Arsenic bioaccumulation and biotransformation in different tissues of Nile tilapia (Oreochromis niloticus): A comparative study between As(III) and As(V) exposure and evaluation of antagonistic effects of selenium.

The speciation of arsenic in fish has been widely investigated, but bioaccumulation and biotransformation of inorganic As in different tissues of Nile tilapia (Oreochromis niloticus) are not fully understood. The present study aimed to investigate the bioaccumulation of As in Nile tilapia, as well as to evaluate the distribution of the main arsenic species (As(III), As(V), MMA, DMA, and AsB) in liver, stomach, gill, and muscle, after controlled exposures to As(III) and As(V) at concentrations of 5.0 and 10.0 mg L-1 during periods of 1 and 7 days. Total As was determined by inductively coupled plasma mass spectroscopy (ICP-MS). For both exposures (As(III) and As(V)), the total As levels after 7-day exposure were highest in the liver and lowest in the muscle. Overall, the Nile tilapia exposed to As(III) showed higher tissue levels of As after the treatments, compared to As(V) exposure. Speciation of arsenic present in the tissues employed liquid chromatography coupled to ICP-MS (LC-ICP-MS), revealing that the biotransformation of As included As(V) reduction to As(III), methylation to monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), and subsequent conversion to nontoxic arsenobetaine (AsB), which was the predominant arsenic form. Finally, the interactions and antagonistic effects of selenium in the bioaccumulation processes were tested by the combined exposure to As(III), the most toxic species of As, together with tetravalent selenium (Se(IV)). The results indicated a 4-6 times reduction of arsenic toxicity in the tilapia.

Losartan improves intestinal mucositis induced by 5-fluorouracil in mice.

Intestinal mucositis (IM) is a common side effect of 5-fluorouracil (5-FU)-based chemotherapy, which negatively impacts therapeutic outcomes and delays subsequent cycles of chemotherapy resulting in dose reductions and treatment discontinuation. In search of new pharmacological alternatives that minimize your symptoms, this work set out to study the effect of losartan (LOS), a receptor type I (AT1) angiotensin II antagonist, on intestinal mucositis induced by 5-FU. Intestinal mucositis was induced by a single intraperitoneal administration of 5-FU (450 mg/kg) in Swiss mice. Losartan (5, 25 or 50 mg/kg) or saline was orally administered 30 min before 5-FU and daily for 4 days. On 4th day, the animals were euthanized and segments of small intestine were collected to evaluate histopathological alterations (morphometric analysis), concentration of inflammatory cytokines, oxidative stress markers and genic expression of NF-κB p65, Fn-14 and TWEAK. Weight evaluation and changes in leukogram were also analyzed. 5-FU induced intense weight loss, leukopenia and reduction in villus height compared to saline group. Losartan (50 mg/kg) prevented 5-FU-induced inflammation by decreasing in the analyzed parameters compared to the 5-FU group. Our findings suggest that 50 mg/kg of losartan prevents the effects of 5-FU on intestinal mucosa in mice.

Anti-hypernociceptive and anti-inflammatory effects of JM-20: A novel hybrid neuroprotective compound.

The present study examines the possible effect of the novel hybrid molecule JM-20 (3-ethoxycarbonyl-2-methyl-4-(2-nitrophenyl)-411-dihydro-1H-pyrido[2,3-b] [1,5] benzodiazepine) on pain-related behaviours in a persistent pain model (5% formalin test) and in the neutrophil migration events during the inflammatory process. It further introduces JM-20 in a chronic constriction injury (CCI) model to clarify the possible subjacent mechanisms with its consequent clinical relevance. A single administration of JM-20 (20 or 40 mg/kg, per os [p.o.]) decreased licking/biting exclusively in the tonic phase of the formalin test in a GABA/benzodiazepine (BZD) receptor antagonist flumazenil-sensitive manner. JM-20 reduced in vivo neutrophil migration, rolling and adhesion to the endothelium induced by intraperitoneal administration of carrageenan in mice. In addition, plasma extravasation and tumour necrosis factor alpha production in the peritoneal fluid were decreased. Treatment with JM-20 (20 mg/kg, p.o.) for 7 days after CCI reduced mechanical hypersensitivity in a NG-monomethyl-l-arginine (L-NMMA)/methylene blue/glibenclamide-sensitive manner. Histopathological signs of Wallerian degeneration (WD) of the sciatic nerve were also attenuated, as well as interleukin-1 beta release in the spinal cord. The nitrate/nitrite concentration was increased centrally and did not show differences at the peripheral nerve level. The findings of this study suggest JM-20 can decrease persistent pain. A transient activity of its BDZ portion on nociceptive pathways mediated by GABA/BDZ receptors in association with its anti-inflammatory properties could be at least partially involved in this effect. JM-20 decreased CCI-induced mechanical hypersensitivity via the l-arginine/nitric oxide (NO)/cyclic GMP-sensitive ATP-sensitive potassium channel pathway. Its neuroprotective ability by preventing WD could be implicated in its anti-neuropathic mechanisms.

