Distribution and regulation of cyclooxygenase-2 in carrageenan-induced inflammation

Characterization of protein tyrosine phosphatase H1 knockout mice in animal models of local and systemic inflammation

Background

PTPH1 is a protein tyrosine phosphatase expressed in T cells but its effect on immune response is still controversial. PTPH1 dephosphorylates TCRzeta in vitro, inhibiting the downstream inflammatory signaling pathway, however no immunological phenotype has been detected in primary T cells derived from PTPH1-KO mice. The aim of the present study is to characterize PTPH1 phenotype in two in vivo inflammatory models and to give insights in possible PTPH1 functions in cytokine release.

Methods

We challenged PTPH1-KO mice with two potent immunomodulatory molecules, carrageenan and LPS, in order to determine PTPH1 possible role in inflammatory response in vivo. Cytokine release, inflammatory pain and gene expression were investigated in challenged PTPH1-WT and KO mice.

Results

The present study shows that carrageenan induces a trend of slightly increased spontaneous pain sensitivity in PTPH1-KO mice compared to WT (wild-type) littermates, but no differences in cytokine release, induced pain perception and cellular infiltration have been detected between the two genotypes in this mouse model. On the other hand, LPS-induced TNFα, MCP-1 and IL10 release was significantly reduced in PTPH1-KO plasma compared to WTs 30 and 60 minutes post challenge. No cytokine release modulation was detectable 180 minutes post LPS challenge.

Conclusion

In conclusion, the present study points out a slight potential role for PTPH1 in spontaneous pain sensitivity and it indicates that this phosphatase might play a role in the positive regulation of the LPS-induced cytokines release in vivo, in contrast to previous reports indicating PTPH1 as potential negative regulator of immune response.

Effect of PD98059, a selective MAPK3/MAPK1 inhibitor, on acute lung injury in mice

The aim of the present study is to evaluate the contribution of mitogen-activated protein kinase 1-3 MAPK3/MAPK1) in a model of acute lung inflammation in mice. Injection of carrageenan into the pleural cavity of mice elicited an acute inflammatory response characterized by: accumulation of fluid containing a large number of neutrophils (PMNs) in the pleural cavity, infiltration of PMNs in lung tissues and subsequent adhesion molecule expression (I-CAM and P-selectin), lipid peroxidation, and increased production of tumour necrosis factor-alpha, (TNF-alpha) and interleukin-1beta (IL-1beta). Furthermore, carrageenan induced lung apoptosis (Bax and Bcl-2 expression) as well as nitrotyrosine formation, NF-kB activation, and pJNK expression, as determined by immunohistochemical analysis of lung tissues and the degree of lung inflammation and tissue injury (histological score). Administration of PD98059, an inhibitor of MAPK3/MAPK1 (10 mg/kg) 1 h after carrageenan caused a reduction in all the parameters of inflammation measured. Thus, based on these findings we propose that inhibitors of the MAPK3/MAPK1 signaling pathways, such as PD98059, may be useful in the treatment of various inflammatory diseases.

Synergy of TLR2 and H1R on Cox-2 Activation in Pulpal Cells

Although pulp fibroblasts are a major cell type in dental pulp, their roles in microbial recognition and pulpal inflammation are not well-understood. Considering the pivotal role of Toll-like receptors (TLRs) in the recognition of micro-organisms, we hypothesized that TLRs on pulp fibroblasts may induce inflammatory signals in dental pulp. In human pulp fibroblasts, TLR2, 3, 4, and 5 were constitutively expressed. Stimulation of TLR2 and 3 induced the expression of pro-inflammatory genes such as CXCL10, CCL5, and/or Cox-2 in pulp fibroblasts. Interestingly, histamine synergistically activated TLR2-mediated Cox-2 expression and PGE(2) production. The synergistic effect of histamine is mediated by histamine receptor-1 (H1R). Studies on the intra-cellular signaling pathways revealed that p38 activation is required for the synergistic activation of Cox-2 by TLR2 and histamine. Analysis of these data suggests that TLR2 on pulp fibroblasts, in concert with H1R, can induce an inflammatory response during microbial infection in dental pulp.

Pharmacokinetic-pharmacodynamic modelling of the analgesic effects of lumiracoxib, a selective inhibitor of cyclooxygenase-2, in rats

BACKGROUND AND PURPOSE

This study establishes a pharmacokinetic/pharmacodynamic (PK/PD) model to describe the time course and in vivo mechanisms of action of the antinociceptive effects of lumiracoxib, evaluated by the thermal hyperalgesia test in rats.

EXPERIMENTAL APPROACH

Female Wistar fasted rats were injected s.c. with saline or carrageenan in the right hind paw, followed by either 0, 1, 3, 10 or 30 mg*kg(-1) of oral lumiracoxib at the time of carrageenan injection (experiment I), or 0, 10 or 30 mg*kg(-1) oral lumiracoxib at 4 h after carrageenan injection (experiment II). Antihyperalgesic responses were measured as latency time (LT) to a thermal stimulus. PK/PD modelling of the antinociceptive response was performed using the population approach with NONMEM VI.

RESULTS

A two-compartment model described the plasma disposition. A first-order model, including lag time and decreased relative bioavailability as a function of the dose, described the absorption process. The response model was: LT=LT(0)/(1 +MED). LT(0) is the baseline response, and MED represents the level of inflammatory mediators. The time course of MED was assumed to be equivalent to the predicted profile of COX-2 activity and was modelled according to an indirect response model with a time variant synthesis rate. Drug effects were described as a reversible inhibition of the COX-2 activity. The in vivo estimate of the dissociation equilibrium constant of the COX-2-lumiracoxib complex was 0.24 microg*mL(-1).

CONCLUSIONS

The model developed appropriately described the time course of pharmacological responses to lumiracoxib, in terms of its mechanism of action and pharmacokinetics.

PPAR-alpha contributes to the anti-inflammatory activity of 17beta-estradiol

Because studies have shown that 17beta-estradiol (E2) produces anti-inflammatory effects after various adverse circulatory conditions, we have recently demonstrated that E2 significantly reduced the acute lung injury. Moreover, previous results suggest that peroxisome proliferator-activated receptor-alpha (PPAR-alpha), an intracellular transcription factor activated by fatty acids, plays a role in the control of inflammation. With the aim to characterize the role of PPAR-alpha in estrogen-mediated anti-inflammatory activity, we tested the efficacy of E2 in an experimental model of lung inflammation, carrageenan-induced pleurisy, comparing ovariectomized wild-type (WT) and PPAR-alpha lacking (PPAR-alphaKO) mice. Results indicate that E2-mediated anti-inflammatory activity is weakened in PPAR-alphaKO mice, compared with WT control groups. In particular, E2 was less effective in PPAR-alphaKO, compared with WT mice, in inhibition of cell migration as well as lung injury, NF-kB activation, TNF-alpha production, and inducible nitric-oxide synthase (iNOS) activation. Moreover, macrophages from PPAR-alphaKO were less susceptible to E2-induced iNOS inhibition in vitro compared with macrophages from WT mice. Moreover, the results indicate that PPAR-alpha was required for estrogen receptor up-regulation, following E2 treatment. These results show for the first time that PPAR-alpha contributes to the anti-inflammatory activity of E2.

