Amanda Leite Bastos-Pereira

Antitumoral and antioxidant effects of a hydroalcoholic extract of cat's claw (Uncaria tomentosa) (Willd. Ex Roem. & Schult) in an in vivo carcinosarcoma model.

AIM OF THE STUDY The present work intended to study the antitumoral and antioxidant effects of Uncaria tomentosa (UT) hydroalcoholic extract in the Walker-256 cancer model. METHODS AND MATERIALS Walker-256 cells were subcutaneously inoculated in the pelvic limb of male Wistar rats. Daily gavage with UT extract (10, 50 or 100 mg kg(-1), Groups UT) or saline solution (Control, Group C) was subsequently initiated, until 14 days afterwards. For some parameters, a group of healthy rats (Baseline, Group B) was added. At the end of treatment the following parameters were evaluated: (a) tumor volume and mass; (b) plasmatic concentration of urea, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT) and lactate dehydrogenase (LDH); (c) hepatic and tumoral activity of catalase (CAT) and superoxide dismutase (SOD), as well as the rate of lipid peroxidation (LPO) and gluthatione (GSH); and (d) hepatic glutathione-S-transferase (GST) activity. The reactivity of UT extract with the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) was assessed in parallel. RESULTS UT hydroalcoholic extract successfully reduced the tumor growth. In addition, treatment with UT reduced the activity of AST, which had been increased as a result of tumor inoculation, thus attempting to return it to normal levels. UT did not reverse the increase of LDH and GGT plasma levels, although all doses were remarkably effective in reducing urea plasma levels. An important in vitro free radical-scavenging activity was detected at various concentrations of UT extract (1-300 microg mL(-1)). Treatment also resulted in increased CAT activity in liver, while decreasing it in tumor tissue. SOD activity was reduced in liver as well as in tumor, compared to Group C. No statistical significance concerning ALT, GST, LPO or GSH were observed. CONCLUSIONS This data represent an in vivo demonstration of both antitumoral and antioxidant effects of UT hydroalcoholic extract. The antineoplastic activity may result, partially at least, from the ability of UT to regulate redox and metabolism homeostasis.

The FXR agonist 6ECDCA reduces hepatic steatosis and oxidative stress induced by ethanol and low-protein diet in mice

BACKGROUND AND AIM Excessive ethanol consumption can lead to development of hepatic steatosis. Since the FXR receptor regulates adipose cell function and liver lipid metabolism, the aim of this work was to examine the effects of the FXR agonist 6ECDCA on alcoholic liver steatosis development and on oxidative stress induced by ethanol consumption. METHODS Swiss mice (n=24) received a low-protein diet (6%) and a liquid diet containing 10% ethanol or water for 6weeks. In the last 15days mice received oral treatment with 6ECDCA (3mgkg(-1)) or 1% tween (vehicle). The experimental groups (n=6) were: water+tween, water+6ECDCA, ethanol+tween and ethanol+6ECDCA. Moreover, as a diet control, we used a basal group (n=6), fed by a normal-proteic diet (23%) and water. After the treatment period, the animals were anesthetized for sample collection to perform plasma biochemistry assays, hepatic oxidative stress assays, hepatic cholesterol and triglycerides measurements, liver histology and hepatic gene expression. RESULTS Ethanol associated with low-protein diet induced hepatic oxidative stress, increased plasma transaminases and induced hepatic lipid accumulation. Many of these parameters were reversed by the administration of 6ECDCA, including amelioration of lipid accumulation and lipoperoxidation, and reduction of reactive oxygen species. These effects were possibly mediated by regulation of Srebpf1 and FAS gene expression, both reduced by the FXR agonist. CONCLUSIONS Our data demonstrated that 6ECDCA reverses the accumulation of lipids in the liver and decreases the oxidative stress induced by ethanol and low-protein diet. This FXR agonist is promising as a potential therapy for alcoholic liver steatosis.

Uncaria tomentosa Exerts Extensive Anti-Neoplastic Effects against the Walker-256 Tumour by Modulating Oxidative Stress and Not by Alkaloid Activity

This study aimed to compare the anti-neoplastic effects of an Uncaria tomentosa (UT) brute hydroethanolic (BHE) extract with those of two fractions derived from it. These fractions are choroformic (CHCl3) and n-butanolic (BuOH), rich in pentacyclic oxindole alkaloids (POA) and antioxidant substances, respectively. The cancer model was the subcutaneous inoculation of Walker-256 tumour cells in the pelvic limb of male Wistar rat. Subsequently to the inoculation, gavage with BHE extract (50 mg.kg−1) or its fractions (as per the yield of the fractioning process) or vehicle (Control) was performed during 14 days. Baseline values, corresponding to individuals without tumour or treatment with UT, were also included. After treatment, tumour volume and mass, plasma biochemistry, oxidative stress in liver and tumour, TNF-α level in liver and tumour homogenates, and survival rates were analysed. Both the BHE extract and its BuOH fraction successfully reduced tumour weight and volume, and modulated anti-oxidant systems. The hepatic TNF-α level indicated a greater effect from the BHE extract as compared to its BuOH fraction. Importantly, both the BHE extract and its BuOH fraction increased the survival time of the tumour-bearing animals. Inversely, the CHCl3 fraction was ineffective. These data represent an in vivo demonstration of the importance of the modulation of oxidative stress as part of the anti-neoplastic activity of UT, as well as constitute evidence of the lack of activity of isolated POAs in the primary tumour of this tumour lineage. These effects are possibly resulting from a synergic combination of substances, most of them with antioxidant properties.

