Anti-inflammatory Effect of Piperine in Adjuvant-Induced Arthritic Rats—a Biochemical Approach

The present study was undertaken to investigate the anti-inflammatory effect of piperine against adjuvant-induced arthritis in rats, an experimental model for rheumatoid arthritis and compared it with that of the non-steroidal anti-inflammatory drug indomethacin. Administration of heat-killed Mycobacterium tuberculosis (0. 1 ml) intradermally into the right hind paw of rats resulted in increased paw volume, lysosomal enzymes, glycoproteins and tissue marker enzymes and decreased body weight. However, these changes were reverted to near normal levels upon piperine (30 mg/kg body weight, i.p.) treatment. Histopathological analysis of joints also revealed that synovial hyperplasia and mononuclear infiltration observed in arthritic rats were alleviated by piperine. Thus, the present study clearly indicated that piperine possesses promising anti-inflammatory effect against adjuvant-induced arthritis by suppressing inflammation and cartilage destruction.     

The effects of Enterococcus faecium and selenium on methotrexate treatment in rat adjuvant-induced arthritis

The effects of probiotic bacteria Enterococcus faecium (EF) and selenium were studied on methotrexate (MTX) treatment in rats with adjuvant arthritis (AA). Arthritic rats were preventive treated orally with the following substances: lyophilized EF (15mg/kg/day, 5 days a week); sodium selenite pentahydrate (SSe, 0.050mg/kg containing 0.015 mg/kg selenium, 5 days a week); MTX (0.6 mg/kg/week), and their combinations for the period of 50 days from adjuvant application. Levels of serum albumin, serum nitrite/nitrate concentrations, hind paw swelling, arthrogram scores, whole body bone mineral density (BMD), and bone erosions were evaluated as markers of inflammation and destructive changes associated with arthritis. Long-term preventive treatment with low-dose MTX significantly inhibited the markers of both inflammation and arthritis. EF or SSe when administered singly or in combination had no significant effect on given parameters in arthritic rats. EF but not SSe potentiated the beneficial effects of MTX, which resulted in a more significant reduction of hind paw swelling, arthrogram scores and whole body BMD decrease. EF had a tendency to improve also the effect of MTX on serum albumin and nitrite/nitrate concentrations. Our results indicate that EF may increase the preventive effect of MTX treatment in rat AA by improving its anti-inflammatory and anti-arthritic effects.     

Blockade of interleukin‐6 receptor enhances the anti‐arthritic effect of glucocorticoids without decreasing bone mineral density in mice with collagen‐induced arthritis

In a mouse arthritis model, we investigated whether interleukin‐6 receptor (IL‐6R) blockade would enhance the anti‐arthritic effect of glucocorticoids (GCs). DBA/1J mice were immunized with type II collagen (CII), and were treated with prednisolone (PSL) and/or anti‐mouse IL‐6R antibody (MR16‐1). Also, the effects of IL‐6 on gene expression and the nuclear translocation of glucocorticoid receptors (GRs) were examined in cultured cells treated with dexamethasone (DEX). PSL reduced the arthritis score dose‐dependently in the collagen‐induced arthritis (CIA) mouse model. The arthritis score in the PSL (3 mg/kg) + MR16‐1 group was lower than in the PSL (3 mg/kg) group, and at the same level as in the PSL (6 mg/kg) group. Lumbar vertebra bone mineral density (BMD) was decreased significantly in CIA mice and was higher in the PSL (3 mg/kg) + MR16‐1 group than in the PSL (6 mg/kg) group. In the in‐vitro synovial cells, IL‐6 pretreatment attenuated the inhibitory effect of DEX on cyclooxygenase (COX)‐2 expression and inhibited the nuclear translocation of GR induced by DEX. In contrast, in MC3T3‐E1 osteoblastic cells, IL‐6 pretreatment exacerbated the decrease in expression of osteocalcin and the increase in expression of receptor activator of nuclear factor kappa‐B ligand (RANKL) by DEX. We demonstrated that IL‐6 signalling blockade by an anti‐IL‐6R antibody can augment the anti‐arthritic effect of GCs and inhibit the bone loss they cause.     