Antinociceptive and antioxidant effects of extract enriched with active indole alkaloids from leaves of Tabernaemontana catharinensis A. DC.

ETHNOPHARMACOLOGICAL RELEVANCE: Ethnopharmacological knowledge is important for the identification of active compounds from natural products. Pain may have different aetiologies with complex mechanisms. Tabernaemontana catharinensis A. DC. is well known for indole alkaloids, being used empirically in folk medicine, with antimicrobial and anti-inflammatory as well as antiofidic actions among others. AIM OF THE STUDY: This work aims to evaluate the antinociceptive and antioxidant effect in mice of the alkaloids extract from leaves of Tabernaemontana catharinensis A. DC. (AITc). MATERIALS AND METHODS: The AITc was produced by ultrasound and acid-base extraction, and the chemical composition was evaluated by high resolution mass spectrometry. Male mice (Mus musculus), Swiss, were used for in vivo tests. The AITc was administrated at doses of 1.0, 5.0, and 10.0 mg/kg in acetic acid model, formalin, tail-immersion, hot plate, and open field tests, and compared to saline, morphine, or diazepam controls, depending on the test. The toxicological, biochemical, haemogram and antioxidant effect were evaluated in mouse organs such as liver, brain, kidneys, spleen and stomach. RESULTS: In total, 10 compounds were identified in the AITc, being from the indole alkaloids from the ibogan and corynanthean classes. The extract in doses ranging from 5.0 to 10.0 mg/kg showed an antinociceptive effect for acetic acid, inhibiting by 47.7% and 61.6%. In the same line, reductions of 47.1% (first phase) and 43.6% (second phase) were observed for the 5.0 mg/kg dose in the formalin test. However, tail-immersion and hot plate tests did not show considerable modifications in the latency period, while in the open field test there was an inhibition of only 5.1%. It was observed no differences in NO levels and total antioxidant status of the mice in any of the studie tissues. CONCLUSIONS: The results justify the use of this plant in traditional medicine. in vivo tests indicate that these compounds possess central and peripheral mechanisms of action. This is study that reports the nociceptive action of these alkaloids, also including toxicity tests, which are intended to guarantee the safety of use of extracts of this plant.

Bacterial cellulose membrane associated with red propolis as phytomodulator: Improved healing effects in experimental models of diabetes mellitus.

Since early times, propolis has been used in folk medicine. The red propolis, collected in the northeast region of Brazil has been highlighted due to its popular use as an antimicrobial, with anti-inflammatory and healing properties, which are associated with its chemical composition. Here, we combine a bacterial membrane with red propolis to treat wounds of diabetic mice. This work aims to evaluate a biocurative from bacterial cellulose associated with red propolis in diabetic mice as wound healing model. Biocuratives from bacterial cellulose membrane and different extracts of red propolis were produced. The qualification and quantification of the presence of propolis chemical compounds in the membrane were investigated through high-resolution mass spectrometry (HRMS). Tests in vivo with biocuratives were performed on Swiss male diabetic mice induced by estroptozotocin. The animals were submitted to a surgical procedure and a single lesion was produced in the dorsal region, which was treated with the biocuratives. Macroscopic assessments were performed at 2, 7 and 14 postoperative days, and biopsies were collected on days 0, 7 and 14 for histological analysis, myeloperoxidase enzyme activity (MPO) and cytokines (TNF-α, IL-1ß, and TGF-ß). Altogether, ten compounds were identified in membranes and five were further quantified. The ethyl acetate extract showed more red propolis markers, and the most prevalent compound was Formononetin with 4423.00-2907.00 µg.g-1. Macroscopic analyses demonstrated that the two groups treated with red propolis (GMEBT and GMEAE) showed significantly greater healing capabilities compared to the control groups (GS and GMS). An increase in leukocyte recruitment was observed, confirmed by the activity of the enzyme myeloperoxidase (MPO) in GMEBT and GMEAE groups. The levels of TNF-α were significantly higher in wounds stimulated with red propolis, as well as in TGF-ß (GMEBT and GMEAE) on day 7. This was different from the IL-1ß levels that were higher in the control groups (GS and GMS). In summary, the biocuratives produced in this work were able to accelerate the wound healing process in a diabetic mouse model. In this way, the traditional knowledge of red propolis activity helped to create a biotechnological product, which can be used for diabetic wound healing purpose.

