Hellíada Vasconcelos Chaves

Antinociceptive and anti-inflammatory activities of a sulfated polysaccharide isolated from the green seaweed Caulerpa cupressoides

BACKGROUND Red and brown algae sulfated polysaccharides (SPs) have been widely investigated as antinociceptive and/or anti-inflammatory agents; however, no description of these biological properties concerning green algae SPs have been reported. Caulerpa curpressoides (Chlorophyta) presents three SPs fractions (Cc-SP1, Cc-SP2, and Cc-SP3). Anticoagulant (in vitro) and anti- and pro-thrombotic (in vivo) effects of Cc-SP2 had been recently reported. We evaluated the effects of Cc-SP2 using models of nociception and acute inflammation in vivo. METHODS Male Swiss mice received Cc-SP2 (iv) 30 min prior to receiving 0.6% acetic acid (10 ml/kg, ip), 1% formalin (20 μl, sc) or were subjected to thermal stimuli (51 ± 1 °C). Cc-SP2 was injected sc to male Wistar rats in a peritonitis model or a paw edema model using carrageenan (ip or ipl, 500 μg). To analyze the systemic effects, Cc-SP2 (27 mg/kg, sc) was administrated to both genders mice before waiting for 14 days. RESULTS Cc-SP2 (3, 9 or 27 mg/kg) reduced (p < 0.05) the number of writhes induced by acetic acid by 57, 89.9 and 90.6%, respectively, the licking time in the first (9 or 27 mg/kg with 42.47 and 52.1%, respectively) and the second (3, 9 or 27 mg/kg with 68.95, 82.34 and 84.61%, respectively) phases. In the hot-plate test, the antinociceptive effect of Cc-SP2 (9 mg/kg) was primarily observed at 60 min (26.7 ± 1.2 s), with its effect reversed by naloxone (8.6 ± 1.3 s), suggesting the involvement of the opioid system. Cc-SP2 (3, 9 or 27 mg/kg, sc, p < 0.05) showed anti-inflammatory effects by decreasing neutrophils migration by 64, 69 and 73%, respectively, and potently reduced the paw edema, especially at the second (0.16 ± 0.02, 0.16 ± 0.03 and 0.12 ± 0.05 ml) and third (0.16 ± 0.03, 0.18 ± 0.02 and 0.14 ± 0.04 ml) hours, respectively. Cc-SP2 did not cause hepatic or renal alterations or affect body mass or the macroscopy of the organs examined (p > 0.05). Histopathological analyses of the liver and kidney showed that both organs were affected by Cc-SP2 treatment, but these effects were considered reversible. CONCLUSION The results indicate that the analgesic and anti-inflammatory effects of Cc-SP2 could be of biomedical applicability as a new, natural tool in pain and acute inflammatory conditions.

Antinociceptive and Anti-Inflammatory Activities of Sulphated Polysaccharides from the Red Seaweed Gracilaria cornea

Seaweeds have attracted special interest as good sources of sulphated polysaccharides (SP) for use in pharmaceutical industries and biotechnology. In this study, we evaluated the effects of SP from the red seaweed Gracilaria cornea (Gc-TSP) in nociceptive and inflammatory models. In mice, Gc-TSP (3, 9 or 27 mg/kg) significantly reduced nociceptive responses, as measured by the number of writhes, at all tested doses. In a formalin test, Gc-TSP significantly reduced licking time in both phases of the test at a dose of 27 mg/kg. In a hot-plate test, the antinociceptive effect was observed only in animals treated with 27 mg/kg of Gc-TSP, suggesting that the analgesic effect occurs through a central action mechanism at the highest dose. Gc-TSP (3, 9 or 27 mg/kg) caused only a slight reduction in neutrophil migration in the rat peritoneal cavity. However, lower doses of Gc-TSP (3 and 9 mg/kg) significantly inhibited paw oedema induced by carrageenan, especially at 3 hr after treatment. Reduction in oedema was confirmed by myeloperoxidase activity in the affected paw tissue. In addition, treatment (s.c.) of animals with different doses of Gc-TSP inhibited paw oedema induced by dextran within the first hour in all doses tested. After 14 consecutive days of intraperitoneal administration of Gc-TSP (9 mg/kg), we measured the wet weight of the liver, kidney, heart, spleen and thymus and performed biochemical, haematological and histopathological evaluations. No systemic damage was found. These results indicate that Gc-TSP possesses analgesic and anti-inflammatory effects and is a potentially important tool worthy of further study.

