma reproduces functional and biological characteristics of cancer cachexia.

AIMS: Well-characterized animal tumor models of cancer cachexia are warranted to elucidate underlying mechanisms and provide a better approach to the human scenario. We aimed to investigate whether solid Ehrlich carcinoma reproduces clinical, functional and biological conditions of tumor-induced cachexia in mice. METHODS: Eight-week old female Swiss mice were subcutaneously inoculated with Ehrlich tumor cells (tumor-bearing, TB group) or vehicle (sham) into the right flank and monitored for 28days. Tumor histopathological features and tumor-host interaction, including tissue weight, muscle structure, strength and biochemical parameters were carried out. KEY FINDINGS: Tumor growth curve demonstrated a linear pattern with no difference in final carcass weight between groups. A well-defined capsule composed by connective tissue infiltrated by inflammatory and neoplastic cells surrounded the tumors. The TB group had reduced handgrip strength, aside from lower cross sectional area (CSA) and critically reduced parametrial fat pads. Plasma parameters of lactate dehydrogenase (LDH), creatine kinase (CK) and tumor necrosis factor-α (TNF-α) were higher in the TB group, suggesting predominance of catabolic and pro-inflammatory activities. Conversely, food intake and tissue weight did not differ between groups. SIGNIFICANCE: Our data elucidated that the solid Ehrlich tumor model is feasible and effective in reproducing some of the relevant issues experienced by cancer patients with cachexia. The solid Ehrlich carcinoma emerges as an alternative tool against more aggressive cancer cachexia models during preclinical research.

Resistance exercise prevents impaired homocysteine metabolism and hepatic redox capacity in Walker-256 tumor-bearing male Wistar rats.

OBJECTIVE: The aim of this study was to investigate changes in homocysteine (Hcy) metabolism and redox balance in response to exercise treatment in a tumor-bearing rat model. METHODS: Male Wistar rats were exposed, or not, to a resistance exercise program 6 wk before inoculation with Walker-256 tumor cells or vehicle. After application, rats maintained their routine for 12 d and were then sacrificed for plasma and liver analyses. RESULTS: Impaired Hcy metabolism was evident after 12 d of tumor cell inoculation as demonstrated by significantly increased (P < 0.05) plasma total homocysteine (tHcy) concentration (53%) and decreased plasma cysteine, methionine, and vitamin B12 concentrations. Decreased hepatic cystathionine ß-synthase (CBS) and betaine-homocysteine S-methyltransferase mRNA levels were found in tumor-bearing rats but not in controls. Tumor inoculation also decreased levels of liver reduced glutathione (GSH) and increased hepatic oxidative stress compared with non-tumor controls. However, resistance exercise prevented the tumor-impaired transsulfuration pathway as demonstrated by the decreased plasma tHcy, hepatic CBS expression, and increased GSH in tumor-exercised versus tumor-sedentary rats. Remarkably, all measures of liver oxidative stress were suppressed by exercise training. Tumor weight was unchanged between groups. CONCLUSION: Resistance exercise prevented tHcy accumulation and liver oxidative damage caused by Walker-256 tumor cell inoculation; the modulatory effects of resistance exercise on Hcy metabolism appear to be at the level of transsulfuration pathway.

Correlation of TGF-ß1 and oxidative stress in the blood of patients with melanoma: a clue to understanding melanoma progression?

TGF-ß1 and oxidative stress are involved in cancer progression, but in melanoma, their role is still controversial. Our aim was to correlate plasma TGF-ß1 levels and systemic oxidative stress biomarkers in patients with melanoma, with or without disease metastasis, to understand their participation in melanoma progression. Thirty patients were recruited for melanoma surveillance, together with 30 healthy volunteers. Patients were divided into two groups: Non-metastasis, comprising patients with tumor removal and no metastatic episode for 3 years; and Metastasis, comprising patients with a metastatic episode. The plasmatic cytokines TGF-ß1, IL-1 ß, and TNF-α were analyzed by ELISA. For oxidative stress, the following assays were performed: malondialdehyde (MDA), advanced oxidation protein products (AOPP) levels, total radical-trapping antioxidant parameter (TRAP) and thiol in plasma, and lipid peroxidation, SOD and catalase activity and GSH in erythrocytes. Patients with a metastatic episode had less circulating TGF-ß1 and increased TRAP, thiol, AOPP and lipid peroxidation levels. MDA was increased in both melanoma groups, while catalase, GSH, and IL-1ß was decreased in Non-metastasis patients. Significant negative correlations were observed between TGF-ß1 levels and systemic MDA, and TGF-ß1 levels and systemic AOPP, while a positive correlation was observed between TGF-ß1 levels and erythrocyte GSH. Lower levels of TGF-ß1 were related to increased oxidative stress in Metastasis patients, reinforcing new evidence that in melanoma TGF-ß1 acts as a tumor suppressor, inhibiting tumor relapse. These findings provide new knowledge concerning this cancer pathophysiology, extending the possibilities of investigating new therapies based on this evidence.