Nimesulide and diclofenac inhibit lipopolysaccharide-induced hypothermia and tumour necrosis factor-alpha elevation in rats

Nephroprotective effect of silymarin against diclofenac induced renal damage and oxidative stress in male rats

Introduction: Diclofenac (DIC), a phenylacetic acid compound which belongs to nonsteroidal anti-inflammatory drugs (NSAIDs), is generally used for the treatment of various diseases such as rheumatoid arthritis, ankylosing spondylitis, acute muscle pain conditions and osteoarthritis. Overdose of DIC can lead to renal injuries in both experimental animal and human. Our research was done to assess the protective role of silymarin on renal damage induced by DIC in rats. Methods: Thirty-two Wistar rats were assigned to four groups (n=8/group). Group 1 was control group; animals in group 2 were administrated DIC; Groups 3 and 4 administrated DIC plus silymarin with doses of 100 mg/kg and 200 mg/kg, orally (p.o), respectively. Various biochemical, molecular, and histological parameters were evaluated in serum and tissue homogenate. Results: In the second group, the levels of kidney catalase (CAT), vitamin C and superoxide dismutase (SOD) remarkably reduced (P < 0.05) relative to the control group. Also, urea, creatinine (Cr), malondialdehyde (MDA), serum tumor necrosis factor-α (TNF-α) and gene expression of TNF-α in this group were noticeably elevated (P < 0.05) relative to the control group. Treatment with silymarin caused a remarkable elevation (P < 0.05) in vitamin C, SOD, CAT and a remarkable reduction (P < 0.05) in the content of MDA, urea, Cr, TNF-α gene expression and serum TNF-α in comparison with second group. Histological injuries were also ameliorated by silymarin administration. Conclusion: The results confirm that silymarin has an ameliorative role against renal damage and oxidative stress induced by DIC in male rats.

Anti-rheumatoid activity of ethanolic extract of Sesamum indicum seed extract in Freund's complete adjuvant induced arthritis in Wistar albino rats

Sesamum indicum, one of the first recorded plants used for its seeds, is reported to have analgesic, antioxidant, anticancer, anti-obesity as well as hepato and nephro protective activities. The current study evaluated the effects of two doses (400 and 800 mg/kg) of ethanolic extract of S. indicum seeds in Freund's complete adjuvant induced arthritis in rats in comparison with diclofenac and methotrexate by the changes produced in body weight, body temperature, paw volume and spontaneous activity, hemoglobin, erythrocyte sedimentation rate, total white blood cells, red blood cells, Interleukin-6 and Tumor necrosis factor-α as well as joint changes in X-ray and histological changes in joint tissue. Unlike the untreated group, the groups treated with S. indicum showed significant decrease in paw volume, body weight, white blood cell count, erythrocyte sedimentation rate, Interleukin-6 and Tumor necrosis factor-α and an increase in body weight, spontaneous activity, hemoglobin level, and red blood cell count. Histopathological examination showed gross reduction in synovial inflammation and cartilage damage. X-ray revealed significant improvement in joint space. The effect of ethanolic extract of S. indicum was found to be equivalent to methotrexate and greater than diclofenac.

Prostaglandin Transporter OATP2A1/SLCO2A1 Is Essential for Body Temperature Regulation during Fever