The effect of dexamethasone-21-acetate on meal size, meal frequency and macronutrient self-selection in rats

In Experiment 1, the measurement of 24-hour food intake in two rats showed that treatment with dexamethasone-21-acetate (DEX) (0.5 mg/kg IP) produced a decrease in body weight which was at least partially due to a decrease in food intake (both meal frequency and meal size). In Experiment 2, the daily intake of three macronutrient sources was measured. These data showed that treatment with DEX (0.5 and 1.0 mg/kg IP) led to an acute increase in protein intake, a sustained decrease in fat intake and no change in carbohydrate consumption. We suggest that this change in macronutrient selection may be an adaptive response which serves to ameliorate some of the effects of DEX treatment.     

Development of a rapid screen for detecting and differentiating immunomodulatory vs. anti-inflammatory compounds in rats

Polyarthritis can be induced in rats using a synthetic adjuvant, N,N-dioctyldecyl-N, N-bis(2-hydroxyethyl) propanediamine (LA) suspended in oil. The disease is morphologically indistinguishable from the classic adjuvant arthritis induced by Freund's complete adjuvant (FCA). LA injection (7.5 mg/animal) consistently induced paw swelling, splenomegaly and fibrinogen level increases at certain time points. Studies evaluating various protocols and parameters determined that a 15 day assay where agents administered from days 9 through 13, would differentiate immunomodulatory and anti-inflammatory compounds. Parameters utilized were body weight, paw volumes, spleen weights, and fibrinogen levels. Immunomodulatory agents reduce paw swelling, splenomegaly and in some cases fibrinogen levels. NSAIDS reduce paw swelling,increase splenomegaly and have no effect on fibrinogen levels. These results indicate that compounds active in the traditional FCA assay can be detected and differentiated with respect to anti-inflammatory vs. immunomodulatory activity in a rapid screen.     

Anti-inflammatory activities of Aller-7, a novel polyherbal formulation for allergic rhinitis

Allergic rhinitis is an immunological disorder and an inflammatory response of nasal mucosal membranes. Allergic rhinitis, a state of hypersensitivity, occurs when the body overreacts to a substance such as pollens or dust. A novel, safe polyherbal formulation (Aller-7/NR-A2) has been developed for the treatment of allergic rhinitis using a unique combination of extracts from seven medicinal plants including Phyllanthus emblica, Terminalia chebula, Terminalia bellerica, Albizia lebbeck, Piper nigrum, Zingiber officinale and Piper longum. Since inflammation is an integral mechanistic component of allergy, the present study aimed to determine the anti-inflammatory activity of Aller-7 in various in vivo models. The efficacy of Aller-7 was investigated in compound 48/80-induced paw edema both in Balb/c mice and Swiss Albino mice, carrageenan-induced paw edema in Wistar Albino rats and Freund's adjuvant-induced arthritis in Wistar Albino rats. The trypsin inhibitory activity of Aller-7 was also determined and compared with ovomucoid. At a dose of 250 mg/kg, Aller-7 demonstrated 62.55% inhibition against compound 48/80-induced paw edema in Balb/c mice, while under the same conditions prednisolone at an oral dose of 14 mg/kg exhibited 44.7% inhibition. Aller-7 significantly inhibited compound 48/80-induced paw edema at all three doses of 175, 225 or 275 mg/kg in Swiss Albino mice, while the most potent effect was observed at 225 mg/kg. Aller-7 (120 mg/kg, p.o.) demonstrated 31.3% inhibition against carrageenan-induced acute inflammation in Wistar Albino rats, while ibuprofen (50 mg/kg, p.o.) exerted 68.1% inhibition. Aller-7 also exhibited a dose-dependent (150-350 mg/kg) anti-inflammatory effect against Freund's adjuvant-induced arthritis in Wistar Albino rats and an approximately 63% inhibitory effect was observed at a dose of 350 mg/kg. The trypsin inhibitory activity of Aller-7 was determined, using ovomucoid as a positive control. Ovomucoid and Aller-7 demonstrated IC50 concentrations at 1.5 and 9.0 microg/ml, respectively. These results demonstrate that this novel polyherbal formulation is a potent anti-inflammatory agent that can ameliorate the symptoms of allergic rhinitis.     

