Models of inflammation: Carrageenan- or complete Freund's Adjuvant (CFA)-induced edema and hypersensitivity in the rat

The anti-inflammatory and immunomodulatory potential of braylin: Pharmacological properties and mechanisms by in silico, in vitro and in vivo approaches

Braylin belongs to the group of natural coumarins, a group of compounds with a wide range of pharmacological properties. Here we characterized the pharmacological properties of braylin in vitro, in silico and in vivo in models of inflammatory/immune responses. In in vitro assays, braylin exhibited concentration-dependent suppressive activity on activated macrophages. Braylin (10–40 μM) reduced the production of nitrite, IL-1β, TNF-α and IL-6 by J774 cells or peritoneal exudate macrophages stimulated with LPS and IFN-γ. Molecular docking calculations suggested that braylin present an interaction pose to act as a glucocorticoid receptor ligand. Corroborating this idea, the inhibitory effect of braylin on macrophages was prevented by RU486, a glucocorticoid receptor antagonist. Furthermore, treatment with braylin strongly reduced the NF-κB-dependent transcriptional activity on RAW 264.7 cells. Using the complete Freund’s adjuvant (CFA)-induced paw inflammation model in mice, the pharmacological properties of braylin were demonstrated in vivo. Braylin (12.5–100 mg/kg) produced dose-related antinociceptive and antiedematogenic effects on CFA model. Braylin did not produce antinociception on the tail flick and hot plate tests in mice, suggesting that braylin-induced antinociception is not a centrally-mediated action. Braylin exhibited immunomodulatory properties on the CFA model, inhibiting the production of pro-inflammatory cytokines IL-1β, TNF-α and IL-6, while increased the anti-inflammatory cytokine TGF-β. Our results show, for the first time, anti-inflammatory, antinociceptive and immunomodulatory effects of braylin, which possibly act through the glucocorticoid receptor activation and by inhibition of the transcriptional activity of NF-κB. Because braylin is a phosphodiesterase-4 inhibitor, this coumarin could represent an ideal prototype of glucocorticoid receptor ligand, able to induce synergic immunomodulatory effects.

Effect of new polyherbal formulations DF1911, DF2112 and DF2813 on CFA induced inflammation in rat model

BACKGROUND

Aim of the present study was to evaluate anti-inflammatory activity of newly developed polyherbal formulations DF1911, DF2112 and DF2813. These newly developed formulations are modifications of Dashamoola, a well known Ayurvedic formulation, along with addition of new plants.

METHODS

Complete Freund's adjuvant (CFA) induced inflammation in rat was used as an experimental model. Effects of the treatment in rats were monitored by physiological and biochemical parameters, histopathology and through gene expression studies.

RESULTS

Diclofenac sodium showed maximum percentage inhibition (56.8 ± 3.5%) of paw edema followed by Dashamoola Kwatha (19.9 ± 1.8%). Among test formulations treated groups, DF1911 at 250 mg/kg bw (48.2 ± 5.4%, p < 0.001) and DF2112 at 250 mg/kg bw (49.9 ± 3.5%, p < 0.001) showed significant and maximum increase in percentage inhibition of paw edema as compared to Dashamoola Kwatha. Hematological alterations in CFA rats were normalized after treatment with test formulations. Results of serum markers and histopathological observations also supported the activity of formulations. Increased MDA levels in liver tissue of CFA injected animals significantly (p < 0.05) decreased by Diclofenac sodium and test formulation treated groups. DF1911, DF2112 and DF2813 showed down-regulation of IL1-β (~6.4-fold, ~5.2-fold and ~7.6-fold), IL-6 (~1.1-fold, ~1.6-fold and ~1.9-fold), TNF-α (~2.0-fold, ~4.6-fold and ~3.5-fold), and iNOS (~1.2-fold, ~1.8-fold and ~1.1-fold) in inflamed paw tissue compared to negative control group, respectively.

CONCLUSIONS

The anti-inflammatory effects of DF1911 and DF2112 in rats were significantly higher than the Dashamoola Kwatha and are comparable to Diclofenac sodium.

Pharmacological Properties of Riparin IV in Models of Pain and Inflammation

Riparins, natural alkaloids of the alkamide group, can be synthesized by simple methods, enhancing their potential application in pharmaceutical development. Here, the pharmacological properties of riparins were investigated in in vitro and in vivo assays of pain and inflammation in Swiss mice. Inflammatory mediators were measured by radioimmunoassay and Real-Time PCR. Riparins I, II, III and IV (1.56-100 mg/kg; ip) produced dose-related antinociceptive effects in the formalin test, exhibiting ED₅₀ values of 22.93, 114.2, 31.05 and 6.63 mg/kg, respectively. Taking the greater potency as steering parameter, riparin IV was further investigated. Riparin IV did not produce antinociceptive effect on the tail flick, suggesting that its antinociception is not a centrally-mediated action. In fact, riparin IV (1.56-25 mg/kg) produced dose-related antinociceptive and antiedematogenic effects on the complete Freund's adjuvant (CFA)-induced paw inflammation in mice. During CFA-induced inflammation, riparin IV did not modulate either the production of cytokines, TNF-α and IL-10, or COX-2 mRNA expression. On the other hand, riparin IV decreased the PGE₂ levels in the inflamed paw. In in vitro assays, riparin IV did not exhibit suppressive activities in activated macrophages. These results indicate, for the first time, that riparin IV induces antinociceptive and anti-inflammatory effects, possibly through the inhibition of prostanoid production.