Diabetes-induced Neuropathic Mechanical Hyperalgesia Depends on P2X4 Receptor Activation in Dorsal Root Ganglia.

Peripheral diabetic neuropathy (PDN) manifests in 50-60% of type I and II diabetic patients and is the major cause of limb amputation. Adequate therapy for PDN is a current challenge. There are evidences that the activation of the P2X4 receptor (P2X4R) expressed on microglial cells of the central nervous system takes part in the development of neuropathic pain. However, there is an open question: Is P2X4R activation on dorsal root ganglia (DRG) involved in the development of neuropathic pain? To answer this question, this study verified the involvement of P2X4R expressed in DRG cells on diabetes-induced neuropathic mechanical hyperalgesia in rats. We found that intrathecal or ganglionar (L5-DRG) administration of a novel P2X4R antagonist (PSB-15417) or intrathecal administration of oligodeoxynucleotides (ODN)-antisense against the P2X4R reversed diabetes-induced neuropathic mechanical hyperalgesia. The DRG of the diabetic neuropathic rats showed an increase in P2X4R expression, and the DRG immunofluorescence suggested that P2X4R is expressed mainly in satellite glial cells (SGC). Finally, our study showed a functional expression of P2X4R in SGCs of the rat's DRG, because the P2X4R agonist BzATP elicits an increase in intracellular calcium concentration in SGCs, which was reduced by PSB-15417. These findings indicate that P2X4R activation in DRG is essential to diabetes-induced neuropathic mechanical hyperalgesia. Therefore, this purinergic receptor in DRG could be an interesting therapeutic target for quaternary P2X4R antagonists that do not cross the hematoencephalic barrier, for the control of neuropathic pain, preserving central nervous system functions.

Anti-allodynic Effect of Mangiferin in Rats With Chronic Post-ischemia Pain: A Model of Complex Regional Pain Syndrome Type I.

The present study reproduces chronic post-ischemia pain (CPIP), a model of complex regional pain syndrome type I (CRPS-I), in rats to examine the possible transient and long-term anti-allodynic effect of mangiferin (MG); as well as its potential beneficial interactions with some standard analgesic drugs and sympathetic-mediated vasoconstriction and vasodilator agents during the earlier stage of the pathology. A single dose of MG (50 and 100 mg/kg, p.o.) decreased mechanical allodynia 72 h post-ischemia-reperfusion (I/R). MG 100 mg/kg, i.p. (pre- vs. post-drug) increased von Frey thresholds in a yohimbine and naloxone-sensitive manner. Sub-effective doses of morphine, amitriptyline, prazosin, clonidine and a NO donor, SIN-1, in the presence of MG were found to be significantly anti-allodynic. A long-term anti-allodynic effect at 7 and 13 days post-I/R after repeated oral doses of MG (50 and 100 mg/kg) was also observed. Further, MG decreased spinal and muscle interleukin-1ß concentration and restored muscle redox status. These results indicate that MG has a transient and long-term anti-allodynic effect in CPIP rats that appears to be at least partially attributable to the opioid and α2 adrenergic receptors. Additionally, its anti-inflammatory and antioxidant mechanisms could also be implicated in this effect. The association of MG with sub-effective doses of these drugs enhances the anti-allodynic effect; however, an isobolographic analysis should be performed to define a functional interaction between them. These findings suggest the possible clinical use of MG in the treatment of CRPS-I in both early sympathetically maintained pain and long-term sympathetically independent pain.