Experimental Model of Zymosan-Induced Arthritis in the Rat Temporomandibular Joint: Role of Nitric Oxide and Neutrophils

Aims. To establish a new model of zymosan-induced temporomandibular joint (TMJ) arthritis in the rat and to investigate the role of nitric oxide. Methods. Inflammation was induced by an intra-articular injection of zymosan into the left TMJ. Mechanical hypernociception, cell influx, vascular permeability, myeloperoxidase activity, nitrite levels, and histological changes were measured in TMJ lavages or tissues at selected time points. These parameters were also evaluated after treatment with the nitric oxide synthase (NOS) inhibitors L-NAME or 1400 W. Results. Zymosan-induced TMJ arthritis caused a time-dependent leucocyte migration, plasma extravasation, mechanical hypernociception, and neutrophil accumulation between 4 and 24 h. TMJ immunohistochemical analyses showed increased inducible NOS expression. Treatment with L-NAME or 1400 W inhibited these parameters. Conclusion. Zymosan-induced TMJ arthritis is a reproducible model that may be used to assess both the mechanisms underlying TMJ inflammation and the potential tools for therapies. Nitric oxide may participate in the inflammatory temporomandibular dysfunction mechanisms.

Heme oxygenase/carbon monoxide-biliverdin pathway may be involved in the antinociceptive activity of etoricoxib, a selective COX-2 inhibitor

The aim of this study was to assess the interaction between the heme oxygenase-1/ biliverdin/carbon monoxide (HO-1/BVD/CO) and cyclooxygenase-2 (COX-2) pathways in the writhing test. Mice were pretreated with 0.1, 1 or 10 mg/kg, ip etoricoxib, a selective COX-2 inhibitor, or with one of the following HO-1/BVD/CO pathway modulators: 1, 3 or 9 mg/kg, sc ZnPP IX, a specific HO-1 inhibitor, 0.3, 1 or 3 mg/kg, sc hemin, a substrate of the HO-1/BVD/CO pathway; or 0.00025, 0.025 or 2.5 μmol/kg, sc DMDC, a CO donor. Mice pretreated with etoricoxib or one of the HO-1/BVD/CO pathway modulators received an injection of acetic acid (ip) after 30 and 60 min, respectively. Next, the number of writhes was quantified between 0 and 30 min after stimulus injection. In another series of experiments, ineffective doses of etoricoxib were co-administered with hemin or DMDC and an effective dose of etoricoxib with ZnPP IX, followed by an acetic acid injection. Four hours after the acetic acid injection, levels of bilirubin, which is a product of BVD conversion by the BVD reductase enzyme, in the peritoneal lavage were determined. Hemin or DMDC reduced (p<0.05) the number of writhes, but ZnPP IX potentiated (p<0.05) the effect of acetic acid by increasing (p < 0.05) the number of writhes. The co-administration of etoricoxib with hemin or DMDC reduced (p<0.05) the number of writhes. However, the analgesic effect of etoricoxib was not observed in the presence of ZnPP IX. Pretreatment with ZnPP IX reduced bilirubin levels, but etoricoxib pretreatment significantly increased the bilirubin concentration in peritoneal exudates. The data obtained from these experiments showed that the HO-1/BVD/CO pathway was activated in the acetic acid-induced abdominal writhing model. The analgesic effect of etoricoxib was at least partially dependent on the participation of the HO-1/BVD/CO pathway.

A lectin from the green seaweed Caulerpa cupressoides reduces mechanical hyper-nociception and inflammation in the rat temporomandibular joint during zymosan-induced arthritis