Suppressive effects on the biosynthesis of inflammatory mediators by Aralia elata extract fractions in macrophage cells

The aim of this study is to elucidate the anti-inflammatory effects of Aralia elata extract fractions (AEEFs). A. elata-ethyl acetate fraction (AEEF) had the strongest antioxidant activity. A. elata-chloroform fraction (AECF) and A. elata-butanol fraction (AEBF) inhibited potently LPS-induced nitrite production from RAW 264.7 macrophage cells. The inhibition of nitric oxide (NO) production by AEEFs was partially due to chemical scavenge of NO and the suppression of inducible NOS (iNOS) transcription level in LPS-induced macrophage cells. In addition, AEEFs inhibited significantly the biosynthesis of Prostaglandin E(2) (PGE(2)), and cyclooxygenase-2, which regulates the synthesis of PGE(2), was attenuated partially by the treatment of AEEFs in LPS-induced macrophage cells. Also, A. elata-methanolic extract (AEME) suppressed remarkably IL-1β and IL-6 level to the basal (more than 99% inhibition) in concentration-dependant manners. Its anti-inflammatory actions might be related with inhibition of NF-κB activation in LPS-stimulated macrophage cells. It is concluded that AEEFs may be useful as a functional food material and an alternative medicine for the relief and retardation of immunological inflammatory responses.

Anti-inflammatory effect of the spirocyclopiperazinium compound LXM-10 in mice and rats

Anti-inflammatory drugs are clinically limited because of their side effects. The aim of this study was to evaluate the anti-inflammatory activities and mechanisms of the spirocyclopiperazinium compound LXM-10 (2, 4-dimethyl-9-beta-phenylethyl-3-oxo-6, 9-diazaspiro[5.5]undecane chloride). We found that LXM-10 produced a significant, dose-dependent decrease in xylene- and carrageenin-induced edema. The anti-inflammatory effect was attenuated by hexamethonium, methyllycaconitine citrate, atropine methylnitrate, and tropicamide. The serum level of TNF-alpha was reduced by LXM-10 in lipopolysaccharide-challenged mice, and this effect was also inhibited by methyllycaconitine and tropicamide. LXM-10 also reduced the prostaglandin E(2) concentration in rat paw tissue. LXM-10 minimised the carrageenin-induced pathological changes and did not affect mice heart rate. LXM-10 did not induce significant changes in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) or alkaline phosphatase (ALP) activity. Median lethal dose (LD(50)) of LXM-10 was 1573.0 micromol/kg. Our findings suggest that LXM-10 has anti-inflammatory effects by activating alpha7 nicotinic and M(4) muscarinic acetylcholine receptors with limited side effects.

Antiinflammatory and antinociceptive activities of Blechnum occidentale L. extract

AIM OF STUDY

Blechnum occidentale L. is a terrestrial fern that ranges from the United States to South America, and is employed in Brazilian folk medicine. In the present study we investigated the antinociceptive and antiinflammatory activities of the methanolic extract of Blechnum occidentale L. (MEB) in animal models of pain and inflammation to support its medicinal use in treatment of inflammatory and pulmonary diseases, urinary infections and liver diseases.

MATERIALS AND METHODS

The antinociceptive activity of MEB was evaluated using the writhing, formalin, and tail flick tests. The antiinflammatory activity of MEB was evaluated in carrageenan-induced paw oedema and neutrophil migration. In order to discard possible non-specific muscle relaxant or sedative effects of MEB, mice motor performance was evaluated in the rota rod test and its toxicity evaluated over 14 days.

RESULTS

Intraperitoneal (IP) administration of MEB (0.01-100mg/kg) produced a dose-related antinociception on acetic acid-induced writhing in mice. Oral administration of MEB, at a different range of doses (100-400 mg/kg), also produced significant antinociceptive effect on the writhing test. Furthermore, treatment with MEB (100 and 200 mg/kg IP) inhibited significantly both the early and late phases of formalin-induced hypernociception in rats. In contrast, treatment with MEB (100 and 200 mg/kg IP) did not prevent the thermal nociception in the tail flick test. The IP administration of MEB (100 and 300 mg/kg) significantly reduced the paw oedema induced by carrageenan. Moreover, systemic treatment with MEB (11-300 mg/kg) reduced the neutrophil migration in the carrageenan-induced migration to the peritoneal cavity. In the rota rod test, MEB-treated mice did not show any significant motor performance alterations with the dose of 300 mg/kg. In addition, over the study duration of 14 days, there were no deaths or toxic signs recorded in the mice given 100 or 1000 mg/kg of MEB.

CONCLUSION

The results described here are the first report of pharmacological studies of Blechnum occidentale L. and indicate that this plant has antinociceptive and antiinflammatory activities which support its folk medicine use.

Different antinociceptive effects of botulinum toxin type A in inflammatory and peripheral polyneuropathic rat models

In addition to inhibition of acetylcholine release in the neuromuscular junction botulinum toxin type A (BoNT-A) also inhibits the release of mediators involved in pain perception. We have investigated the effect of two types of BoNT-A on mechanical hyperalgesia in the rat models of carrageenan-induced hyperalgesia and of paclitaxel-induced peripheral neuropathy. A subplantar (s.p.) injection of BoNT-A in the ipsilateral hindpaw 3 days before carrageenan administration reduced hypersensitivity. Dysport and Botox elicited comparable antihyperalgesic effects. Dysport up to 30 U/kg and Botox up to 20 U/kg did not impair the rat withdrawal nociceptive reflex or the locomotor performance as assessed by the rotarod test. Intraperitoneal administration of the skeletal muscle relaxant dantrolene produced, in contrast to BoNT-A, more motor impairment than analgesia. Paclitaxel treatment resulted in a peripheral neuropathy that affected the two hindpaws. Injection of 20 U/kg (s.p.) Dysport produced a significant antihyperalgesic effect in the injected paw of neuropathic animals 3 days after administration. Unexpectedly, a similar analgesic effect was observed in the contralateral paw. The same results were also observed when Botox was used instead of Dysport. In contrast, a contralateral administration of Dysport in the carrageenan test was ineffective. We conclude that BoNT-A elicits antinociceptive effects independent of the effects on muscular relaxation. Our results suggest that different mechanisms of action are responsible for the effect of BoNT-A in inflammatory and peripheral polyneuropathic rat models.