Involvement of brain cytokines in zymosan-induced febrile response

This study compared the involvement of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) within the central nervous system (CNS) in the febrile response induced by zymosan (zym) and lipopolysaccharide (LPS). In addition, we investigated whether zym could activate important regions related to fever; namely, the vascular organ of the laminae terminalis (OVLT) and the median preoptic nucleus (MnPO). Intraperitoneal injection of zym (1, 3, and 10 mg/kg) induced a dose-related increase in core temperature. Zym (3 mg/kg) also reduced tail skin temperature, suggesting the activation of heat conservation mechanisms, as expected, during fever. LPS increased plasma levels of TNF-α measured at 1 h, IL-1β measured at 2 h, and IL-6 measured at 3 h after injection. Zym increased circulating levels of IL-6 but not those of TNF-α or IL-1β at the same time points. In addition, an intracerebroventricular injection of antibodies against TNF-α (2.5 μg) and IL-6 (10 μg) or the IL-1 receptor antagonist (160 ng) reduced the febrile response induced by zym and LPS. Zym (100 μg/ml) also increased intracellular calcium concentration in the OVLT and MnPO from rat primary neuroglial cultures and increased release of TNF-α and IL-6 into the supernatants of these cultures. Together, these results suggest that TNF-α, IL-1β, and IL-6 within the CNS participate in the febrile response induced by zym. However, the time course of release of these cytokines may be different from that of LPS. In addition, zym can directly activate the brain areas related to fever.

Etanercept reduces thermal and mechanical orofacial hyperalgesia following inflammation and neuropathic injury

This study evaluated the involvement of tumour necrosis factor α (TNF‐α) in orofacial thermal and mechanical hyperalgesia induced by an inflammatory stimulus or by chronic constriction of the infraorbital nerve (CION) using etanercept (Eta), a TNF‐receptor fusion protein that inhibits TNF‐α action.

Antinociceptive activity of the ethanolic extract, fractions, and aggregatin D isolated from Sinningia aggregata tubers.

The present study investigated the effects of the ethanolic extract (ESa), fractions, and compounds isolated from Sinningia aggregata in male Swiss mice on carrageenan-induced paw edema, neutrophil migration, mechanical hyperalgesia, formalin-induced nociception, and lipopolysaccharide-induced fever. The ESa did not alter edema, neutrophil migration, or fever at any of the doses tested. However, the ESa reduced phase II of formalin-induced nociception and carrageenan-induced mechanical hyperalgesia. The petroleum ether (PE) and ethyl acetate (EA) fractions and aggregatin D (AgD; isolated from the EA fraction) reduced formalin-induced nociception. Anthraquinones from the PE fraction were ineffective. AgD also inhibited carrageenan-induced mechanical hyperalgesia. Neither the ESa nor AgD altered thermal nociception or motor performance. Local administration of AgD also reduced hyperalgesia induced by carrageenan, bradykinin, tumor necrosis factor-α, interleukin-1β, cytokine-induced neutrophil chemoattractant, prostaglandin E2, and dopamine but not hyperalgesia induced by forskolin or dibutyryl cyclic adenosine monophosphate. The positive control dipyrone reduced the response induced by all of the stimuli. Additionally, glibenclamide abolished the analgesic effect of dipyrone but not the one induced by AgD. AgD did not change lipopolysaccharide-induced nitric oxide production by macrophages or the nociception induced by capsaicin, cinnamaldehyde, acidified saline, or menthol. These results suggest that the ESa has important antinociceptive activity, and this activity results at least partially from the presence of AgD. AgD reduced mechanical hyperalgesia induced by several inflammatory mediators through mechanisms that are different from classic analgesic drugs.

Central mediators involved in the febrile response induced by polyinosinic-polycytidylic acid: Lack of involvement of endothelins and substance P

The present study evaluated the involvement of interleukin(IL)-1β, tumor necrosis factor-α (TNF-α), IL-6, interferon(IFN)-γ, prostaglandins of the E2 series, endothelins, substance P and opioids within the central nervous system in polyinosinic:polycytidylic acid (Poly I:C)-induced fever in rats. Poly I:C injection induced a febrile response which was reduced by intracerebroventricular administration of the antibodies against TNF-α, IL-6, or IFN-γ, or by IL-1 or μ receptor antagonists. Intraperitoneal injection of indomethacin or oral administration of celecoxib also reduced Poly I:C-induced fever. Poly I:C increased prostaglandin E2 levels in the cerebrospinal fluid of the animals which was also reduced by indomethacin. The intracerebroventricular injection of ETB or NK1 receptor antagonists did not alter Poly I:C-induced fever. These data suggest the involvement of IL-1β, TNF-α, IL-6, IFN-γ, prostaglandin E2, and opioids but not endothelins and substance P on Poly I:C-induced fever.