Chitosan Membrane Modified With a New Zinc(II)-Vanillin Complex Improves Skin Wound Healing in Diabetic Rats.

The treatment of chronic wounds is considered a public health problem. When the condition affects at-risk groups such as those with diabetics, it becomes a great clinical challenge. In this work, we evaluated the healing effects of a new zinc complex, [Zn(phen)(van)2], identified as ZPV, which was synthesized, characterized and associated with chitosan (CS) membranes and tested on cutaneous wounds of diabetic rats. Chitosan membranes were modified by Schiff base reaction with the complex under two experimental conditions (14 and 21 days), resulting in membranes with concentrations of complex equal to 0.736 µmol cm-2 (CS-ZPV1) and 1.22 µmol cm-2 (CS-ZPV2). Release assays in aqueous medium indicated that the membranes release the complex gradually when exposed to an aqueous medium. Diabetes was inducted in Wistar rats using 40 mg/kg (i.v.) streptozotocin. On the 7th day after diabetic induction, a circular excision on the skin (1.0 cm) was performed with a punch. The lesions were treated with the pure chitosan membrane and the membrane associated with the zinc-vanillin complex in two different doses. Skin samples were subjected to macroscopic and histopathological analyses, cytokine (TNF-α, IL-1ß, and IL-10) quantification and reverse transcriptase polymerase chain reaction (TGF-ß and VEGF) assays. The analyses showed a decrease in wound size, reepithelialization, angiogenic stimulus, collagen deposition, and reduced levels of TNF-α and IL-1ß as well as increased IL-10 and gene expression of TGF-ß and VEGF. The evaluated parameters suggest that CS-ZPV in the two concentrations tested may be effective in the treatment of chronic wounds.

Pharmacological Beta-Adrenergic Receptor Activation Attenuates Neutrophil Recruitment by a Mechanism Dependent on Nicotinic Receptor and the Spleen.

The aim of this study was to identify the effect of beta-adrenergic receptor activation on neutrophil migration in experimental peritonitis elucidating the neuroimmune components involved such as nicotinic receptors and the spleen. Mice pre-treated with mecamylamine (nicotinic antagonist) and propranolol (beta-adrenergic antagonist) or splenectomized animals were treated with isoproterenol (beta-adrenergic agonist) prior to intraperitoneal injection of carrageenan. After 4 h, the infiltrating neutrophils and the local cytokine/chemokine levels were evaluated in the peritoneal lavage. The effect of isoproterenol on neutrophil chemotaxis was investigated in a Boyden chamber. Isoproterenol inhibited neutrophil trafficking, reducing the cytokine/chemokine release and neutrophil chemotaxis. Surprisingly, the isoproterenol effect on neutrophil migration was totally reverted by splenectomy and mecamylamine pre-treatment. In contrast, the inhibitory effect of nicotine on neutrophil migration was abrogated only by splenectomy but not by propranolol pre-treatment. Collectively, our data show that beta-adrenergic receptor activation regulates the acute neutrophil recruitment via splenic nicotinic receptor.

Anti-hypernociceptive effect of mangiferin in persistent and neuropathic pain models in rats.

The present study examines the possible effect of the glucosylxanthone mangiferin (MG) on pain-related behaviors in a tonic acute pain model (formalin test at 5%) and in a chronic constriction injury (CCI) model to clarify the underlying transient and long-term mechanisms. Acute administration of MG (10-100mg/kg, i.p.) reduced licking/biting exclusivity in the tonic phase of formalin test in a naloxone and yohimbine-sensitive manner. This effect was enhanced by a nonselective nitric oxide synthase (NOS) inhibitor (NG-monomethyl-L-arginine) and by a non-competitive N-methyl-D-aspartate (NMDA) antagonist (ketamine), but it was reversed by the NOS substrate (L-arginine). Pre-treatment with intrathecal yohimbine prevented the anti-hypernociceptive effect of systemic MG. Pre-treatment during 4 days before surgical and 3 days after CCI with MG (50mg/kg, i.p.) reduced mechanical hypernociception and decreased the signs of Wallerian degeneration (WD) of the sciatic nerve. MG improved the PC-12 cellular viability exposure to glutamate-mediated neuronal death, also involved in neuropathic pain. The findings of this study suggest that MG shows ability to decrease tonic pain in the formalin test. A transient activity of this xanthone on nociceptive pathways mediated by α2 adrenergic receptors in cooperation with the opioid system could be involved, at least in part, in this effect. Its neuroprotective effect by preventing WD in mononeuropathic rats could be implicated in the mechano-antihypernociceptive long term mechanisms.