Preferential uptake of the non steroid anti-inflammatory drug diclofenac into inflamed tissues after a single oral dose in rats

Background

Diclofenac is a nonsteroidal anti-inflammatory drug which is available as prescription (RX) and over-the-counter (OTC) medication for the systemic and topical treatment of painful and inflammatory conditions such as arthritis and back pain. This study was undertaken to investigate the distribution and retention of diclofenac and/or its metabolites in inflamed tissues, using the carrageenan-induced inflammation model and quantitative whole body autoradiography in rats.

Methods

[¹⁴C]diclofenac sodium was administrated as a single 2 mg/kg oral dose 1 h after injection of carrageenan into one front and one hind footpads and subcutaneously into the dorsum of the neck of rats. A control animal received saline injections. Three carrageenan-treated rats and one control rat were sacrificed at 1, 4, 8, and 24 h after [¹⁴C]diclofenac sodium administration (total of 4 rats/time point). The carcasses were immediately snap-frozen and prepared for cryosectioning. Lengthwise whole-body sections (40 μm thick), including all major tissues, were obtained from different levels across the body. The tissue concentrations of total radiolabeled components were determined using quantitative autoradioluminography.

Results

The radioactivity patterns demonstrated that diclofenac and/or its metabolites preferentially distributed into the inflamed tissues. In unharmed tissues the distribution was similar in control and treated animals. The exposure, based on the areas under the tissue concentration versus time (AUC_0-tlast), was 26 and 53 fold higher in the inflamed neck and inflamed footpads of treated animals than in control rats; the exposures in unharmed tissues were similar in the treated and control rats, and the AUC_0-tlast was 17 fold higher in the inflamed paws than in the non inflamed footpads of the carrageenan-treated rats. The higher exposure in the inflamed tissues may be explained partly to the fact that the elimination of total radiolabeled components from inflamed tissues (t_1/2 = 6 h) appeared lower than from the corresponding unharmed tissues (t_1/2 = 2 h).

Conclusion

This animal study demonstrated that diclofenac and/or its metabolites were rapidly and preferentially taken up and retained in inflamed tissues. Although there were theoretical considerations that mildly acidic NSAID may show some preferential distribution in inflamed tissues there was no clear experimental proof for diclofenac until the present study.

Stability and local toxicity evaluation of a liposomal prilocaine formulation

This study reports a physicochemical stability evaluation of a previously reported liposomal prilocaine (PLC(LUV)) formulation (Cereda et al. J. Pharm. Pharmaceut. Sci. 7:235, 2004) before and after steam sterilization as well as its local toxicity evaluation. Prilocaine (PLC) was encapsulated into extruded unilamellar liposomes (LUVs) composed by egg phosphatidylcholine:cholesterol:alfa-tocopherol (4:3:0.07, mole %). Laser light-scattering analysis (p > 0.05) and thiobarbituric acid reaction (p > 0.05) were used to evaluate the liposomes physical (size) and chemical (oxidation) stability, respectively. The prilocaine chemical stability was followed by (1)H-nuclear magnetic resonance. These tests detected no differences on the physicochemical stability of PLC or PLC(LUV), sterilized or not, up to 30 days after preparation (p > 0.05). Finally, the paw edema test and histological analysis of rat oral mucosa were used to assess the possible inflammatory effects of PLC(LUV). PLC(LUV) did not evoke rat paw edema (p > 0.05), and no significant differences were found in histological analysis, when compared to the control groups (p > 0.05). The present work shows that PLC(LUV) is stable for a 30-day period and did not induce significant inflammatory effects both in the paw edema test and in histological analysis, giving supporting evidence for its safety and possible clinical use in dentistry.

COX-2 expression and function in the hyperalgesic response to paw inflammation in mice

Peripheral inflammation and edema are often accompanied by primary and secondary hyperalgesia which are mediated by both peripheral and central mechanisms. The role of cyclooxygenase-2 (COX-2)-mediated prostanoid production in hyperalgesia is a topic of substantial current interest. We have established a murine foot-pad inflammation model in which both pharmacologic and genetic tools can be used to characterize the role of COX-2 in hyperalgesia. Zymosan, an extract from yeast, injected into the plantar surface of the hindpaw induces an edema response and an increase in COX-2 expression in the hindpaw, spinal cord and brain. Zymosan-induced primary hyperalgesia, measured as a decrease in hindpaw withdrawal latency in response to a thermal stimulus, is long-lasting and is not inhibited by pre-treatment with the systemic COX-2 selective inhibitor, parecoxib (20 mg/kg). In contrast, the central component of hyperalgesia, measured as a reduction in tail flick latency in response to heat, is reduced by parecoxib. Zymosan-induced primary hyperalgesia in Cox-2-/- mice is similar to that of their Cox-2+/+ littermate controls. However, the central component of hyperalgesia is substantially reduced in Cox-2-/- versus Cox-2+/+ mice, and returns to baseline values much more rapidly. Thus pharmacological data suggest, and genetic experiments confirm, (i) that primary hyperalgesia in response to zymosan inflammation in the mouse paw is not mediated by COX-2 function and (ii) that COX-2 function plays a major role in the central component of hyperalgesia in this model of inflammation.

Aegiceras corniculatum extract suppresses initial and late phases of inflammation in rat paw and attenuates the production of eicosanoids in rat neutrophils and human platelets

AIM OF THE STUDY

The present study is designed to explore the anti-inflammatory potential of Aegiceras corniculatum Linn. Blanco stems extracts and their mechanism of action against various pro-inflammatory mediators and to validate its traditional use against inflammatory diseases.

MATERIALS AND METHODS

Rat paw edema and peritonitis models were employed for in vivo studies. For in vitro studies human platelets and rat neutrophils were stimulated with Ca(2+)-ionophore A23187 leading to the production of various pro-inflammatory metabolites, i.e., 12-HTT, 12-HETE and LTB(4) and 5-HETE which were quantified by HPLC.

RESULTS

The highly polar methanol extract (100mg/kg) caused approximately 90% reduction in the carrageenan- and prostaglandin E2-induced paw edema in rats. It also caused the inhibition of cycloxygenase-1 metabolite, 12-HHT (IC(50) 41.1+/-1.5microg/ml) with a concomitant rise in 12-lipoxygenase metabolite, 12-HETE in A23187 stimulated human platelets. Conversely, the non-polar hexane extract attenuated (IC(50) 0.36+/-0.12microg/ml) 12-HETE formation with a parallel rise in 12-HHT, thereby displaying a selectivity towards 12-lipoxygenase. Non-polar hexane extract also antagonized the production of 5-lipoxygenase metabolites, i.e., leukotriene B(4) and 5-HETE in the rat neutrophils. Furthermore, ethyl acetate extract inhibited both COX and 5-LOX with a marked decline in the production of 12-HHT (IC(50) 0.08+/-0.002microg/ml) and LTB(4) (IC(50) 0.86+/-0.03microg/ml), respectively. The anti-inflammatory effect of hexane and ethyl acetate extracts was also reflected by the diminution of carrageenan-induced cell infiltration in rat peritoneum. Additionally, plant extracts caused approximately 60% suppression in dextran-induced paw edema implying that they also ameliorate histamine and serotonin release.