Systemic changes following carrageenan-induced paw inflammation in rats

OBJECTIVE AND DESIGN

Carrageenan-induced paw edema has been described as a local and acute inflammatory process. In fact, little is known about the time course and systemic changes following a carrageenan injection. In this study, we examine the systemic changes that follow carrageenan injection in the paw.

METHODS

Acute inflammation was produced by subplantar injection of carrageenan in a hind paw of Sprague-Dawley rats. Saline was used in control rats. Paw volume was measured with a plethysmometer. The hot plate latency test was used to quantify antinociception. C-reactive protein (CRP) levels were measured with a sandwich enzyme immunoassay. Fibrinogen concentration was measured using the gravimetric method. Lung morphometric analysis was performed using an image processing package. Lungs and paws were also examined for tissue factor (TF) and proinflammatory cytokines expression by immunohistochemistry.

RESULTS

We found diverse systemic changes including increased levels of acute phase proteins, such as CRP and fibrinogen, and a lung inflammatory process characterized by lung edema, fibrin deposition, and leukocyte infiltration. An elevated expression of TF, IL-6, IL-1β, and TNFα, was observed in paw and lung tissue sections by immunohistochemical methods.

CONCLUSION

This study provides new evidence that a local carrageenan injection induces a systemic response.

Anti-inflammatory effects of carvacrol: evidence for a key role of interleukin-10

Carvacrol, a phenolic monoterpene, has been reported to possess anti-inflammatory properties. However, the mechanisms involved in its pharmacological properties are currently not well understood. In the present study, the contribution of cytokine modulation to the anti-inflammatory effects of carvacrol was investigated in a classical inflammation model: the complete Freund's adjuvant (CFA)-induced paw inflammation in mice. The paw edema was measured using a plesthismometer. Paw tissue was removed 2h after the inflammatory stimulus to determine the levels of prostaglandin E(2) (PGE(2)) by enzyme immunoassay, the levels of interleukin-1 β (IL-1β), tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10) by ELISA or the mRNA expression of cyclooxygenase-2 (COX-2), IL-1β, TNF-α, and IL-10 by real-time PCR. Administration of carvacrol produced anti-inflammatory effects against CFA-induced inflammation in mice. Treatment of mice with carvacrol at 50 and 100mg/kg attenuated the paw edema and reduced the IL-1β and PGE(2), but not TNF-α, local levels. Similarly, carvacrol (100mg/kg) reduced the COX-2 and IL-1β mRNA expression. The levels of IL-10, an anti-inflammatory cytokine, and the IL-10 mRNA expression in the inflamed paw were enhanced by carvacrol. In addition, the treatment with carvacrol did not reduce the CFA-induced paw edema in IL-10 knockout mice. The present results suggest that carvacrol causes anti-inflammatory effects by reducing the production of inflammatory mediators, such as IL-1β and prostanoids, possibly through the induction of IL-10 release.

Anti-inflammatory properties of rose oxide

Rose-oxide is a fragrance found in roses and rose oil. There are no reports about the pharmacological activity of this molecule. The present study was undertaken to evaluate whether rose-oxide (RO) has anti-inflammatory properties and to investigate possible mechanisms involved with its effects. The anti-inflammatory activity of RO was first suggested by the formalin test in mice, an inflammatory pain model, because intraperitoneal (i.p.) administration of RO (50 and 100mg/kg) inhibited only the late phase of this test. To further investigate the anti-inflammatory properties of RO, the complete Freund's adjuvant (CFA)- and carrageenan-induced paw inflammation models were used. Pre-treatment with RO (50 and 100mg/kg) significantly reduced paw edema at 4, 6 and 24h after the CFA injection. In addition, RO (100mg/kg) reduced the IL-1β, but not TNF-α, local production induced by CFA. Administration of RO (25-100mg/kg) decreased the paw edema induced by carrageenan in rats, which was more evident at 3 and 4h after induction. In addition, neutrophil migration to the hind paw was measured by MPO assay after the carrageenan injection. The MPO activity was significantly inhibited by RO at 25-100mg/kg, 4h after stimulus. In another experimental set, administration of RO (25-100mg/kg) significantly reduced the leukocyte migration in the carrageenan-induced peritonitis model in mice. The results described here are the first report of pharmacological properties of RO and strongly suggest that RO possesses anti-inflammatory activity related to its ability to inhibit the IL-1β production and the leukocyte migration.