Structural studies of an anti-inflammatory lectin from Canavalia boliviana seeds in complex with dimannosides.

Plant lectins, especially those purified from species of the Leguminosae family, represent the best-studied group of carbohydrate-binding proteins. Lectins purified from seeds of the Diocleinae subtribe exhibit a high degree of sequence identity notwithstanding that they show very distinct biological activities. Two main factors have been related to this feature: variance in key residues influencing the carbohydrate-binding site geometry and differences in the pH-dependent oligomeric state profile. In this work, we have isolated a lectin from Canavalia boliviana (Cbol) and solved its x-ray crystal structure in the unbound form and in complex with the carbohydrates Man(α1-3)Man(α1-O)Me, Man(α1-4)Man(α1-O)Me and 5-bromo-4-chloro-3-indolyl-α-D-mannose. We evaluated its oligomerization profile at different pH values using Small Angle X-ray Scattering and compared it to that of Concanavalin A. Based on predicted pKa-shifts of amino acids in the subunit interfaces we devised a model for the dimer-tetramer equilibrium phenomena of these proteins. Additionally, we demonstrated Cbol anti-inflammatory properties and further characterized them using in vivo and in vitro models.

Peripheral inflammatory hyperalgesia depends on the COX increase in the dorsal root ganglion.

It is well established that dorsal root ganglion (DRG) cells synthesize prostaglandin. However, the role that prostaglandin plays in the inflammatory hyperalgesia of peripheral tissue has not been established. Recently, we have successfully established a technique to inject drugs (3 µL) directly into the L5-DRG of rats, allowing in vivo identification of the role that DRG cell-derived COX-1 and COX-2 play in the development of inflammatory hyperalgesia of peripheral tissue. IL-1ß (0.5 pg) or carrageenan (100 ng) was administered in the L5-peripheral field of rat hindpaw and mechanical hyperalgesia was evaluated after 3 h. Administration of a nonselective COX inhibitor (indomethacin), selective COX-1 (valeryl salicylate), or selective COX-2 (SC-236) inhibitors into the L5-DRG prevented the hyperalgesia induced by IL-1ß. Similarly, oligodeoxynucleotide-antisense against COX-1 or COX-2, but not oligodeoxynucleotide-mismatch, decreased their respective expressions in the L5-DRG and prevented the hyperalgesia induced by IL-1ß in the hindpaw. Immunofluorescence analysis demonstrated that the amount of COX-1 and COX-2, constitutively expressed in TRPV-1(+) cells of the DRG, significantly increased after carrageenan or IL-1ß administration. In addition, indomethacin administered into the L5-DRG prevented the increase of PKCε expression in DRG membrane cells induced by carrageenan. Finally, the administration of EP1/EP2 (7.5 ng) or EP4 (10 µg) receptor antagonists into L5-DRG prevented the hyperalgesia induced by IL-1ß in the hindpaw. In conclusion, the results of this study suggest that the inflammatory hyperalgesia in peripheral tissue depends on activation of COX-1 and COX-2 in C-fibers, which contribute to the induction and maintenance of sensitization of primary sensory neurons.

NDP-MSH inhibits neutrophil migration through nicotinic and adrenergic receptors in experimental peritonitis.

Melanocortin is a potent anti-inflammatory molecule. However, little is known about the effect of melanocortin on acute inflammatory processes such as neutrophil migration. In the present study, we investigated the ability of [Nle4, D-Phe7]-melanocyte-stimulating hormone (NDP-MSH), a semisynthetic melanocortin compound, in the inhibition of neutrophil migration in carrageenin-induced peritonitis model. Herein, subcutaneous pretreatment with NDP-MSH decreased neutrophil trafficking in the peritoneal cavity in a dose-dependent manner. NDP-MSH inhibited vascular leakage, leukocyte rolling, and adhesion and reduced peritoneal macrophage inflammatory protein 2, but not TNF-alpha, IL-1beta, IL-10, and keratinocyte-derived chemokine production. In addition, the effect on neutrophil migration was reverted by the pretreatment with both propranolol (a nonselective beta-adrenergic antagonist) and mecamylamine (a nonselective nicotinic antagonist) but not by splenectomy surgery. Moreover, NDP-MSH intracerebroventricular administration inhibited neutrophil migration, indicating participation of the central nervous system. Our results propose that the NDP-MSH effect may be due to a spleen-independent neuro-immune pathway that efficiently regulates excessive neutrophil recruitment to tissues.