CONCLUSION

Hexane, ethyl acetate and methanol extracts derived from Aegiceras corniculatum possess significant anti-inflammatory activity via multiple mechanisms and validate their traditional use against inflammation-related diseases.

Inhibition of MAP kinases and down regulation of TNF-alpha, IL-beta and COX-2 genes by the crude extracts from marine bacteria

Crude ethyl acetate extracts from marine bacterial isolates Staphylococcus arlettae KP2 (GenBank accession No. EU594442) and Planococcus maritimus KP8 (GenBank accession No. EU594443) isolated from Andaman seas were studied for their anti-inflammatory effect by lymphocyte proliferation assay (LPA) employing peripheral blood mononuclear cells (PBMCs). The crude extracts from both the bacteria down regulated the synthesis of inflammatory mediators such as tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and cyclooxygenase-2 (COX-2), besides markedly inhibiting p38 mitogen activated protein (MAP) kinase. These results suggest that the crude ethyl acetate extracts from both the isolates do contain compounds capable of inhibiting inflammation in mitogen induced PBMC and efforts to score potential bioactive molecules from these extracts may prove to be a promising preposition.

Antinociceptive and anti-inflammatory effects of the essential oil from Eremanthus erythropappus leaves

The chemical composition of the essential oil from air-dried leaves of Eremanthus erythropappus was studied. The main compounds were beta-pinene (23.24%), beta-caryophyllene (22.92%), beta-myrcene (10.03%) and germacrene D (9.40%). The essential oil had an LD50 of 2.90 g kg(-1) in mice. Doses of 200 and 400 mg kg(-1) inhibited 10.69% and 27.06% of acetic-acid-induced writhing in mice, respectively. In the formalin-induced nociception test in mice, the essential oil inhibited the first phase of paw licking by 29.13% (400 mg kg(-1)) and the second phase by 32.74% (200 mg kg(-1)) and 37.55% (400 mg kg(-1)). In the hot-plate test in mice, doses of 200 mg kg(-1) and 400 mg kg(-1) significantly increased the reaction time after 30, 60 and 90 min of treatment. Doses of 200 and 400 mg kg(-1) inhibited carrageenan-induced paw oedema in rats by 15.18% and 36.61%, respectively. Doses of 200 and 400 mg kg(-1) administered 4 h before intrapleural injection of carrageenan significantly reduced exudate volume (by 20.20% and 48.70%, respectively) and leucocyte mobilization (by 5.88% and 17.29%, respectively). These results demonstrate that E. erythropappus has analgesic and anti-inflammatory properties, supporting the use of this plant in folk medicine.

Compartmental relaxation and diffusion tensor imaging measurements in vivo in lambda-carrageenan-induced edema in rat skeletal muscle

Integrated diffusion tensor T(2) measurements were made on normal and edematous rat muscle, and the data were fitted with one- and two-compartment models, respectively. Edematous muscle exhibited a short-lived component (T(2) = 28 +/- 6 ms), with diffusion characteristics similar to that of normal muscle, and a long-lived component (T(2) = 96 +/- 27 ms), with greater mean apparent diffusion coefficient (ADC) and lower fractional anisotropy (FA). With this two-component description of diffusion and relaxation, values of ADC and FA estimated with a conventional pulsed-gradient spin-echo sequence will depend on the echo time, relative fraction of short-lived and long-lived water signals, and the intrinsic ADC and FA values within the tissue. On the basis of the relative differences in water diffusion properties between long-lived and short-lived water signals, as well as the similarities between the short-lived component and normal tissue, it is postulated that these two signal components largely reflect intracellular and extracellular water.

Effect of tumour necrosis factor-alpha receptor 1 genetic deletion on carrageenan-induced acute inflammation: a comparison with etanercept

In the present study, we used tumour necrosis factor-alpha receptor 1 knock-out mice (TNF-alphaR1KO) to evaluate an in vivo role of TNF-alphaR1 on the pathogenesis of inflammatory diseases. We used a murine model of carrageenan-induced acute inflammation (pleurisy), a preclinical model of airway inflammation. The data proved that TNF-alphaR1KO were resistant to carrageenan-induced acute inflammation compared with TNF-alpha wild-type mice. TNF-alphaR1KO showed a significant reduction in accumulation of pleural exudate and in the number of inflammatory cells, in lung infiltration of polymorphonuclear leucocytes and lipid peroxidation and showed a decreased production of nitrite/nitrate in pleural exudates. Furthermore, the intensity and degree of the adhesion molecule intercellular adhesion molecule-1 and P-selectin, Fas ligand (FasL), inducible nitric oxide sythase and nitrotyrosine determined by immunohistochemical analysis were reduced markedly in lung tissues from TNF-alphaR1KO at 4 h and 24 h after carrageenan injection. Moreover, TNF-alpha and interleukin-1beta concentrations were reduced in inflamed areas and in pleural exudates from TNF-alphaR1KO. To support the results generated using pleural inflammation, carrageenan-induced paw oedema models were also performed. In order to elucidate whether the observed anti-inflammatory effects were related to the inhibition of TNF-alpha, we also investigated the effect of etanercept, a TNF-alpha soluble receptor construct, on carrageenan-induced pleurisy. The treatment with etanercept (5 mg/kg subcutaneously 2 h before the carrageenan injection) reduces markedly both laboratory and histological signs of carrageenan-induced pleurisy. Our results showed that administration of etanercept resulted in the same outcome as that of deletion of the TNF-alphaR1 receptor, adding a new insight to TNF-alpha as an excellent target by therapeutic applications.

