Th1/Th2 cytokines' expression and production by propolis-treated mice.

AIM OF THE STUDY: Propolis is a natural product extensively used in food and beverages to improve health and to prevent diseases, showing immunomodulatory properties. The goal of this work was to evaluate the effect of propolis administration over a short-term to mice on Th1 (IL-2 and IFN-gamma) and Th2 (IL-4 and IL-10) cytokines' expression and production. MATERIALS AND METHODS: Propolis was administered for 3 days to mice by gavage, spleens were removed and RNA was extracted to assess cytokines' expression by real-time PCR. Supernatants of spleen cell cultures were used for cytokines determination by ELISA. RESULTS: Propolis administration to mice did not affect IL-2, IL-4 and IL-10 expression and production, while IFN-gamma production was inhibited in the splenocyte cultures stimulated or not by Con A. CONCLUSIONS: Since IFN-gamma is a pro-inflammatory cytokine, our data suggest that propolis administration over a short-term to mice may be associated with anti-inflammatory effects in vivo, and further assays could check propolis efficiency in inflammatory diseases.

Th1/Th2 cytokine production by clove-treated mice.

Although clove possesses several biological and therapeutic properties, its immunomodulatory action has not been fully investigated. The goal of this work was to investigate the effect of administration of the water extract of clove over a short-term to BALB/c mice on Th1 (IFN-gamma and IL-2) and Th2 (IL-4 and IL-10) cytokine production. After treatment, spleen cells were aseptically removed and cells were stimulated with concanavalin A. Supernatants of cell cultures were used for cytokine determination by ELISA. The chemical composition of the extract was also carried out, revealing that eugenol(4-allyl-2-methoxyphenol) was the major component in our sample. Although the anti-inflammatory action of clove has been mentioned, our data showed that clove administration to mice did not influence the Th1/Th2 cytokine balance. Further studies dealing with cytokine expression and production will provide a better understanding of clove's immunomodulatory and anti-inflammatory actions, using different extract concentrations and different intake periods.

Propolis effects on pro-inflammatory cytokine production and Toll-like receptor 2 and 4 expression in stressed mice.

INTRODUCTION: Propolis is a beehive product and its immunomodulatory action has been well documented; however, little is known concerning its activity on the immune system of stressed mice. This work investigated a possible role of propolis against the immunosuppressive effects induced by stress in mice, assessing the pro-inflammatory cytokine (IL-1beta and IL-6) production and Toll-like receptor (TLR-2 and TLR-4) expression by spleen cells. METHODS: BALB/c mice were divided into 3 groups: G1 was considered control; G2 was submitted to restraint stress for 3 days, and G3 was treated with propolis and immediately submitted to stress. After sacrifice, spleens were removed and TLR-2 and TLR-4 gene expression was analyzed, as well as the pro-inflammatory cytokine production. Serum corticosterone levels were determined by radioimmunoassay as a stress indicator. RESULTS: Stressed mice, treated or not with propolis, produced higher corticosterone levels, whereas IL-1beta and IL-6 production was inhibited. TLR-2 and TLR-4 expression was inhibited in stressed mice, while propolis exerted an immunorestorative role in TLR-4 expression. The immunosuppressive effects on IL-1beta and IL-6 production and on TLR expression by stressed mice might have occurred due to a higher corticosterone production during stress. CONCLUSION: Propolis treatment did not antagonize the inhibitory effects on pro-inflammatory cytokine production, however it restored at least partially TLR2 mRNA expression and counteracted the inhibition on TLR-4 expression in stressed animals, contributing to the recognition of microorganisms during stressful conditions.

Propolis effect on Th1/Th2 cytokines production by acutely stressed mice.

AIM OF THE STUDY: Propolis has gained special attention due to its biological properties, however, little is known about its immunomodulatory effects in stress conditions. The purpose of this study was to investigate propolis effect on Th1/Th2 cytokines production by spleen cells of acutely stressed mice. Serum corticosterone concentration was determined as a stress indicator. MATERIALS AND METHODS: Male BALB/c mice were submitted to restraint stress and treated with propolis (200mg/kg) for 3 days. Supernatants of splenocytes cultures were assessed for Th1/Th2 cytokines determination. RESULTS: Regarding Th1 cytokines production, no alterations were seen in IL-2 production; however, IFN-gamma production was inhibited in stressed mice, even when treated with propolis. As to Th2 cytokines, IL-4 was inhibited in stressed mice, but normal levels were seen when these animals were treated with propolis. No significant differences were found in IL-10 production between the experimental groups. Stressed groups (treated or not with propolis) showed higher corticosterone concentrations in comparison to control group. CONCLUSIONS: Data suggest that propolis treatment was not able to counteract the stress-induced immunosuppressive effect on IFN-gamma production; however, propolis showed an immunorestorative role, increasing IL-4 production in stressed mice, favoring humoral immune response during stress. Since the exact mechanisms of this natural product on immune system are still unclear, further studies are still required for a better comprehension of propolis use as a therapeutic alternative against the stress-induced negative effects that could lead to the development of various diseases.