Molecular modeling of lectin-like protein from Acacia farnesiana reveals a possible anti-inflammatory mechanism in Carrageenan-induced inflammation.

Acacia farnesiana lectin-like protein (AFAL) is a chitin-binding protein and has been classified as phytohaemagglutinin from Phaseolus vulgaris (PHA). Legume lectins are examples for structural studies, and this family of proteins shows a remarkable conservation in primary, secondary, and tertiary structures. Lectins have ability to reduce the effects of inflammation caused by phlogistic agents, such as carrageenan (CGN). This paper explains the anti-inflammatory activity of AFAL through structural comparison with anti-inflammatory legume lectins. The AFAL model was obtained by molecular modeling and molecular docking with glycan and carrageenan were performed to explain the AFAL structural behavior and biological activity. Pisum sativum lectin was the best template for molecular modeling. The AFAL structure model is folded as a ß sandwich. The model differs from template in loop regions, number of ß strands and carbohydrate-binding site. Carrageenan and glycan bind to different sites on AFAL. The ability of AFAL binding to carrageenan can be explained by absence of the sixth ß -strand (posterior ß sheets) and two ß strands in frontal region. AFAL can inhibit pathway inflammatory process by carrageenan injection by connecting to it and preventing its entry into the cell and triggers the reaction.

Agglutinin isolated from the red marine alga Hypnea cervicornis J. Agardh reduces inflammatory hypernociception: involvement of nitric oxide.

Hypnea cervicornis agglutinin (HCA), a lectin isolated from the red marine alga has been previously shown to have an antinociceptive effect. In the present study in rats, mechanisms of action of HCA were addressed regarding mechanical hypernociception induced by carrageenan, ovalbumin (as antigen), and also by prostaglandin E(2) in rats. The lectin administered intravenously inhibited carrageenan- and antigen-induced hypernociception at 1, 3, 5 and 7h. This inhibitory effect was completely prevented when lectin was combined with mucin, demonstrating the role of carbohydrate-binding sites. The inhibition of inflammatory hypernociception by HCA was associated with the prevention of neutrophil recruitment to the plantar tissue of rats but was not associated with the inhibition of the release of pro-hypernociceptive cytokines (TNF-alpha, IL-1 beta and CINC-1). HCA also blocked mechanical hypernociception induced by PGE(2), which was prevented by the administration of nitric oxide synthase inhibitors. These results were corroborated by the increased circulating levels of NO metabolites following HCA treatment. These findings suggest that the anti-hypernociceptive effects of HCA are not associated with the inhibition of pro-inflammatory cytokine production. However, these effects seem to involve the inhibition of neutrophil migration and also the increase in NO production.

Antinociceptive activity and toxicology of the lectin from Canavalia boliviana seeds in mice.

The aim of the present study was to evaluate the potential antinociceptive and toxicity of Canavalia boliviana lectin (CboL) using different methods in mice. The role of carbohydrate-binding sites was also investigated. CboL given to mice daily for 14 days at doses of 5 mg/kg did not cause any observable toxicity. CboL (1, 5, and 10 mg/kg) administered to mice intravenously inhibited abdominal constrictions induced by acetic acid and the two phases of the formalin test. In the hot plate and tail immersion tests, the same treatment of CboL induced significant increase in the latency period. In the hot plate test, the effect of CboL (5 mg/kg) was reversed by naloxone (1 mg/kg), indicating the involvement of the opioid system. In the open-field and rota-rod tests, the CboL treatment did not alter animals' motor function. These results show that CboL presents antinociceptive effects of both central and peripheral origin, involving the participation of the opioid system via lectin domain.

Pharmacological analysis of the neutrophil migration induced by D. rostrata lectin: involvement of cytokines and nitric oxide.