In vivo anti-inflammatory and analgesic activities of a purified saponin fraction derived from the root of Ilex pubescens

The root of Ilex pubescens (Mao-Dong-Qing in Chinese, MDQ) has been commonly used for treatment of cardiovascular and inflammatory diseases in the Chinese medical system. The current studies aimed to investigate the anti-inflammatory and analgesic effects as well as the underlying mechanisms of a purified saponin fraction (PSF) derived from MDQ. PSF was found to significantly suppress the paw edema of rats induced by histamine given intraperitoneally at dosages ranging from 12.5-100 mg/kg. Meanwhile, PSF given orally at dosages of 200 and 100 mg/kg significantly inhibited acetic acid-induced abdominal writhing response of mice and prolonged the time required for mouse tail flick after exposure to a source of radiant heat. The mechanistic studies showed that cyclooxygenase-2 (COX-2) protein expression in carrageenan-injected paw tissues of rats was markedly attenuated by intraperitoneal injection of PSF at dosages of 12.5 to 100 mg/kg. PSF could also markedly inhibit production of proinflammatory cytokines, especially IL-1 beta, IL-6 and TNF-alpha, but enhance production of anti-inflammatory cytokines of IL-4 and IL-10 in the carrageenan-injected paw tissues in rats. These effects resulted in an overall attenuation of the ratio of proinflammatory/anti-inflammatory cytokines and, ultimately suppression of the paw edema. In conclusion, the current study has demonstrated the in vivo anti-inflammatory and analgesic effects of PSF, and suggested that the molecular mechanisms might be associated with inhibition of the elevated expression of COX-2 protein and the overproduction of the proinflammatory cytokines, as well as augmentation of the anti-inflammatory cytokines IL-4 and IL-10 in the carrageenan-injected paw tissues of rats.

Diclofenac attenuates the regional effect of lambda-carrageenan on blood-brain barrier function and cytoarchitecture

The microenvironment of the brain requires tight regulation for proper neuronal function. Protecting the central nervous system (CNS) from the varying concentrations of ions, proteins, and toxins in the periphery is the dynamically regulated blood-brain barrier (BBB). Recent studies have demonstrated significant modulation of the BBB in a number of diseases and physiological states, including pain. This study expands on previous explorations of acute and chronic pain-induced effects on the function and molecular cytoarchitecture of the barrier. It describes the role of cyclooxygenase (COX) up-regulation by blocking with diclofenac (30 mg/kg, i.p.), and it examines the variation in BBB regulation through various brain regions. Edema and hyperalgesia were induced by lambda-carrageenan and attenuated by the additional administration of diclofenac. Examination of unidirectional [14C]sucrose permeability with multitime in situ perfusion studies demonstrated that lambda-carrageenan significantly increased cerebral permeability and decreased brainstem permeability. There were no significant changes in any of the other brain regions examined. These permeability changes correlated with up- and down-regulation of the tight junction (TJ) protein claudin-5 in the cerebrum and brainstem, respectively. Diclofenac administration attenuated the cerebral permeability uptake as well as the claudin-5 up-regulation. In addition, diclofenac reversed the lowered permeability in the brainstem, but it did not attenuate TJ protein expression. These studies demonstrate the complex regulation of the BBB occurring during inflammatory pain and the role of COX in this process. An understanding of BBB regulation during pain states is critically important for pharmacotherapy, and it holds great promise for new therapies to treat central nervous system pathologies.

Role of interleukin-6 in chronic muscle hyperalgesic priming

After recovery from acute muscle pain even minor subsequent muscle use can initiate recurrence of the same mechanical hyperalgesia months or years after the initial injury. We have recently developed a model of this chronic latent hyperalgesia in the rat. In this study, we have examined the possibility that interleukin-6 (IL-6), an inflammatory mediator produced during acute muscle inflammation, can mediate the production of this chronic latent hyperalgesic state in which subsequent exposure to inflammatory mediators produces a markedly prolonged mechanical hyperalgesia. We now report that i.m. injection of IL-6 produced mechanical hyperalgesia, lasting several hours, that was prevented by intrathecal injection of antisense to glycoprotein 130 (gp130), an IL-6 receptor subunit. Furthermore, following complete recovery from i.m. IL-6-induced hyperalgesia, i.m. prostaglandin E(2) produced a mechanical hyperalgesia that was remarkably prolonged compared with naïve controls, indicating the presence of chronic latent hyperalgesia. This ability of IL-6 to produce chronic latent hyperalgesia was prevented by intrathecal administration of antisense for gp130. Furthermore, gp130 antisense also prevented chronic latent hyperalgesia produced by i.m. injection of the inflammogen, carrageenan. These results identify a role for IL-6 in acute inflammatory muscle pain and as a potential target against which therapies might be directed to treat chronic muscle pain.

Peroxisome proliferator-activated receptor-alpha contributes to the anti-inflammatory activity of glucocorticoids

Glucocorticoids (GCs) are effective anti-inflammatory agents widely used in the therapeutic approach to treatment of acute and chronic inflammatory diseases. Previous results suggest that peroxisome proliferator-activated receptor-alpha (PPAR-alpha), an intracellular transcription factor activated by fatty acids, plays a role in the control of inflammation. With the aim of characterizing the role of PPAR-alpha in GC-mediated anti-inflammatory activity, we tested the efficacy of dexamethasone (DEX), a synthetic GC specific for glucocorticoid receptor, in an experimental model of lung inflammation, carrageenan-induced pleurisy, comparing mice lacking PPAR-alpha (PPAR-alphaKO) with wild-type (WT) mice. We also tested the possible synergism of combined treatment with DEX and clofibrate, a PPAR-alpha agonist. Results indicate that DEX-mediated anti-inflammatory activity is weakened in PPAR-alphaKO mice compared with WT controls, and that is increased in WT mice when combined with PPAR-alpha agonist treatment. In particular, DEX was less effective in PPAR-alphaKO, compared with WT mice, as evaluated by inhibition of NF-kappaB, of TNF-alpha production, of cell migration, of cycloxygenase-2 (COX-2) and inducible nitric-oxide synthase activation. Interestingly enough, macrophages from PPAR-alphaKO were less susceptible to DEX-induced COX-2 inhibition in vitro compared with WT mice. However, PPAR-alpha transfection in PPAR-alphaKO macrophages, with consequent receptor expression, resulted in reconstitution of susceptibility to DEX-induced COX-2 inhibition to levels comparable with that obtained in WT macrophages. It is noteworthy that the DEX effect on macrophages in vitro was significantly increased in WT cells when combined with PPAR-alpha agonist treatment. These results indicate that PPAR-alpha can contribute to the anti-inflammatory activity of GCs.

Effect of prostanoid EP4 receptor antagonist, CJ-042,794, in rat models of pain and inflammation

Recent study suggests that the proinflammatory and nociceptive effects of prostaglandin E(2) are mediated by prostanoid receptor subtype EP(4) and prostanoid EP(4) receptor may be a potential target for the treatment of inflammatory pain. Here we describe pharmacological characterization of a novel prostanoid EP(4) receptor antagonist, CJ-042,794 (4-{(1S)-1-[({5-chloro-2-[(4-fluorophenyl) oxy] phenyl} carbonyl) amino] ethyl} benzoic acid) in comparison with piroxicam (non-steroidal anti-inflammatory drug) or rofecoxib (cyclooxygenase-2 inhibitor). CJ-042,794 competitively antagonized cAMP accumulation with a pA(2) value of 8.7 in HEK293 cells overexpressing rat prostanoid EP(4) receptors. Orally administered CJ-042,794 dose-dependently inhibited carrageenan-induced mechanical hyperalgesia with an ED(50) value of 4.7 mg/kg (11 micromol/kg) and its maximal activity was somewhat less effective than that of 10 mg/kg piroxicam (30 micromol/kg p.o.). When CJ-042,794 and rofecoxib were administered to adjuvant-induced arthritis rats on Days 12-22 twice daily, both compounds reversed paw swelling to normal levels. These results suggest that a pharmacological blockade of the prostanoid EP(4) receptor may represent a new therapeutic strategy in signs and symptomatic relief of osteoarthritis and/or rheumatoid arthritis.