Green brazilian propolis action on macrophages and lymphoid organs of chronically stressed mice.

Stress is a generic term that summarizes how psychosocial and environmental factors influence physical and mental well-being. The interaction between stress and immunity has been widely investigated, involving the neuroendocrine system and several organs. Assays using natural products in stress models deserve further investigation. Propolis immunomodulatory action has been mentioned and it has been the subject of scientific investigation in our laboratory. The aim of this study was to evaluate if and how propolis activated macrophages in BALB/c mice submitted to immobilization stress, as well as the histopathological analysis of the thymus, bone marrow, spleen and adrenal glands. Stressed mice showed a higher hydrogen peroxide (H(2)O(2)) generation by peritoneal macrophages, and propolis treatment potentiated H(2)O(2) generation and inhibited nitric oxide (NO) production by these cells. Histopathological analysis showed no alterations in the thymus, bone marrow and adrenal glands, but increased germinal centers in the spleen. Propolis treatment counteracted the alterations found in the spleen of stressed mice. New research is being carried out in order to elucidate propolis immunomodulatory action during stress.

Effect of a leukotriene inhibitor (MK886) on nitric oxide and hydrogen peroxide production by macrophages of acutely and chronically stressed mice.

We evaluated the effect of a leukotriene inhibitor (MK886) on nitric oxide (NO) and hydrogen peroxide (H(2)O(2)) production by peritoneal macrophages of mice subjected to acute and chronic stress. Acute stress was induced by keeping mice immobilized in a tube for 2 h. Chronic stress was induced over a 7-day period by the same method, but with increasing duration of immobilization. The effects of MK886 were investigated in-vitro after incubation with peritoneal macrophages, and in-vivo by submitting mice to stress and treating them daily with MK886. Supernatants of macrophage cultures were collected for NO determination and adherent cells were used for H(2)O(2) determination. Macrophages from mice submitted to acute or chronic stress showed no alterations in H(2)O(2) production. However, macrophages of acutely and chronically stressed mice showed inhibition of NO after incubation with MK886 in-vitro. Administration of MK886 to chronically stressed mice increased generation of H(2)O(2) and inhibited production of NO. Our data suggest an important role of leukotrienes in NO synthesis, which is important in controlling replication of several infectious agents, mainly in stressed and immunosuppressed animals.

Effect of Baccharis dracunculifolia D.C. (Asteraceae) extracts and its isolated compounds on macrophage activation.

Baccharis dracunculifolia D.C. (Asteraceae), a shrub which grows wild in Brazil, is the main botanical source of Brazilian green propolis. Since Brazilian propolis shows an immunomodulatory activity, the goal of this work was to evaluate the action of B. dracunculifolia extracts and some of its isolated compounds on reactive oxygen intermediate (H(2)O(2)) production by macrophages obtained from male BALB/c mice. The results showed that the leaf (Bd-L) (25, 50, and 100 microg mL(-1)), leaf rinse (Bd-LR) (25 microg mL(-1)), and the root (Bd-R) (25 microg mL(-1)) extracts enhanced H2O2 release by macrophages. A phytochemical study of the root and leaves of B. dracunculifolia was carried out. The chromatographic fractionation of Bd-R, using several techniques, afforded the isolation of baccharis oxide (1), friedelanol (2), viscidone (11), 11-hydroxy-10,11-dihydro-euparin (12), and 6hydroxy-tremetona (13), while Bd-LR gave the following isolated compounds: baccharis oxide (1), friedelanol (2), isosakuranetin (3), aromadendrin-4'-methyl ether (4), dihydrocumaric acid (5), baccharin (6), hautriwaic acid lactone (7), hautriwaic acid acetate (8), drupanin (9), and cumaric acid (10). Among the isolated compounds, baccharis oxide (1) and friedelanol (2) increased H2O2 production at a concentration of 100 microM. This is the first time that the presence of compounds 7, 8, 12, and 13 in B. dracunculifolia has been reported. Based on these results it is suggested that the crude extracts and some isolated compounds from B. dracunculifolia display an immunomodulatory action.