Prostaglandin E₂ (PGE₂) in the hypothalamus is a principal mediator of the febrile response. However, the role of organic anion transporting polypeptide 2A1 (OATP2A1/SLCO2A1), a prostaglandin transporter, in facilitating this response is unknown. Here, we investigated the effect of Slco2a1 deficiency on the body core temperature (Tc) and on the PGE₂ concentration in hypothalamus interstitial fluid (C_isf) and CSF (C_csf) of lipopolysaccharide (LPS; 100 μg/kg, i.p.)-treated mice of both sexes. Slco2a1^-/- mice did not develop a febrile response. C_csf was increased in Slco2a1^+/+ and Slco2a1^-/- mice, and C_csf of Slco2a1^-/- mice was well maintained at 5 h after LPS injection (1160 pg/ml) compared with Slco2a1^+/+ mice (316 pg/ml). A microdialysis study revealed that C_isf peaked at 2 h after LPS injection in Slco2a1^+/+ mice (841 pg/ml), whereas the increase in C_isf was negligible in Slco2a1^-/- mice. The PGE₂ plasma concentration in Slco2a1^-/- mice (201 pg/ml) was significantly higher than that in Slco2a1^+/+ mice (54 pg/ml) at 1 h after LPS injection, whereas the two groups showed similar PGE₂ concentrations in the hypothalamus. Strong Oatp2a1 immunoreactivity was observed in F4/80-positive microglia and perivascular cells and in brain capillary endothelial cells. The changes in Tc and C_isf seen in LPS-injected Slco2a1^+/+ mice were partially attenuated in monocyte-/macrophage-specific Slco2a1^-/- (Slco2a1^Fl/Fl/LysM^Cre/+) mice. Thus, OATP2A1 facilitates the LPS-induced febrile response by maintaining a high level of C_isf, possibly by regulating PGE₂ secretion from F4/80-positive glial cells and/or facilitating PGE₂ transport across the blood-brain barrier. These findings suggest that OATP2A1 is a useful therapeutic target for neuroinflammation.SIGNIFICANCE STATEMENT Fever is a physiological response caused by pyrogen-induced release of prostaglandin E₂ (PGE₂) in the hypothalamus, which plays a central role in regulating the set-point of body temperature. However, it is unclear whether the prostaglandin transporter OATP2A1/SLCO2A1 is involved in this response. We show here that LPS-induced fever is associated with increased PGE₂ concentration in hypothalamus interstitial fluid (C_isf), but not in CSF (C_csf), by means of a microdialysis study in global Slco2a1-knock-out mice and monocyte-/macrophage-specific Slco2a1-knock-out mice. The results suggest that OATP2A1 serves as a regulator of C_isf in F4/80-positive glial cells. OATP2A1 was detected immunohistochemically in brain capillary endothelial cells and, therefore, may also play a role in PGE₂ transport across the blood-brain barrier.

The role of nonsteroidal anti-inflammatory drugs intramuscular injection in the development and severity of deep soft tissue infection in mice

The aim of this study was to determine the role of nonsteroidal anti-inflammatory drugs (NSAID) injection on the severity of local infection and the effect on the progression of soft tissue infection (STI).The mouse model of STI with Group A streptococcus (GAS) was developed and treated with diclofenac sodium (DS) intramuscularly. Mice were divided into five groups: administered DS for 48 h before GAS (Group 1), GAS-DS and maintained DS for 48 h (Group 2), DS for 48 h (Group 3), GAS on zero time (Group 4), and control (Group 5). In vitro, a high concentration (40 mg/L) of DS inhibited GAS growth, whereas a lower concentration (0.4 mg/L) was not effective. Sepsis was observed in animals with DS and GAS inoculation (group 1 and 2). Group 4 had statistically significant higher bacterial load than groups 1 and 2. All groups had a higher inflammation rate than the control group. The median of TNF-alpha and mean IL-6 in the groups 1, 2, and 4 was significantly higher than those in the control group. Even if the animals that were treated with DS injection prior to the GAS inoculation had similar inflammation score, similar cytokine levels and low bacterial load in the tissue, they had a rather high rate of sepsis. In conclusion, DS injection prior to bacterial inoculation might predispose to bacteremia and sepsis.

Perioperative diclofenac application during video-assisted thoracic surgery pleurodesis modulates early inflammatory and fibrinolytic processes in an experimental model

BACKGROUND/PURPOSE

It has been substantiated that the quality of pleurodesis is reduced when non-steroidal anti-inflammatory drugs (NSAIDs) are used perioperatively. The effects of NSAID administration on the early inflammatory and fibrinolytic processes after mechanical pleurodesis were investigated in an established pig model.

METHODS

Left-sided mechanical pleural abrasion was performed on 24 pigs assigned to either an NSAID or a control group. Pleural fluid and blood samples were analysed over a 24-hour period. Histological evaluation of neutrophil influx at the site of pleural abrasion was performed.

RESULTS

The volume of pleural effusion was significantly decreased in the diclofenac group at 10 and 24 h, and the protein content was significantly lower. The diclofenac group at 24 h had a diminished total number of white blood cells and a reduced content of transforming growth factor-β. Moreover, the diclofenac group had a reduced percentage of neutrophils at 6 h. Significantly increased levels of D-dimers and tissue plasminogen activator were measured at 6 h and of interleukin-10 at 24 h. Neutrophils at the site of pleural abrasion were significantly reduced.