Inducible nitric oxide synthase and cyclooxygenase-2 participate in anti-inflammatory and analgesic effects of the natural marine compound lemnalol from Formosan soft coral Lemnalia cervicorni

Lemnalol (8-isopropyl-5-methyl-4-methylene-decahydro-1,5-cyclo-naphthalen-3-ol) is a natural compound isolated from the marine soft coral Lemnalia cervicorni. In the present study, the anti-inflammatory and anti-nociceptive properties of lemnalol were investigated in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and carrageenan-injected rats, respectively. Our results demonstrate that lemnalol significantly inhibited the expression of the pro-inflammatory proteins, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), in LPS-stimulated RAW 264.7 cells. An in vivo inflammation model was induced by intraplantar injection of carrageenan into rat hind paws. An intramuscular injection of lemnalol (15 mg/kg) 10 min before carrageenan injection resulted in significant inhibition of carrageenan-induced rat paw edema and thermal hyperalgesia behavior. Western blot experiments revealed that the carrageenan-induced expression of iNOS and COX-2 in paw tissue was significantly down-regulated by lemnalol. Moreover, post-intrathecal injection of lemnalol produced a dose-dependent anti-nociceptive effect in carrageenan-injected rats (1 and 5 microg). The present results indicate that the marine-derived compound lemnalol had anti-inflammatory and analgesic effects in LPS-stimulated RAW 264.7 cells and carrageenan-injected rats, respectively. In addition, inhibition of elevated iNOS and COX-2 protein expression as well as neurophil infiltration of carrageenan-injected paws may be involved in the beneficial effects of lemnalol.

Celecoxib after the onset of reperfusion reduces apoptosis in the amygdala

Reperfused myocardial infarction induces an inflammatory response that is responsible for local and systemic alterations. Among these, apoptosis observed in the amygdala following myocardial infarction has been pointed out as a consequence of such an inflammatory process. We hypothesized that inhibition of the inducible inflammatory enzyme Cox-2 during the reperfusion period may attenuate the apoptotic process in the amygdala. Anaesthetized rats were subjected to left anterior descending coronary artery occlusion for 40 min, followed by reperfusion. The Cox-2 antagonist Celecoxib (3 mg/kg i.p.) was administered 10 min after the onset of the reperfusion period. After 72 h of reperfusion, infarct size was determined and the lateral and medial amygdala were dissected from the brain. Infarct size was similar between untreated and Celecoxib-treated animals (40-45% of the area at risk). Cox-2 expression was significantly reduced in both parts of the amygdala in the Celecoxib group. Apoptosis regression was observed in the amygdala of the Celecoxib group as shown by decreased number of TUNEL positive cells and by decreased of caspase-3 activation. Bax/Bcl-2 ratio was not significantly altered by Celecoxib while Akt activation was increased in the lateral amygdala but not in the medial amygdala. This data indicates that inhibition of Cox-2 by Celecoxib is associated with regression of apoptosis in the amygdala following myocardial infarction.

Analgesic and anti-inflammatory activities of aqueous extract from Glycine tomentella root in mice

In the present study, we have investigated the analgesic effect of the aqueous extract of the root of Glycine tomentella (AGT) using models of acetic acid-induced writhing response and formalin test, the anti-inflammatory effect of AGT using model of lambda-carrageenan-induced paw edema. In order to investigate the anti-inflammatory mechanism of AGT, we have detected the activities of glutathione peroxidase (GPx) and glutathione reductase (GRx) in the liver and the levels of malondialdehyde (MDA) and NO in the edema paw. In the analgesic test, AGT (0.5 and 1.0 g/kg) decreased the acetic acid-induced writhing response and the licking time on the late phase in the formalin test. In the anti-inflammatory test, AGT (0.5 and 1.0 g/kg) decreased the paw edema at the third, fourth, fifth and sixth hour after lambda-carrageenan administration, and increased the activities of SOD, GPx and GRx in the liver tissue and decreased the MDA level in the edema paw at the third hour after lambda-carrageenan injection. However, AGT could not affect the NO level which induced by lambda-carrageenan. These results suggested that AGT possessed analgesic and anti-inflammatory effects. The anti-inflammatory mechanism of AGT might be related to the decrease in the level of MDA in the edema paw via increasing the activities of SOD, GPx and GRx in the liver.

Anti-inflammatory effects of compounds alpha-humulene and (−)-trans-caryophyllene isolated from the essential oil of Cordia verbenacea

This study evaluated the anti-inflammatory properties of two sesquiterpenes isolated from Cordia verbenacea's essential oil, alpha-humulene and (-)-trans-caryophyllene. Our results revealed that oral treatment with both compounds displayed marked inhibitory effects in different inflammatory experimental models in mice and rats. alpha-humulene and (-)-trans-caryophyllene were effective in reducing platelet activating factor-, bradykinin- and ovoalbumin-induced mouse paw oedema, while only alpha-humulene was able to diminish the oedema formation caused by histamine injection. Also, both compounds had important inhibitory effects on the mouse and rat carrageenan-induced paw oedema. Systemic treatment with alpha-humulene largely prevented both tumor necrosis factor-alpha (TNFalpha) and interleukin-1beta (IL-1beta) generation in carrageenan-injected rats, whereas (-)-trans-caryophyllene diminished only TNFalpha release. Furthermore, both compounds reduced the production of prostaglandin E(2) (PGE(2)), as well as inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) expression, induced by the intraplantar injection of carrageenan in rats. The anti-inflammatory effects of alpha-humulene and (-)-trans-caryophyllene were comparable to those observed in dexamethasone-treated animals, used as positive control drug. All these findings indicate that alpha-humulene and (-)-trans-caryophyllene, derived from the essential oil of C. verbenacea, might represent important tools for the management and/or treatment of inflammatory diseases.

Enhanced synthesis of proinflammatory cytokines by vulvar vestibular fibroblasts: implications for vulvar vestibulitis

OBJECTIVE

The objective of the study was to determine whether vestibular fibroblasts from vulvar vestibulitis (VVS) patients produce higher proinflammatory cytokine levels when provoked with Candida albicans (yeast) and alpha-melanocyte-stimulating hormone (alpha-MSH) in vitro.