Effect of μ-opioids morphine and buprenorphine on the development of adjuvant arthritis in rats

Objective and Design: On the basis that endogenous opioids play a role in the physiological response to inflammation, this study tests the antiarthritic effects of a μ-opioid agonist, morphine and the partial μ-agonist, buprenorphine. Material: Male Lewis rats were used. Treatment: Rats were innoculated subcutaneously with 0.05 ml of Freund's complete adjuvant (5 mg/ml) into the right hind paw to produce adjuvant arthritis. Morphine (either 10 to 60 mg/kg/day s.c. bolus or 60 mg/kg/day s.c. infusion) and buprenorphine (0.65±0.06 mg/kg/day, orally), respectively, were administered for 3 days during the primary inflammatory phase of adjuvant arthritis. Methods: The progression of adjuvant arthritis was monitored every three days by body weight change and hind limb oedema (ipsilateral and contralateral). On day 21 the animals were sacrificed and histology and radiography of the contralateral limb were performed. In rats receiving Freund's adjuvant and no drug treatment, the incidence of arthritis was 89%. Effect was expressed as the pooled severity index (PSI) derived from the arithmetic average of the volume, histology and radiography scores in the contralateral hind limb. Results: Buprenorphine had no effect on experimental arthritis (PSI control vs treated: 242±28 vs 253±28%). In contrast, morphine by subcutaneous injection twice daily (10 to 60 mg/kg/day) but not by subcutaneous infusion (60 mg/kg/day) was found to attenuate the progression of adjuvant arthritis in a dose-dependent manner. This indicates that the anti-arthritic effects of morphine are opioid receptor mediated (ED₅₀, 58±9 mg/kg) and suggests that the local concentration reached effective levels only after subcutaneous injection. It is also possible that the high doses of morphine were anti-inflammatory through effects at the kappa receptor. However, these high doses of morphine produced death in one third of the rats, the calculated lethal dose (LD₅₀, 63±2 mg/kg) being close to the effective dose. Conclusion: Anti-arthritic effects of morphine are opioid receptor mediated but morphine use for this indication is restricted by its adverse effects. accepted by M. J. Parnham     

Relationship of blood markers to disease severity and drug efficacy in rat adjuvant arthritis

Rat adjuvant arthritis (AA) was used as a model to evaluate several blood markers as possible predictive indicators of drug efficacy. AA was induced in Sprague-Dawley rats by the injection of complete Freund's adjuvant into the right hind foot pad. The rats were dosed p.o. from day 18 to day 31 with levamisole (10 mg/kg), indomethacin (1 mg/kg), diclofenac sodium (0.5 & 1 mg/kg), and prinomide (10 & 20 mg/kg). Disease severity was assessed by paw circumference on day 31. The following blood markers were analyzed: hyaluronate by ELISA, prostaglandin E₂ by RIA, ESR by micro-dispette, total PMN by Technicon H-1, and albumin by BCG dye. Blood marker correlation (r) to disease severity was: hyaluronate (0.71), prostaglandin E₂ (0.58), ESR (0.52), PMN (0.58), and albumin (–0.71). The relative rank order of drug efficacy (indomethacin, diclofenac sodium, and prinomide) did not differ using the change in paw circumference (day 31–day 17) or blood markers. Levamisole exacerbated the disease as measured by all the above parameters. Thus, these blood markers provide additional information for the statistical evaluation of drugs in rat adjuvant arthritis.     

Hecogenin exhibits anti-arthritic activity in rats through suppression of pro-inflammatory cytokines in Complete Freund’s adjuvant-induced arthritis