Effects of statins on liver cell function and inflammation in septic rats.

BACKGROUND Several studies suggest that the presence of statins may be beneficial during sepsis, but this idea is controversial. The aim of this study was to investigate the effects of long-term statin treatment in the livers of septic animals, focusing on its antioxidant, antiinflammatory, and metabolic properties. MATERIALS AND METHODS Male Wistar rats were treated orally with simvastatin, atorvastatin, or vehicle once a d. After 30 d, sepsis was induced by cecal ligation and puncture (CLP) in Control, Simvastatin-treated, and Atorvastatin-treated groups, while the Sham group underwent only laparotomy. The Basal Simvastatin and Basal Atorvastatin groups received only their respective drugs without surgery. Twenty-four h after CLP or laparotomy, samples were collected from anesthetized rats for evaluation of hepatic oxidative stress, liver histology, hepatic mitochondria enzyme activity, leukocyte counts in blood and peritoneal cavity, gene expression of hepatic superoxide dismutase and TNF-2, and plasma biochemistry. RESULTS Most parameters that we tested exhibited expected changes upon sepsis induction. However, statin treatment only improved liver mitochondrial enzymatic activity. In other parameters, simvastatin and atorvastatin failed to protect the liver against injuries incurred upon the CLP-induced polymicrobial sepsis model. CONCLUSIONS Pretreatment with simvastatin or atorvastatin alone before sepsis induction improved mitochondrial activity in the liver; however, this result was not reproduced in other biomarkers of liver function and leukocyte migration during sepsis. Future studies should be performed to evaluate whether statins can be combined with other drugs to increase the efficacy of sepsis therapy.

Involvement of Central Endothelin ETA and Cannabinoid CB1 Receptors and Arginine Vasopressin Release in Sepsis Induced by Cecal Ligation and Puncture in Rats.

ABSTRACT We previously reported that endothelin-1 (ET-1) reduced the frequency of spontaneous excitatory currents in vasopressinergic magnocellular cells through the activation of endothelin ETA receptors in rat brain slices. This effect was abolished by a cannabinoid CB1 receptor antagonist, suggesting the involvement of endocannabinoids. The present study investigated whether the blockade of ETA or CB1 receptors during the phase of increased levels of ET-1 after severe sepsis increases the survival rate of animals concomitantly with an increase in plasma arginine vasopressin (AVP) levels. Sepsis was induced in male Wistar rats by cecal ligation and puncture (CLP). Treatment with the CB1 receptor antagonist rimonabant (Rim; 10 and 20 mg/kg, orally) 4 h after CLP (three punctures) significantly increased the survival rate compared with the CLP per vehicle group. Intracerebroventricular treatment with the ETA receptor antagonist BQ123 (100 pmol) or with Rim (2 &mgr;g) 4 and 8 h after CLP but not the ETB receptor antagonist BQ788 (100 pmol), also significantly improved the survival rate. Sham-operated and CLP animals that were treated with Rim had significantly lower core temperature than CLP animals. However, oral treatment with Rim did not change bacterial count in the peritoneal exudate, neutrophil migration to the peritoneal cavity, leucopenia or increased plasma interleukin-6 levels induced by CLP. Both Rim and BQ123 also increased AVP levels 12 h after CLP. The blockade of central CB1 and ETA receptors in the late phase of sepsis increased the survival rate, reduced body temperature and increased the circulating AVP levels.

Central mediators of the zymosan-induced febrile response

Abstract Background: Zymosan is a fungal cell wall protein-carbohydrate complex that is known to activate inflammatory pathways through the Toll-like receptors and is commonly used to induce fever. Nevertheless, the central mediators that are involved in the zymosan-induced febrile response are only partially known. Methods: The present study evaluated the participation of prostaglandins, substance P, endothelin-1 (ET-1), and endogenous opioids (eOPs) in the zymosan-induced febrile response by using inhibitors and antagonists in male Wistar rats. Results: Both nonselective (indomethacin) and selective (celecoxib) cyclooxygenase inhibitors reduced the febrile response induced by an intraperitoneal (i.p.) injection of zymosan. Indomethacin also blocked the increase in the prostaglandin E2 levels in the cerebrospinal fluid. An intracerebroventricular injection of the neurokinin-1, ETB, and μ-opioid receptor antagonists also reduced the febrile response induced by the i.p. injected zymosan. Moreover, the μ-opioid receptor antagonist CTAP also reduced the febrile response induced by intra-articular injection of zymosan. Conclusions: These results demonstrate that prostaglandins, substance P, ET-1, and eOPs are central mediators of the zymosan-induced febrile response.