STUDY DESIGN

Twenty anatomically defined fibroblast strains from patients and age-matched controls were stimulated with 5 regimens: no stimulus, alpha-MSH, heat-killed yeast, alpha-MSH plus yeast, and interleukin (IL)-1beta. Supernatant products included the following: granulocyte macrophage colony-stimulating factor, interferon-gamma, IL-10, IL-12, IL-1beta, IL-2, IL-4, IL-6, IL-8, and tumor necrosis factor-alpha were assayed.

RESULTS

Coincubation with alpha-MSH plus yeast significantly increased IL-6 (3-fold) and IL-8 (greater than 40-fold) production in patients and controls. Vestibular fibroblast exceeded external vulvar fibroblast production of IL-1beta, IL-6, and IL-8 following yeast alone and alpha-MSH plus yeast stimuli in patients and controls. Substratified by anatomic origin, vestibular fibroblasts from VVS patients produced the highest relative levels of IL-1beta, IL-6, and IL-8 at baseline and following the yeast-alone regimen.

CONCLUSION

Localized pain of VVS may results from regionally elevated cytokines produced by vulvar vestibule-specific fibroblasts.

Anti-inflammatory and anti-allergic properties of the essential oil and active compounds from Cordia verbenacea

The anti-inflammatory and anti-allergic effects of the essential oil of Cordia verbenacea (Boraginaceae) and some of its active compounds were evaluated. Systemic treatment with the essential oil of Cordia verbenacea (300-600mg/kg, p.o.) reduced carrageenan-induced rat paw oedema, myeloperoxidase activity and the mouse oedema elicited by carrageenan, bradykinin, substance P, histamine and platelet-activating factor. It also prevented carrageenan-evoked exudation and the neutrophil influx to the rat pleura and the neutrophil migration into carrageenan-stimulated mouse air pouches. Moreover, Cordia verbenacea oil inhibited the oedema caused by Apis mellifera venom or ovalbumin in sensitized rats and ovalbumin-evoked allergic pleurisy. The essential oil significantly decreased TNFalpha, without affecting IL-1beta production, in carrageenan-injected rat paws. Neither the PGE(2) formation after intrapleural injection of carrageenan nor the COX-1 or COX-2 activities in vitro were affected by the essential oil. Of high interest, the paw edema induced by carrageenan in mice was markedly inhibited by both sesquiterpenic compounds obtained from the essential oil: alpha-humulene and trans-caryophyllene (50mg/kg, p.o.). Collectively, the present results showed marked anti-inflammatory effects for the essential oil of Cordia verbenacea and some active compounds, probably by interfering with TNFalpha production. Cordia verbenacea essential oil or its constituents might represent new therapeutic options for the treatment of inflammatory diseases.

Antipyretic analgesics: nonsteroidal antiinflammatory drugs, selective COX-2 inhibitors, paracetamol and pyrazolinones

Antipyretic analgesics are a group of heterogeneous substances including acidic (nonsteroidal antiinflammatory drugs, NSAIDs) and nonacidic (paracetamol, pyrazolinones) drugs. Moreover, various selective cyclooxygenase-2 (COX-2) inhibitors with improved gastrointestinal tolerability as compared with conventional NSAIDs have been established for symptomatic pain treatment in recent years. The present review summarizes the pharmacology of all of these drugs with particular emphasis on their rational use based on the diverse pharmacokinetic characteristics and adverse drug reaction profiles. Referring to the current debate, potential mechanisms underlying cardiovascular side effects associated with long-term use of COX inhibitors are discussed.

Muscle contraction accelerates IL-6 mRNA expression in the rat masseter muscle

OBJECTIVE

This study was conducted to determine if interleukin-6 (IL-6) and interleukin-1beta (IL-1beta) mRNA expression increase in response to muscle contraction caused by repetitive electrical stimulation of the rat masseter muscle.

METHODS

Male Wistar rats weighing 140-160 g were divided randomly into the following three groups: electrical stimulation (ES) group (n=21), carrageenan injection (CI) group (n=24), and ES under dantrolene sodium (muscle relaxant) injection (ESDI) group (n=7). ES or CI was done to the left masseter; and mock ES or mock CI to the right. Muscle tissues on both sides were sampled for total RNA isolation. Real-time RT-PCR was performed, with the cyclophilin A (CypA) mRNA level in each sample as an internal control. Mean relative IL-6 (il-6/cypA) and IL-1beta (il-1beta/cypA) mRNA levels were compared between the experimental and mock-treated sides within each group.

RESULTS

Mean IL-6/CypA levels in the ES- or CI-treated muscle significantly increased, without any significant incremental change observed in either mock-treated muscle. Interestingly, the increase in the il-6/cypA level caused by the ES was suppressed by the injection of dantrolene sodium in the ESDI group. Furthermore, the mean il-1beta/cypA level in the CI-treated masseter also significantly increased without any significant incremental change observed in the mock-treated muscle. However, there was no significant difference in the mean il-1beta/cypA levels in the masseter between the ES- and the mock-treated sides.

CONCLUSIONS

These results show that IL-6 mRNA expression in the rat masseter muscle was accelerated by the CI or by repetitive muscle contraction induced by ES. Since the mRNA level of IL-1beta, a well-known proinflammatory cytokine, was not altered by the contraction, the accelerated IL-6 mRNA expression elicited by the muscle contraction does not seem to be related to local inflammation.

Estrogen receptor antagonist fulvestrant (ICI 182,780) inhibits the anti-inflammatory effect of glucocorticoids

The glucocorticoid receptor (GR) and estrogen receptor (ER) play important roles in both physiological and pathological conditions involving cell growth and differentiation, lipolysis, control of glucose metabolism, immunity, and inflammation. In fact, recent studies suggest that 17beta-estradiol, like glucocorticoids, may also have anti-inflammatory properties, even if the molecular mechanisms responsible for these activities have not yet been completely clarified. The present study was designed to gain a better understanding of the possible cross-talk between GR and ER in a model of lung inflammation (carrageenan-induced pleurisy). In particular, we have investigated whether fulvestrant (ICI 182,780), a selective ER-alpha antagonist, is able to attenuate the well known anti-inflammatory effect of dexamethasone (DEX), a synthetic glucocorticoid, in ovariectomized rats. We show that ICI 182,780, a selective ER-alpha antagonist, reverses the anti-inflammatory activity exhibited by DEX. Moreover, the coadministration of ICI 182,780 significantly inhibited the ability of DEX to reduce: 1) the degree of lung injury, 2) the rise in myeloperoxidase activity, 3) the increase of poly-(ADP-ribose) polymerase activity, tumor necrosis factor alpha, and interleukin-1beta levels, 4) inducible nitric-oxide synthase, 5) lipid peroxidation, 6) nitrotyrosine formation, 7) cyclooxygenase expression, and 8) the IkappaB-alpha degradation caused by carrageenan administration. In addition, quantitative PCR shows that DEX down-regulates GR and up-regulates glucocorticoid-induced leucine zipper levels, whereas ICI 182,780 does not counteract these effects. In conclusion, these results suggest that the in vivo anti-inflammatory property of DEX is also related to the ER-alpha.