Hecogenin is a steroidal sapogenin isolated from the leaves of Agave genus species that plays an important role in the treatment of a variety of inflammatory diseases. The aim of the present study was to evaluate the anti-arthritic activity of hecogenin in Complete Freund’s adjuvant-induced arthritis in rats. The hecogenin (40?µl of 50?µg/kg, orally) and hecogenin?+?fluticasone (40?µl of 25?µg/kg, each, orally) was tested against Complete Freund’s adjuvant-induced arthritis in rats by evaluating various parameters such as paw volume, arthritic score, joint diameter, spleen weight, thymus weight, haematological and biochemical parameters and pro-inflammatory cytokines. Histopathological and radiological analyzes of ankle joints were also carried out. Treatment of rats with hecogenin and its combination elicited significant reduction in paw edema, arthritic score and joint diameter. Hecogenin and its combination also inhibited joint destruction in histopathological and radiological analyzes of ankle joint. Hecogenin and its combination significantly increased the levels of red blood cells and hemoglobin but decreased the white blood cell count. The anti-arthritic activity was also confirmed with the change in biochemical parameters and myeloperoxidase assay. In the present investigation, hecogenin and its combination prevent destruction of cartilage and protect synovial membrane with improving health status through haematonic properties and down regulation of various cytokines. Hence, hecogenin may be a potential therapeutic candidate for the treatment of rheumatoid arthritis.     

Immunological abnormalities in rats with adjuvant-induced arthritis--II. Effect of antiarthritic therapy on immune function in relation to disease development

The effects of the experimental immunomodulatory agent tilomisole (Wy-18,251; (3-(p-chlorophenyl) thiazolo [3,2-a]benzimidazole-2-acetic acid) on disease development and immune function in rats with adjuvant-induced arthritis was assessed in comparison with indomethacin and levamisole. Daily p.o. administration of tilomisole (100-200 mg/kg/day) to M. butyricum-injected rats significantly reduced both edema and bone erosion in the uninjected paw. Moreover, tilomisole treatment restored to normal the diminished Con A-induced proliferative response and IL 2 synthesis observed in spleen cells from arthritic rats, but had no effect on macrophage IL 1 production. In contrast, levamisole treatment (25 mg/kg/day) of arthritic rats improved splenic immune function but did not influence paw edema or bone erosion. Conversely, indomethacin (1 mg/kg/day) significantly reduced paw edema and bone erosion but did not improve the deficient proliferative response or IL 2 synthesis by "arthritic" spleen cells. These results indicate that tilomisole possesses combined antiinflammatory and immunomodulatory activity in adjuvant-arthritic rats which is distinctly different from the effects of either indomethacin or levamisole. Moreover, these data suggest that tilomisole has potential disease-modifying activity in arthritis, which is currently being more closely examined in clinical trials.     

A High Molecular Weight Protein Extract of Mastobranchus indicus (Mi-64) Having Antiarthritic Activity in Experimental Animals

Mi-64, a high molecular weight protein (130 kDa), obtained from the tissue homogenate of marine polychaete (Mastobranchus indicus) collected from the Indian Sunderban has antiarthritic activity in experimental animals. The FCA-induced arthritis model was developed in Wistar albino rats to evaluate the antiarthritic effects of Mi-64. After FCA induction, the rats were treated with Mi-64 (0.25 and 0.5 mg kg(-1) body weight) for 10 days. We have determined the paw/ankle swellings, urinary hydroxyproline and glucosamine, serum acid and alkaline phosphatases to assess the antiarthritic activity. The levels of interleukin-1 beta (IL-1β), IL-6, cytokine-induced neutrophil chemoattractant-1 (CINC-1), tumor necrosis factor-alpha (TNF-α), and IL-10 were measured by ELISA. Results showed that Mi-64 significantly reduced paw/ankle swellings and restored the urinary hydroxyproline/glucosamine and serum phosphatases. Mi-64 significantly inhibited the overproduction of IL-1β, IL-6, CINC-1, and TNF-α and augmented IL-10 production. The data suggest that Mi-64 produced significant antiarthritic effects that may be mediated by balancing the pro- and anti-inflammatory cytokines.     

Evaluation of analgesic and anti-inflammatory activity of diospyros cordifolia extract

In this study we evaluated the analgesic and anti-inflammatory activities of the methanol extract of stem bark of Diospyros cordifolia (MEDC) Roxb. The analgesic effects of the stem bark of the plant was assessed in mice using the tail-flick method while carrageenan, histamine and dextran induced paw oedema was used to study the antiinflammatory effects in rats. The MEDC exhibited significant (p<0.01) analgesic effects comparable to the reference drug diclofenac sodium. MEDC also was evaluated for its anti-inflammatory potential against carrageenan, histamine and dextran induced rat paw edema. The methanol extract (25 and 50 mg / kg body weight) exhibited significant (p<0.01) activity against all phlogistic agents used in a dose dependent manner. All these effects were compared with reference drug phenylbutazone (100 mg/kg body weight).     

