Ricardo de Oliveira Correia

Immunological and parasitological parameters in Schistosoma mansoni-infected mice treated with crude extract from the leaves of Mentha x piperita L.

Schistosomiasis is a chronic disease caused by an intravascular trematode of the genus Schistosoma. Praziquantel is the drug used for treatment of schistosomiasis; nevertheless failure of treatment has been reported. Consequently, the identification of new effective schistosomicidal compounds is essential to ensure the effective control of schistosomiasis in the future. In this work we investigated the immunomodulatory and antiparasitic effects of the crude leaves extract of Mentha x piperita L. (peppermint) on murine Schistosomiasis mansoni. Female Balb/c mice were infected each with 50 S. mansoni cercariae and divided into three experimental groups: (I) untreated; (II) treated daily with M. x piperita L. (100mg/kg) and III) treated on 1/42/43 days post-infection with Praziquantel (500mg/kg). Another group with uninfected and untreated mice was used as a control. Subsequently, seven weeks post-infection, S. mansoni eggs were counted in the feces, liver and intestine. Worms were recovered by perfusion of the hepatic portal system and counted. Sera levels of IL-10, IL-5, IL-13, IFN-γ, IgG1, IgE and IgG2a were assayed by ELISA. Animals treated with a daily dose of M. x piperita L. showed increased sera levels of IL-10, IFN-γ, IgG2a and IgE. Besides, M. x piperita L. treatment promoted reduction in parasite burden by 35.2% and significant decrease in egg counts in the feces and intestine.

Menthol and Menthone Associated with Acetylsalicylic Acid and Their Relation to the Hepatic Fibrosis in Schistosoma mansoni Infected Mice

Schistosomiasis is an important parasitic disease caused by Schistosoma mansoni, an intravascular trematode. Schistosomiasis treatment is limited to just one drug, Praziquantel (PZQ). Thus, studies on new antischistosomal compounds are of fundamental importance to disease control. Here we report on the effects of Mentha piperita L. compounds – menthol and menthone – in association with acetylsalicylic acid (ASA) in the regulation of hepatic fibrosis caused by schistosomiasis granulomas. Six different groups of Swiss rats were infected with 80 cercariae. Two groups received only menthol and menthol treatment at different concentrations (30 and 50 mg/kg); two groups received treatment with the same concentration of menthol and menthol, but associated the ASA. All groups received treatment for 14 consecutive days from the 35 days after the parasitic infection. In addition, three other groups were used: uninfected and untreated group, infected and untreated group and infected group treated with the commercial drug (single dose). Parasitological, cytological and histological analyses were performed. Results showed a significant reduction on the number of eosinophils found in the peritoneal cavity lavage (LPC) in all treated groups and on the number of eosinophils found in the blood of PZQ treated group, in the blood of the group treated with 30 mg/kg of Mentaliv® and in the blood of group treated with 50 mg/kg Mentaliv® + ASA when compared to the infected group. All treated groups presented a reduction in the parasite load, represented by the number of S. mansoni eggs, in the experimental group treated with 30 mg/kg of menthol and menthone a 62.80% reduction was observed and in the experimental group treated with 50 mg/kg of menthol and menthone + ASA a reduction of 64.21% was observed. In the liver histological analysis we observed that all Mentaliv® treated groups expressed a unique cytological profile, with diffused cells through the granuloma. In the experimental group treated with 50 mg/kg of Mentaliv® + ASA it was possible to observe the formation of type III collagen fibers, a typical wound healing characteristic. Our data strongly suggest that both the hepatic fibrosis and the inflammatory process were regulated through the schistosomiasis granulomatous process after treatment with menthol and menthone associated with ASA.

Robust Phenotypic Activation of Eosinophils during Experimental Toxocara canis Infection

Eosinophils are multifunctional cells that have cytotoxic proinflammatory activities and stimulate CD4+ T-cells in experimental models of allergy and parasitic infections. Eosinophils, when exposed to antigens, are activated, expressing the CD38/CD69 molecules and exhibited increased expression of major histocompatibility complex (MHC-II), CD80 and CD86, suggesting they play a role upon Toxocara canis antigen stimulation. In the present study, we evaluated the profile of eosinophils using conventional and image flow cytometry upon experimental T. canis infection. T. canis antigens induced a robust activation on this subset, contributing to the immune responses elicited in the experimental model for T. canis-associated visceral larva migrans syndrome. Data analysis demonstrated that, during murine T. canis infection, eosinophils from peripheral blood, spleen, and bone marrow presented upregulated expression of CD69/MHC-II/CD80/CD86. As opposed to splenic and bone marrow eosinophils, circulating eosinophils had increased expression of activation markers upon T. canis infection. The enhanced connectivity between eosinophils and T-cells in T. canis-infected mice in all three compartments (peripheral blood, spleen, and bone marrow) also supports the hypothesis that eosinophils may adopt a role during T. canis infection. Moreover, in vitro T. canis antigen stimulation resulted in activation and upregulation of co-stimulatory-related molecules by bone marrow-derived eosinophils. Our findings are evidence of activation and upregulation of important activation and co-stimulatory-related molecules in eosinophils and suggest a reshape of activation hierarchy toward eosinophils during experimental T. canis infection.

Cytotoxic Effects and Production of Cytokines Induced by the Endophytic Paenibacillus polymyxa RNC-D In Vitro

BACKGROUND Prominent among all the organisms that have a potential value for the production of new medicines, are endophytes, fungi and bacteria that live inside plants without harming them. In this study, a total lyophilized extract (TLE) of Paenibacillus polymyxa RNC-D was used. The P. polymyxa lineages are known for their capacity to segregate a large number of extracellular enzymes and bioactive substances. METHODS The TLE of Paenibacillus polymyxa RNC-D was tested in cell viability assays for cytotoxicity and cytokine production in BALB/3T3 and J774A.1 cell lineages. RESULTS A 50% mortality rate of fibroblasts (BALB/3T3) was observed in the 1.171±0.161 mg/mL and 0.956±0.112 mg/mL doses after 48 and 72 hours, respectively, as well as a 50% mortality rate of macrophage cells (J774A.1) in the 0.994±0.170 mg/mL and 0.945±0.280 mg/mL doses after 48 and 72 hours, respectively. The ≈1 mg/mL concentration significantly affected the kinetic of growth in all the measured periods. The extract induced apoptosis and necrosis 24 hours after the ≈1 mg/mL concentration in both tested lineages. The treatment with the ≈1 mg/mL concentration led to the production of TNF-α and IFN-γ cytokines in 24 hours. IL-12 and IL-10 began to be detected as a result of the treatment with 0.1 mg/mL. However, with the 0.5 mg/mL dose in 24 hours, a significant reduction in IL-10 was observed. CONCLUSION Our data suggest that the TLE of P. polymyxa RNC-D modulated the production of cytokines with different patterns of immune response in a dose-dependent way.