Seaweed lectins have been widely investigated as anti-nociceptive and anti-inflammatory agents. This study analyzed the anti-nociceptive and anti-inflammatory responses of a lectin from the green seaweed Caulerpa cupressoides (CcL) on zymosan-induced arthritis of the rat temporomandibular joint (TMJ). Rats received i.v. CcL 30 min prior to injection of zymosan (2mg/art.) or 0.9% saline into the left TMJ. Mechanical hyper-nociception was measured by the electronic von Frey method at baseline and 4h after zymosan injection. Animals were euthanized 6h after zymosan injection and the synovial fluid was collected for leukocyte counting and myeloperoxidase activity assessment. Other animals were treated with ZnPP-IX (3mg/kg; s.c.), a specific heme oxygenase-1 pathway inhibitor, and naloxone (10 μg/art.), a nonselective opioid receptor antagonist. TMJ tissues were excised to perform histopathological and immunohistochemistry analyses. CcL (0.1, 1 or 10mg/kg) significantly reduced zymosan-induced hyper-nociception (81, 83 and 89.5%, respectively) and inhibited the leukocyte influx (77.3, 80.7 and 98.5%, respectively) compared with the zymosan-only group, as confirmed by myeloperoxidase activity; however, treatment with naloxone or ZnPP-IX did not revert the effects of CcL (10mg/kg), suggesting that the naloxone-sensitive opioid and heme oxygenase-1 pathways are not involved. CcL also reduced the leukocyte influx and the expression of IL-1β and TNF-α in the TMJ, based on histopathological and immunohistochemistry analyses, respectively. Therefore, CcL reduces TMJ hyper-nociception and inflammation with a mechanism that is partially dependent on TNF-α and IL-1β inhibition. CcL reveals a potentially valuable alternative tool for future studies of TMJ disorders.

Tephrosia toxicaria Pers. reduces temporomandibular joint inflammatory hypernociception: The involvement of the HO‐1 pathway

We investigated both the efficacy and the sub‐chronic toxicity of Tephrosia toxicaria Pers. in the zymosan‐induced temporomandibular joint (TMJ) inflammatory hypernociception in rats evaluating the possible role of heme oxygenase‐1 (HO‐1).

Mechanisms involved in the anti-inflammatory action of a polysulfated fraction from Gracilaria cornea in rats.

The anti-inflammatory mechanisms of the sulfated polysaccharidic fraction obtained from red marine alga Gracilaria cornea (Gc-FI) were investigated using a paw edema model induced in rats by different inflammatory agents (carrageenan, dextran, serotonin, bradykinin, compound 48/80 or L-arginine). Gc-FI at the doses of 3, 9 or 27 mg/kg, subcutaneously - s.c., significantly inhibited rat paw edema induced by carrageenan and dextran, as confirmed by myeloperoxidase and Evans’ blue assessments, respectively. Gc-FI (9 mg/kg, s.c.) inhibited rat paw edema induced by histamine, compound 48/80 and L-arginine. Additionally, Gc-FI (9 mg/kg, s.c.) inhibited Cg-induced edema in animals with intact mast cells but did not inhibit that with degranulated mast cells by compound 48/80, revealing a protective role on mast cell membranes. Gc-FI down-regulated the IL-1β, TNF-α and COX-2 mRNA and protein levels compared with those of the carrageenan group, based on qRT-PCR and immunohistochemistry analyses. After inhibition with ZnPP IX, a specific heme oxygenase-1 (HO-1) inhibitor, the anti-inflammatory effect of Gc-FI was not observed in Cg-induced paw edema, suggesting that the anti-inflammatory effect of Gc-FI is, in part, dependent on the integrity of the HO-1 pathway. Gc-FI can target a combination of multiple points involved in inflammatory phenomena.

Peripheral antinociception and anti-inflammatory effects of sulphated polysaccharides from the alga Caulerpa mexicana.

Sulphated polysaccharides from marine algae are widely used in biotechnological and pharmaceutical areas. In this study, we evaluated the effects of sulphated polysaccharides from the green marine alga Caulerpa mexicana (Cm‐SPs) in nociceptive and inflammatory models in rodents. Cm‐SPs (10 or 20 mg/kg), administered i.v. in Swiss mice, significantly reduced nociceptive responses, as measured by the number of writhes in response to acetic acid. Cm‐SPs (10 or 20 mg/kg) also reduced second‐phase responses in the formalin test, but did not exhibit a significant antinociceptive effect in the hot plate test, suggesting that its antinociceptive action occurs through a peripheral mechanism. Cm‐SPs (5, 10 or 20 mg/kg), administered s.c. in wistar rats 1 hr before carrageenan, dextran, histamine or serotonin, were tested in paw oedema models. Cm‐SPs (10 or 20 mg/kg) reduced carrageenan‐induced paw oedema and myeloperoxidase activity in the paw. In addition, Cm‐SPs (20 mg/kg) inhibited dextran‐ or histamine‐induced paw oedema, but not serotonin‐induced oedema, suggesting that histamine is the major target of Cm‐SPs anti‐oedematogenic activity. Finally, Cm‐SPs (20 mg/kg) administered in mice did not show significant signs of toxicity. In conclusion, Cm‐SPs appear to be promising natural modulatory agents for pain and inflammatory conditions.