Anti-arthritic properties of FK506 on collagen-induced arthritis in rats

Objective and design:To determine the effect of FK506 (tacrolimus) on paw inflammation, TNF- expression in joint, and bone and cartilage destruction in type II collagen-induced arthritis (CIA) model in rats.Methods:CIA was induced by immunization of female Lewis rats with an emulsion of bovine type II collagen and incomplete Freunds adjuvant. Paw inflammation was assessed by the increase in paw volume. Tumor necrosis factor (TNF) - expression in hind knee joint was assessed by immunohistochemical analysis. Lesions of bone and cartilage were assessed on the basis of histological change in knee joint, radiographic analysis in hind paw, bone mineral density in femora and proteoglycan contents in the cartilage of femoral heads. FK506 at doses of 1, 1.8 and 3.2 mg/kg or its placebo formulation was orally administered to rats for 28 days from the day after immunization (n = 10). Effect of FK506 was compared with that of vehicle (distilled water).Results:FK506 at a dose of 1.8 mg/kg significantly suppressed paw swelling (p < 0.01) and histological change in knee joint (p < 0.05). Tumor necrosis factor (TNF)- was mainly expressed in the region with a marked infiltration of inflammatory cells in the hind knee joint. FK506 (3.2 mg/kg) markedly reduced TNF- expression. FK506 at a dose of 1.8 mg/kg suppressed radiographic changes in hind paw (p < 0.05) and also recovered the decrease in bone mineral density in the femora (p < 0.05). Proteoglycan contents in the cartilage of femoral heads were determined to evaluate the cartilage destruction more quantitatively and found to significantly decrease in CIA rats. FK506 at a dose of 1.8 mg/kg recovered the loss of proteoglycan contents (p < 0.01).Conclusion:These results show that FK506 is effective in suppressing inflammation, TNF- expression in joint, and damage to bone and cartilage in rat CIA, and may be useful in the treatment of rheumatoid arthritis.     

Antiinflammatory Effect of Lipocortin 1 in Experimental Arthritis

The glucocorticoid-induced antiinflammatory protein lipocortin 1 is present in arthritic synovium but its ability to regulate joint inflammation has not previously been studied. We investigated the role of lipocortin 1 in the antiinflammatory activity of glucocorticoids in an acute arthritis model induced by intraarticular injection of carrageenan. Compared to control joints (0.09 ± 0.08 × 10⁶ synovial fluid cell count), carrageenan injected joints exhibited marked infiltration of PMN (10.2 ± 0.7 × 10⁶, p < 0.001). Both intraperitoneal (1.0 mg/kg) and intraarticular administration (5 g) of dexamethasone (DEX) significantly suppressed arthritis severity (p < 0.001 and 0.005, respectively), and the effects of DEX were significantly prevented by intra-articular injection of antilipocortin 1 mAb (p < 0.05). Carrageenan arthritis was also significantly inhibited by intraarticular administration of the N-terminal lipocortin 1 peptide Ac2-26 at doses of 1 or 2 mg/kg (p < 0.01). Intraarticular injection antilipocortin 1 mAb in the absence of DEX also significantly exacerbated arthritis severity (p < 0.005). In vitro treatment of PMN with DEX was associated with significant inhibition of phagocytosis (p < 0.005) and reactive oxygen species (ROS) generation (p < 0.001). Antilipocortin 1 mAb significantly reduced the inhibitory effects of DEX (p < 0.01 and 0.005, respectively). These results demonstrate that lipocortin 1 mediates the effects of exogenous glucocorticoids on neutrophil migration in carrageenan-induced acute arthritis, exerts an endogenous antiinflammatory influence, and mediates glucocorticoid inhibition of neutrophil activation.     

