Ricardo Basto Souza

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.

Neuroprotective Effects of Sulphated Agaran from Marine Alga Gracilaria cornea in Rat 6-Hydroxydopamine Parkinson's Disease Model: Behavioural, Neurochemical and Transcriptional Alterations.

Parkinsons disease (PD) is a multifactorial disease associated with the degeneration of dopaminergic neurons and behavioural alterations. Natural bioactive compounds may provide new therapeutic alternatives for neurodegenerative disorders, such as PD. The sulphated polysaccharides isolated from marine algae are heterogenic molecules that show different biological activities. The red marine alga Gracilaria cornea has a sulphated polysaccharide (SA‐Gc) with structure and anti‐inflammatory and antinociceptive activities reported in the literature. Therefore, this study aimed to evaluate the neuroprotective effects of SA‐Gc in rat model PD induced by 6‐hydroxydopamine (6‐OHDA). Firstly, we established the PD model in rats, induced by an intrastriatal injection (int.) of 6‐OHDA, followed by a single administration of SA‐Gc (15, 30 or 60 μg; int.). On the 14th day, behavioural tests were performed. After killing, brain areas were dissected and used for neurochemical and/or transcriptional analyses. The results showed that SA‐Gc (60 μg, int.) promoted neuroprotective effects in vivo through reducing the oxidative/nitroactive stress and through alterations in the monoamine contents induced by 6‐OHDA. Furthermore, SA‐Gc modulated the transcription of neuroprotective and inflammatory genes, as well as returning behavioural activities and weight gain to normal conditions. Thus, this study reports the neuroprotective effects of SA‐Gc against 6‐OHDA in rats.

Mechanisms involved in antinociception induced by a polysulfated fraction from seaweed Gracilaria cornea in the temporomandibular joint of rats

Temporomandibular disorder is a common clinical condition involving pain in the temporomandibular joint (TMJ) region. This study assessed the antinociceptive effects of a polysulfated fraction from the red seaweed Gracilaria cornea (Gc-FI) on the formalin-induced TMJ hypernociception in rats and investigated the involvement of different mechanisms. Male Wistar rats were pretreated with injection (sc) of saline or Gc-FI 1h before intra- TMJ injection of formalin to evaluate the nociception. The results showed that pretreatment with Gc-FI significantly reduced formalin-induced nociceptive behavior. Moreover, the antinociceptive effect of the Gc-FI was blocked by naloxone (a non-selective opioid antagonist), suggesting the involvement of opioids selective receptors. Thus, the pretreatment with selective opioids receptors antagonists, reversed the antinociceptive effect of the Gc-FI in the TMJ. The Gc-FI antinociceptive effect depends on the nitric oxide/cyclic GMP/protein kinase G/ATP-sensitive potassium channel (NO/cGMP/PKG/K+ATP) pathway because it was prevented by pretreatment with inhibitors of nitric oxide synthase, guanylate cyclase enzyme, PKG and a K+ATP blocker. In addition, after inhibition with a specific heme oxygenase-1 (HO-1) inhibitor, the antinociceptive effect of the Gc-FI was not observed. Collectively, these data suggest that the antinociceptive effect induced by Gc-FI is mediated by μ/δ/κ-opioid receptors and by activation NO/cGMP/PKG/K+ATP channel pathway, besides of HO-1.

Impact of the Chronic Omega‐3 Fatty Acids Supplementation in Hemiparkinsonism Model Induced by 6‐Hydroxydopamine in Rats