CONCLUSIONS

Systemic application of diclofenac led to a local enhancement of fibrinolysis and attenuation of pro-inflammatory and fibrotic processes necessary for adhesion formation in our model.

Nimesulide inhibits protein kinase C epsilon and substance P in sensory neurons - comparison with paracetamol

In this paper we describe new actions of nimesulide and paracetamol in cultured peripheral neurons isolated from rat dorsal root ganglia (DRG). Both drugs were able to decrease in a dose-dependent fashion the number of cultured DRG neurons showing translocation of protein kinase C epsilon (PKCɛ) caused by exposure to 1 μM bradykinin or 100 nM thrombin. In addition, the level of substance P (SP) released by DRG neurons and the level of preprotachykinin mRNA expression were measured in basal conditions and after 70 minutes or 36 hours of stimulation with nerve growth factor (NGF) or with an inflammatory soup containing bradykinin, thrombin, endothelin-1, and KCl. Nimesulide (10 μM) significantly decreased the mRNA levels of the SP precursor preprotachykinin in basal and in stimulated conditions, and decreased the amount of SP released in the medium during stimulation of neurons with NGF or with the inflammatory soup. The effects of paracetamol (10 μM) on such response was lower. Nimesulide completely inhibited the release of prostaglandin E2 (PGE2) from DRG neurons, either basal or induced by NGF and by inflammatory soup, while paracetamol decreased PGE2 release only partially. Our data demonstrate, for the first time, a direct effect of two drugs largely used as analgesics on DRG neurons. The present results suggest that PKCɛ might be a target for the effect of nimesulide and paracetamol, while inhibition of SP synthesis and release is clearly more relevant for nimesulide than for paracetamol mechanism of action.

Cyclooxygenase-1 or -2--which one mediates lipopolysaccharide-induced hypothermia?

Systemic inflammation is associated with either fever or hypothermia. Fever, a response to mild systemic inflammation, is mediated by cyclooxygenase (COX)-2 and not by COX-1. However, it is still disputed whether COX-2, COX-1, neither, or both mediate(s) responses to severe systemic inflammation, and, in particular, the hypothermic response. We compared the effects of SC-236 (COX-2 inhibitor) and SC-560 (COX-1 inhibitor) on the deep body temperature (T(b)) of rats injected with a lower (10 microg/kg i.v.) or higher (1,000 microg/kg i.v.) dose of LPS at different ambient temperatures (T(a)s). At a neutral T(a) (30 degrees C), the rats responded to LPS with a polyphasic fever (lower dose) or a brief hypothermia followed by fever (higher dose). SC-236 (2.5 mg/kg i.v.) blocked the fever induced by either LPS dose, whereas SC-560 (5 mg/kg i.v.) altered neither the febrile response to the lower LPS dose nor the fever component of the response to the higher dose. However, SC-560 blocked the initial hypothermia caused by the higher LPS dose. At a subneutral T(a) (22 degrees C), the rats responded to LPS with early (70-90 min, nadir) dose-dependent hypothermia. The hypothermic response to either dose was enhanced by SC-236 but blocked by SC-560. The hypothermic response to the higher LPS dose was associated with a fall in arterial blood pressure. This hypotensive response was attenuated by either SC-236 or SC-560. At the onset of LPS-induced hypothermia and hypotension, the functional activity of the COX-1 pathway (COX-1-mediated PGE(2) synthesis ex vivo) increased in the spleen but not liver, lung, kidney, or brain. The expression of splenic COX-1 was unaffected by LPS. We conclude that COX-1, but not COX-2, mediates LPS hypothermia, and that both COX isoforms are required for LPS hypotension.