FK506 is superior to methotrexate in therapeutic effects on advanced stage of rat adjuvant-induced arthritis

OBJECTIVE AND DESIGN: The anti-arthritic properties of FK506 were compared with methotrexate (MTX) in established adjuvant-induced arthritis (AIA) in rats. MATERIAL: Female Lewis rats. TREATMENT: Arthritic rats were orally administered with FK506 (1-5.6 mg/kg) and MTX (0.1-1 mg/kg) from days 15-24. METHODS: Arthritis was induced by injection of Mycobacterium tuberculosis into the right hind footpad on day 0. Efficacy was determined on the basis of paw inflammation measured by paw volume and histological change, hyperalgesia and grip strength. Grip strength measurement was employed as an indication of function of paws in arthritic rats. Peripheral white blood cell (WBC) counts and thymus weights were measured, mainly as indicators of toxic side effects. RESULTS: FK506 suppressed paw inflammation and hyperalgesia without toxic effects on WBC and thymus in established AIA. MTX slightly suppressed paw inflammation and hyperalgesia at the highest dose (1 mg/kg). Toxic effects were observed at lower doses than the effective treatment dose with MTX. Grip strength was found to decrease during development of AIA. FK506, but not MTX, treated rats recovered grip strength loss. CONCLUSIONS: The results show that FK506 is more effective and less toxic than MTX in treating established AIA in rats.     

Effect of clodronate on established collagen-induced arthritis in rats

The collagen-induced arthritis model in rats was used to study the effect of disodium clodronate on inflammation and destruction of tarsal, metatarsal, and interphalangeal bones and joints. Female DA rats were immunized with heterologous type II collagen. Fourteen days after immunization, rats with similar scores were assigned to the different experimental groups. They were treated subcutaneously either with saline (controls) or with clodronate at doses of 12.5 and 25 mg/kg/day five times a week for 2 weeks. Clinical signs of arthritis including the severity of paw swelling were assessed weekly. At the time of killing, histological features of the non-decalcified tarsus with tarsal, tarsometatarsal and interphalangeal joints were assessed for inflammatory soft-tissue, articular, and bone changes. All the arthritic control rats developed severe arthritis as shown by the total histological scores of the hindpaw. The treatment with clodronate (25 mg/kg) decreased clinical signs of arthritis, the activity of the collagen-degrading lysosomal enzyme,-N-acetylglucosaminidase, in inflamed hindpaw tissue, serum osteocalcin level and serum cross-linked telopeptide of type I collagen level. Histological evaluation indicated moderate arthritis in 29% of the rats and severe arthritis in 71%. The results show that clodronate given therapeutically to arthritic rats, induced with type II collagen, suppresses the intensity of inflammation and bone lesions in the tibiotarsal and tarsometatarsal regions.     

Opioid systems in the response to inflammatory pain: sustained blockade suggests role of kappa- but not mu-opioid receptors in the modulation of nociception, behaviour and pathology.

One day after intraplantar inoculation of Mycobacterium butyricum into the right hind-paw, unilaterally inflamed and control rats were implanted subcutaneously with osmotic mini-pumps delivering naloxone at 0.16 or 3.0 mg/kg/h or vehicle. As determined three days after implantation, 0.16 mg/kg/h of naloxone completely antagonized the antinociceptive action of the mu-agonist, morphine, but did not affect antinociception evoked by the kappa-agonist, U69,593. In contrast, at 3.0 mg/kg/h, naloxone blocked both morphine- and U69,593-induced antinociception. Thus, 0.16 mg/kg ("low dose") and 3.0 mg/kg ("high dose") of naloxone block mu, or mu- plus kappa-opioid receptors, respectively. Pumps were removed one week following their implantation. Inoculation was associated with a sustained hyperalgesia of the inflamed paw to noxious pressure, and elevation in resting core temperature, a loss of body weight, hypophagia, hypodipsia and a reduction in mobility. These parameters were differentially modified by the high as compared to the low dose of naloxone. Two days following implantation of pumps delivering the high dose of naloxone, the hyperalgesia of the inflamed paw was potentiated: by six days, this effect was lost. Further, one day after removal of pumps yielding the high dose, the inflamed paw showed a normalization of thresholds, that is a "rebound antinociception". One day later, this effect had subsided. In distinction, at no time did the low dose of naloxone modify nociceptive thresholds. The high dose of naloxone enhanced the reduction in body weight and food intake shown by unilaterally inflamed rats whereas the low dose was ineffective. Neither dose affected the reduction in water intake or hypothermia of unilaterally inflamed animals. The high dose of naloxone reduced the mobility of unilaterally inflamed rats whereas the low dose was ineffective. Finally, by 10 days following pump removal, pathology had transferred to the contralateral paw. In rats which had received the high but not the low dose, this transfer was blocked. It is concluded that blockade of kappa-opioid receptors with a high dose of naloxone experts pronounced functional effects in unilaterally inflamed rats. In distinction, selective blockade of mu-receptors with a low dose is ineffective. The changes seen include not only an enhancement of the hyperalgesia of the inflamed tissue, but also an exacerbation of variables (body weight, food intake and motility) which reflect pain states.(ABSTRACT TRUNCATED AT 400 WORDS)     