Parkinsons disease (PD) is characterized by a progressive degeneration of dopaminergic neurons in the substantia nigra. The neuronal degeneration may result from the convergence of a number of different pathogenic factors, including apoptosis, excitotoxicity and oxidative stress. Many studies emphasize the importance of omega‐3 polyunsaturated fatty acids (ω‐3 PUFAs) in vital processes such as maintenance of the properties of cell membranes and the participation in signal transduction and biodynamic activity of neuronal membranes. In this study, the protective effect of ω‐3 PUFA administration on the 6‐hydroxydopamine (6‐OHDA) model of PD in rats was investigated. ω‐3 PUFA (1.5 and 3.0 g/kg) was orally administered by gavage during 28 consecutive days to male Wistar rats. On the 4th day, hemiparkinsonism was induced through intrastriatal injection of 6‐OHDA. On the 25th day, the animals were submitted to behavioural analysis. On the 28th day, after euthanasia, the brain areas were collected for neurochemical evaluation. ω‐3 PUFAs (1.5 and 3.0 g/kg) restored monoamine and amino acid levels on the striatum from hemiparkinsonian rats, followed by reduction in the number of apomorphine‐induced rotations and promotion of a partial locomotor recovery. In addition, ω‐3 PUFAs (1.5 and 3.0 g/kg) decreased the lipid peroxidation levels and nitrite levels in the brain areas from hemiparkinsonian rats. Thus, this study suggests that supplementation with ω‐3 PUFAs prevents behavioural and neurochemical disturbances induced by 6‐OHDA, presenting a potential neuroprotective action.

In vitro activities of kappa -carrageenan isolated from red marine alga Hypnea musciformis : Antimicrobial, anticancer and neuroprotective potential

This study assessed the antioxidant, antimicrobial, anticancer and neuroprotective activities of the kappa(k)-carrageenan isolated from the red alga Hypnea musciformis (Hm-SP). The chemical spectrum of the k-carrageenan from Hm-SP was confirmed by Fourier transform infrared (FT-IR) spectroscopy. Hm-SP revealed an antibacterial and antifungal action against Staphylococcus aureus and Candida albicans, respectively. Hm-SP did not promoted cytotoxic effects against Human breast cancer (MCF-7) and Human neuroblastoma (SH-SY5Y) cell-lines. However, it was observed a significant reduction of the cellular proliferation capacity in these cancer cells in presence of the Hm-SP. Furthermore, Hm-SP showed neuroprotective activity in 6-hydroxydopamine-induced neurotoxicity on SH-SY5Y cells by modulation of the mitochondria transmembrane potential and reducing Caspase 3 activity. In addition, Hm-SP demonstrates low antioxidant potential and did not induce significant cytotoxic effects or changes in the cell proliferation on Balb/c 3T3 mouse fibroblast cell-line. In summary, our data suggest that Hm-SP shows antimicrobial, anticancer and neuprotective activities.

Local administration of Tiludronic Acid downregulates important mediators involved in periodontal tissue destruction in experimental periodontitis in rats

OBJECTIVE The purpose of this study was to evaluate whether local administration of TIL could influence the expression of the inflammatory mediators IL-1β, TNF-α, MMP-8 and COX-2 in rats with experimental periodontitis (EP). METHODS Twenty-four adult male rats (Rattus norvegicus, albinus, Wistar) were assigned to groups C, EP, EP-TIL (CControl group, EP-Periodontitis groups). On EP groups, a ligature was placed around maxillary 2nd molars on day 1. On group EP-TIL, 20 μL of TIL solution (1 mg/kg body weight) was injected into the subperiosteal palatal area adjacent to the maxillary 2nd molar every other day until euthanasia (day 11). Alveolar bone loss was morphometrically analyzed. mRNA expressions of IL-1β, TNF-α, MMP-8 and COX-2 were assessed by qPCR. IL-1β, TNF-α, MMP-8 and COX-2 were immunohistochemically analyzed. Data were analyzed statistically. RESULTS Group EP-TIL presented reduced alveolar bone loss when compared with group EP (p < 0.05). Group EP-TIL presented decreased mRNA expressions of IL-1β, TNF-α, MMP-8 and COX-2 and reduced immunolabeling of IL-1β, TNF-α and MMP-8 when compared with group EP (p < 0.05). No differences regarding the immunolabeling of COX-2 were found when group EP-TIL was compared with the other groups (p > 0.05). CONCLUSION Within the limits of this study, it can be concluded that local administration of TIL downregulates important mediators involved in periodontal tissue destruction in ligature-induced periodontitis in rats.