Effect of Flunixin Meglumine on Cytokine Levels in Experimental Endotoxemia in Mice

In this study, effect of flunixin meglumine on serum tumour necrosis factor alpha, (TNFalpha) interleukin-1 beta and interleukin-10 levels was investigated in lipopolysaccharide-induced endotoxic mice. Healthy 273 Balb/C mice were used and divided into three equal groups. Group 1 was injected lipopolysaccharide (Escherichia coli 0111:B4, 250 microg/mouse, intraperitoneally), Group 2 was injected flunixin meglumine (2.5 mg/kg, subcutaneously), and Group 3 was injected lipopolysaccharide + flunixin meglumine. After the treatments, at 0., 1., 2., 3., 6., 12., 24th hours and 3., 5., 7., 14., 21., 28th days blood samples were taken from seven mice in each group. Serum TNFalpha, interleukin-1 beta and interleukin-10 levels were measured using commercially available kits by enzyme-linked immunoassay. Flunixin meglumine did not affect the cytokine levels in healthy animals. While lipopolysaccharide increased serum TNFalpha, interleukin-1 beta and interleukin-10 levels, flunixin meglumine inhibited increases at levels of all cytokines. As result, flunixin meglumine showed depressor effect on cytokine levels in endotoxemia and the effect may be a reason for the first chosen member of nonsteroid anti-inflammatory drug in endotoxemia.

Neonatal immune challenge exacerbates experimental colitis in adult rats: potential role for TNF-alpha

Early life events and childhood infections have been associated with the development and onset of inflammatory bowel disease in adulthood. However, the consequences of neonatal infection in the development and severity of colitis are not established. We investigated the effects of a neonatal (postnatal day 14) or juvenile (postnatal day 28) immune challenge with LPS on 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced damage and weight loss, as well as on food intake and body temperature in adult rats. Neonatally (n)LPS-treated rats developed more severe colitis than control animals, reflected in a greater loss of weight and a significantly increased macroscopic tissue damage score. These findings were associated with a hypothermic response after TNBS treatment in nLPS rats, but not in neonatally saline-treated rats receiving TNBS. These differences were not seen after TNBS in rats that had received LPS on postnatal day 28. Plasma corticosterone was measured as an index of adult hypothalamic-pituitary-adrenal (HPA) axis activation as was TNF-alpha, a proinflammatory cytokine associated with inflammatory bowel disease. Four days after TNBS treatment, plasma corticosterone was unaltered in all groups; however, TNF-alpha was significantly increased in adult TNBS-treated rats that had LPS as neonates compared with all other groups. In conclusion, neonatal, but not later, exposure to LPS produces long-term exacerbations in the development of colitis in adults. This change is independent of HPA axis activation 4 days after TNBS treatment but is associated with increased circulating TNF-alpha, suggestive of an exaggerated immune response in adults exposed to neonatal infection.

Lipopolysaccharide-induced paw edema model for detection of cytokine modulating anti-inflammatory agents

Cytokines are critical to pathogenesis of inflammatory disorders. So inhibition of their action provides therapeutic benefits in various diseases. Although inhibition of inflammation caused by intraperitoneally administered LPS can identify cytokine modulators, this inflammatory test-agent does not allow one to determine overall anti-inflammatory potential. Functional characteristics of Carrageenan (Cara)-induced edema were valuable for identification of nonsteroidal anti-inflammatory drugs (NSAIDS). Hence, the potential of LPS-induced paw inflammation was investigated and compared to that by Cara. Stimulation of isolated rat peritoneal exudates cells (PEC) with 10 ng/ml LPS, but not Cara, induced IL-6 (3.04+/-0.2 ng/ml) and TNFalpha (1.030.09 ng/ml). At least 100 mg/ml Cara was necessary for detection of IL-6 (2.03+/-0.1 ng/ml) and TNFalpha (0.6+0.09 ng/ml) in PEC. Similar to Cara, subplantar administration of LPS-induced inflammatory paw edema in rats. LPS, but not Cara, induced TNFalpha (2.14+/-0.6 ng/ml) and IL-6 (2.9+/-0.5 ng/ml) in serum at 1 and 3 h, respectively, which returned to basal levels by 5 h. LPS-induced serum TNFalpha (sTNFalpha) levels closely paralleled paw swelling and its neutralization by anti-TNFalpha antibody or inhibition by pentoxifylline and nimesulide correlated with inhibition of inflammation. Similar to earlier reports, rofecoxib induced sTNFalpha at 30 mg/kg and exhibited pro-inflammatory effect by enhancing paw swelling. LPS-induced edema provides a useful functional model for identification of cytokine modulating anti-inflammatory agents.