Anti-edematogenic effects of velutinol A isolated from Mandevilla velutina: evidence for a selective inhibition of kinin B1 receptor-mediated responses

This study assesses the effects of compound velutinol A obtained from M. velutina in the rat paw edema induced by several phlogistic agents. Attempts were made to analyze how velutinol A is able to inhibit kinin B(1) receptor-mediated inflammatory responses. Velutinol A (100 nmol/paw) partially reduced (about 30%) the edema evoked by carrageenan (300 microg/paw). However, velutinol A (100 nmol/paw) failed to affect the edema induced by histamine (200 nmol/paw), substance P (30 nmol/paw), PAF (10 nmol/paw) or BK (3 nmol/paw). Interestingly, the edema caused by the selective kinin B(1) receptor agonist des-Arg(9)-BK (100 nmol/paw) in animals pre-treated with PAF or LPS was significantly inhibited by velutinol A (100 nmol/paw) (48 and 46%, respectively). A similar inhibition of des-Arg(9)-BK-induced edema after pre-treatment with PAF was obtained with the non-peptidic and selective B(1) receptor antagonist SSR 240612 (60 nmol/paw) (46%). In addition, the systemic administration of velutinol A (10 mg/kg, i.p.) or SSR 240612 (1 mg/kg, i.p.) also caused a significant reduction of des-Arg(9)-BK (100 nmol/paw)-induced edema in PAF-treated rats (51 and 43%, respectively). The results provide convincing evidence that velutinol A selectively blocks the edema responses mediated by B(1) receptor activation in vivo. This compound might represent a new non-peptidic and selective antagonist for kinin B(1) receptors.

Antiinflammatory activity of Polygala japonica extract

The antiinflammatory activity of the aqueous extract of Polygala japonica (AEPJ) was investigated in mice and rats to find the pharmacological basis for its ethnomedical use. The extract produced a significant inhibition of peritoneal and cutaneous vascular permeability induced by acetic acid and histamine, respectively and ear swelling induced by picryl chloride in mice at the dose of 25.0 mg/kg. Moreover, the extract markedly inhibited footpad edema induced by histamine in rats, and decreased prostaglandin E(2) (PGE(2)) content in carrageenan-induced air-pouch at doses of 12.5 and 6.25 mg/kg respectively.

The role of the peroxisome proliferator-activated receptor-alpha (PPAR-alpha) in the regulation of acute inflammation

The peroxisome proliferator-activated receptor-alpha (PPAR-alpha) is a member of the nuclear receptor superfamily of ligand-dependent transcription factors related to retinoid, steroid, and thyroid hormone receptors. The aim of the present study was to evaluate the role of the PPAR-alpha receptor on the development of acute inflammation. To address this question, we used two animal models of acute inflammation (carrageenan-induced paw edema and carrageenan-induced pleurisy). We report here that when compared with PPAR-alpha wild-type mice, PPAR-alpha knockout mice (PPAR-alphaKO) mice experienced a higher rate of the extent and severity when subjected to carrageenan injection in the paw edema model or to carrageenan administration in the pleurisy model. In particular, the absence of a functional PPAR-alpha gene in PPAR-alphaKO mice resulted in a significant augmentation of various inflammatory parameters (e.g., enhancement of paw edema, pleural exudate formation, mononuclear cell infiltration, and histological injury) in vivo. Furthermore, the absence of a functional PPAR-alpha gene enhanced the staining (immunohistochemistry) for FAS ligand in the paw and in the lung and the expression of tumor necrosis factor alpha and interleukin-1beta in the lungs of carrageenan-treated mice. In conclusion, the increased inflammatory response observed in PPAR-alphaKO mice strongly suggests that a PPAR-alpha pathway modulates the degree of acute inflammation in the mice.

Evaluation of the Anti-inflammatory, Analgesic and Antipyretic Activities of the Natural Polyphenol Chlorogenic Acid

Phenolic compounds are numerous and ubiquitous in the plant kingdom, being particularly present in health-promoting foods. Epidemiological evidences suggest that the consumption of polyphenol-rich foods reduces the incidence of cancer, coronary heart disease and inflammation. Chlorogenic acid (CGA) is one of the most abundant polyphenol compounds in human diet. Data obtained from in vivo and in vitro experiments show that CGA mostly presents antioxidant and anti-carcinogenic activities. However, the effects of CGA on the inflammatory reaction and on the related pain and fever processes have been explored less so far. Therefore, this study was designed to evaluate the anti-inflammatory, antinociceptive and antipyretic activities of CGA in rats. In comparison to control, CGA at doses 50 and 100 mg/kg inhibited carrageenin-induced paw edema beginning at the 2nd hour of the experimental procedure. Furthermore, at doses 50 and 100 mg/kg CGA also inhibited the number of flinches in the late phase of formalin-induced pain test. Such activities may be derived from the inhibitory action of CGA in the peripheral synthesis/release of inflammatory mediators involved in these responses. On the other hand, even at the highest tested dose (200 mg/kg), CGA did not inhibit the febrile response induced by lipopolysaccharide (LPS) in rats. Additional experiments are necessary in order to clarify the true target for the anti-inflammatory and analgesic effects of CGA.

Selective in vivo anti-inflammatory action of the galactolipid monogalactosyldiacylglycerol

The thermophilic blue-green alga ETS-05 colonises the therapeutic thermal muds of Abano and Montegrotto, Italy. Following the isolation, purification and identification of monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulphoquinovosyldiacylglycerol (SQDG) and phosphatidylglycerol from ETS-05, we here examine their in vivo anti-inflammatory activities. MGDG, DGDG and SQDG inhibit croton-oil-induced ear oedema in the mouse in a dose-dependent manner. Inhibition by MGDG is greater than that of the reference drug, betamethasone 17,21-dipropionate, and is largely abrogated following acyl group saturation. SQDG is the least potent of these glycoglycerolipids, and shows an early transient effect. In the in vivo carrageenan-induced paw oedema model in the mouse, the inhibitory effects are again dose dependent, with an enhanced efficacy of MGDG over DGDG, SQDG and the reference drug, indomethacin. These compounds are all less toxic than indomethacin. The selective and enhanced inhibitory effects of MGDG over DGDG indicate the mechanisms behind these in vivo anti-inflammatory actions.