Peripheral antinociception and anti-edematogenic effect of a sulfated polysaccharide from Acanthophora muscoides

BACKGROUND Sulfated polysaccharides from red marine algae have presented a variety of potentially therapeutic biological effects, however, their antinocicpetive and anti-inflammatory properties are not well understood. METHODS Male Swiss mice were pretreated with a sulfated polysaccharidic fraction obtained from the marine alga Acanthophora muscoides (AmII) (1, 3 or 9 mg/kg, iv) 30 min prior to either receiving an injection of 0.8% acetic acid or 1% formalin or prior to a thermal stimulus. AmII (1, 3 or 9 mg/kg, sc) was evaluated on carrageenan-, dextran- bradykinin-, histamine- and serotonin-induced rat paw edema models. AmII (500 μg, sc) was also injected into the paw. Additionally, mice were treated with the total sulfated polysaccharides from A. muscoides (Am-TSP) (20 mg/kg, ip) for 14 days. RESULTS AmII reduced the number of acetic acid-induced writhes and licking time in the second phase of the formalin test, but it did not alter the response latency in the hot plate test, suggesting that its antinociceptive action occurs through a peripheral mechanism. AmII did not reduce carrageenan-induced paw edema and MPO activity. However, it reduced dextran-, histamine- and serotonin-induced paw edemas, but not bradykinin-induced edema, suggesting that histamine is the major target of AmII anti-edematogenic activity. AmII injected into the paw did not evoke local edema. Furthermore, Am-TSP induced no consistent signs of systemic damage, as revealed by body mass, organs wet weight and by biochemical, hematological and histopathological analyses. CONCLUSION AmII has important antinociceptive and anti-inflammatory properties and represents an important therapeutic agent warranting future studies.

Protective effect of Chresta martii extract on ethanol-induced gastropathy depends on alpha-2 adrenoceptors pathways but not on nitric oxide, prostaglandins or opioids.

ETHNOPHARMACOLOGICAL RELEVANCE Species of Chresta genus- are recognized by the population of northeastern Brazil as traditional herbs used to treat gastric diseases and other disorders. AIM OF THE STUDY This work aimed to find out the action mechanism of Chresta martii hydro alcoholic extract gastro protective effect in the model of ethanol-induced gastropathy. MATERIAL AND METHODS Gastropathy was assessed by percentual damaged area determination in photographs of mice opened stomachs. Fasted mice treated with ethanol 99.9% (0.2 ml/animal, p.o.) were pre-treated with Chresta martii hydro alcoholic extract (HAE) (50, 100 or 200 mg/kg, p.o.), ranitidine (80 mg/kg, p.o.) or saline (5 ml/kg; p.o.) in different experimental sets, in which pharmacological tools (naloxone, indomethacin, N(ω)-Nitro-L-arginine methyl ester hydrochloride (L-NAME) or yohimbine) were added in order to clarify a possible action mechanism. Animals were sacrificed 30 min after ethanol challenge to stomach analysis. Determination of non-protein sulfhydryl groups and tissue hemoglobin, besides histological assessment (H&E) were taken to fully characterize the HAE gastro protective effect. RESULTS HAE (100 and 200 mg/kg) was able to protect mucosa against ethanol gastropathy in presence of three (naloxone, indomethacin and L-NAME) of four antagonist/inhibitor tools. The HAE effect was reversed only by yohimbine, showing the alpha-2 adrenoceptors participation on gastro protective effect of this extract. HAE histological characteristics, NP-SH and Hb were compatible with the protective effects. CONCLUSIONS HAE possesses gastroprotective effects in an ethanol-induced gastropathy model in mice, corroborating the traditional use of this family of plants to treat gastric disorders. This activity is mediated by alpha-2 adrenoceptors activation, but not by nitric oxide release, opioid receptor activation or prostaglandin synthesis. HAE also has antioxidant activity that is thought to either play a role in this biological activity or to be a byproduct of alpha-2 adrenergic complex activation.