Anti-Nociceptive and Anti-Inflammatory Activities of Ethanol Extract of Syzygium Aromaticum Flower Bud in Wistar Rats and Mice

The ethanol extracts of Syzygium aromaticum flower bud were tested for anti-nociceptive and anti-inflammatory effects in mice and Wistar rats which were carried out using acetic acid-induced abdominal contractions in mice and formalin-induced hind paw edema in Wistar rats. Three doses of the ethanol extract (50, 100, and 200mg/kg body weight i.p.) were used for both studies. The extract had an LD₅₀ of 565.7 mg/kg body weight intraperitoneally in mice. The extracts produced significant effect (P<0.05) at all the three doses. Similarly, the anti-nociceptive activity produced significant effects (P<0.05) at all the three doses of the extract. The result supports the local use of the plant in painful and inflammatory conditions.     

Effect of the selective COX-2 inhibitors, celecoxib and rofecoxib in rat acute models of inflammation

OBJECTIVE: This study evaluates the action of celecoxib and rofecoxib, two selective cyclooxygenase-2 (COX-2) inhibitors in two acute models of inflammation, carrageenan (Cg)-induced rat pleurisy, and paw oedema formation. MATERIAL: Male Wistar rats (N = 4-10 per group) were used. A fixed volume of PBS or carrageenan was injected into the pleural cavity or into the paw. Furthermore, the myeloperoxidase (MPO) activity and the levels of nitrite/nitrate (NOx), interleukin-1beta (IL-1beta), tumor necrosis factor-a (TNF-a) and PGE2 were also assessed in the paw tissue or in pleural exudate. RESULTS: Dexamethasone (DEX, 0.5 mg kg(-1), s.c., -4 h) and indomethacin (INDO, 3 mg kg(-1), p.o., -1 h) suppressed Cg-induced pleural exudate accumulation by 84 and 77% and inflammatory cell influx by 66 and 47%, respectively. In contrast, celecoxib (CLX, 10 mg kg(-1), p.o., -1 h) or rofecoxib (RFX, 10 mg kg(-1) , p.o., -1 h) only reduced the Cg-induced pleural exudate volume by 44 and 40%, respectively, but had no significant effect over inflammatory cell influx. At the same doses used for pleurisy, DEX, INDO, CLX, RFX and SC-560 (a selective COX-1 inhibitor, 40 mg kg(-1), p.o., -1 h), inhibited the Cg-induced paw oedema by 49, 31, 21, 21 and 17%. DEX, INDO or SC-560 reduced the level of MPO by 71, 78 and 59%, while CLX or RFX produced a small, but significant increase (28 or 16%) in MPO activity. In the rat model of pleurisy, PGE2 levels in cell-free exudates were significantly attenuated by 91, 89, 57 and 65% in animals treated with DEX, INDO, CLX or RFX. In contrast, INDO reduced significantly the whole bloodTXB, synthesis (59%) while DEX and INDO reduced the pleural content of NOx significantly. Treatment of animals with CLX or RFX did not alter the content of pro-inflammatory cytokines IL-1beta or TNF-alpha in the pleural exudate, but CLX reduced IL-1beta levels in the rat paw tissue and RFX increased TNF-alpha in this tissue. CONCLUSION: Together these results provide consistent evidence indicating that the selective COX-2 inhibitors CLX and RFX, in contrast to DEX, INDO or SC-560, despite reducing greatly the Cg-induced pleural exudation, PGE2 content and paw oedema have only partial acute anti-inflammatory properties in two different rat acute models of inflammation.