In the present study, we investigated the involvement of resident cell and inflammatory mediators in the neutrophil migration induced by chemotactic activity of a glucose/mannose-specific lectin isolated from Dioclea rostrata seeds (DrosL). Rats were injected i.p. with DrosL (125-1000 microg/cavity), and at 2-96 h thereafter the leukocyte counts in peritoneal fluid were determined. DrosL-induced a dose-dependent neutrophil migration accumulation, which reached maximal response at 24 h after injection and declines thereafter. The carbohydrate ligand nearly abolished the neutrophil influx. Pre-treatment of peritoneal cavities with thioglycolate which increases peritoneal macrophage numbers, enhanced neutrophil migration induced by DrosL by 303%. However, the reduction of peritoneal mast cell numbers by treatment of the cavities with compound 48/80 did not modify DrosL-induced neutrophil migration. The injection into peritoneal cavities of supernatants from macrophage cultures stimulated with DrosL (125, 250 and 500 microg/ml) induced neutrophil migration. In addition, DrosL treatment induced cytokines (TNF-alpha, IL-1beta and CINC-1) and NO release into the peritoneal cavity of rats. Finally, neutrophil chemotaxis assay in vitro showed that the lectin (15 and 31 microg/ml) induced neutrophil chemotaxis by even 180%. In conclusion, neutrophil migration induced by D. rostrata lectin occurs by way of the release of NO and cytokines such as IL-1beta, TNF-alpha and CINC-1.

Vascular permeability, neutrophil migration and edematogenic effects induced by the latex of Cryptostegia grandiflora.

Inflammatory responses have been described as occurring after exposure to some latex materials. In this study pro-inflammatory activity in the latex of Cryptostegia grandiflora was investigated. The soluble proteins of the latex (CgLP) were isolated from the whole latex and evaluated by in vivo assays. CgLP induced strong inflammatory activity mediated by neutrophil migration, enlarging vascular permeability and increasing myeloperoxidase activity locally in rats. CgLP-induced inflammation was observed in peritonitis, paw edema and air push models. In addition, CgLP caused hyperemia in a healing model. The peritonitis effect was lost when CgLP was previously boiled suggesting the involvement of pro-inflammatory proteins. Thioglycollate increased the neutrophil migration induced by CgLP, but not by fMLP. Mast cell depletion provoked by 40/80 compound did not modify the course of inflammation triggered by CgLP, being similar to fMLP, which suggested that neutrophil migration was induced by direct mechanism mediated by macrophages. Neutrophil migration stimulated by CgLP was strongly inhibited by Dexamethasone and to a lesser extent by Thalidomide, indicating the involvement of cytokines in mediating neutrophil infiltration. Celecoxib and Indomethacin were inhibitory suggesting the involvement of prostaglandins. Cimetidine was effective only in the initial phase of edema. PCA 4248 was ineffective. It is concluded that the latex of C. grandiflora is a potent inflammatory fluid, and also that laticifer proteins may be implicated in this process.

Antinociceptive and anti-inflammatory effects of a mucin-binding agglutinin isolated from the red marine alga Hypnea cervicornis.

The agglutinin from the red marine alga Hypnea cervicornis (HCA) was tested in models of nociception and inflammation. The role of carbohydrate-binding sites and the systemic toxicity were assessed. HCA (10(-1), 1, and 10 mg/kg) administered i.v. to mice inhibited writhes induced by acetic acid and, at 10 mg/kg, inhibited the second phase of the formalin test, but did not alter the response latency in the hot-plate test. HCA (1 mg/kg) administered i.v. to rats reduced carrageenan-induced paw edema at 1, 2, and 3 h after challenge, but not edema induced by dextran. The neutrophil migration induced by both N-formyl-methionyl-leucyl-phenylalanine (fMLP) and carrageenan was inhibited by HCA at 10(-1), 1, and 10 mg/kg. The combination of HCA (1 mg/kg) and its ligand mucin reversed the lectin inhibitory effect on carrageenan-induced neutrophil migration and acetic acid-induced writhes. The i.v. treatment of rats with HCA (1 mg/kg) for 7 days did not affect body mass; liver, kidney or heart wet weight; blood leukocyte counts; urea, creatinine or serum transaminase activity; or macroscopy of the organs examined. In short, H. cervicornis agglutinin showed important antinociceptive and anti-inflammatory activity via interaction with the lectin carbohydrate-binding site.