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

Pharmacokinetics and efficacy of orally administered acetaminophen (paracetamol) in adult horses with experimentally induced endotoxemia

BACKGROUND

Acetaminophen has been evaluated in horses for treatment of musculoskeletal pain but not as an antipyretic.

OBJECTIVES

To determine the pharmacokinetics and efficacy of acetaminophen compared to placebo and flunixin meglumine in adult horses with experimentally induced endotoxemia.

ANIMALS

Eight university owned research horses with experimentally induced endotoxemia.

METHODS

Randomized placebo controlled crossover study. Horses were treated with acetaminophen (30 mg/kg PO; APAP), flunixin meglumine (1.1 mg/kg, PO; FLU), and placebo (PO; PLAC) 2 hours after administration of LPS. Plasma APAP was analyzed via LC-MS/MS. Serial CBC, lactate, serum amyloid A, heart rate and rectal temperature were evaluated. Serum IL-1β, IL-6, IL-8, IL-10, and TNF-α were evaluated by an equine-specific multiplex assay.

RESULTS

Mean maximum plasma APAP concentration was 13.97 ± 2.74 μg/mL within 0.6 ± 0.3 hour after administration. At 4 and 6 hours after treatment, both APAP (P = <.001, P = .03, respectively) and FLU (P = .0045 and P < .001, respectively) had a significantly greater decrease in rectal temperature compared to placebo. FLU caused greater heart rate reduction than APAP at 4 and 6 hours (P = .004 and P = .04), and PLAC at 4 hours (P = .05) after treatment.

CONCLUSIONS AND CLINICAL IMPORTANCE

The pharmacokinetics of acetaminophen in endotoxemic horses differ from those reported by previous studies in healthy horses. Acetaminophen is an option for antipyresis in clinical cases, particularly when administration of traditional NSAIDs is contraindicated.

Effects of different cyclooxygenase inhibitors on prostaglandin E₂ production, steroidogenesis and ovulation of bovine preovulatory follicles

Ovulation is an inflammation-like process, and cyclooxygenase-2 (COX-2)-dependent production of prostaglandin E₂ (PGE₂) is its key mediator. Balanced regulation of inflammatory processes in high-yielding dairy cows may be essential for physiological ovulation and fertility. This study aimed to elucidate the mechanisms underlying ovulation failure and cyst development after disturbing intrafollicular inflammatory cascades. Therefore, nonselective (indomethacin and flunixin-meglumine), COX-2 selective (meloxicam), and highly COX-2 selective (NS-398) inhibitors were injected into preovulatory follicles 16 h after administration of GnRH, and ovulation was monitored via ultrasound examination. Additionally, follicular fluid was collected after injection of indomethacin, meloxicam, and NS-398. Moreover, primary granulosa cell cultures from preovulatory follicles were prepared and treated with indomethacin, meloxicam, and NS-398. The concentrations of 17β-estradiol, progesterone, and prostaglandin E₂ (PGE₂) in the follicular fluid and cell supernatant were estimated. Indomethacin and flunixin-meglumine blocked ovulation, even at low doses, and led to ovarian cyst development. The selective and highly selective COX-2 inhibitors meloxicam and NS-398 were not effective in blocking ovulation. However, indomethacin, meloxicam, and NS-398 significantly and comparably reduced PGE₂ concentration in vivo and in vitro (P < 0.05) but had no effect on estradiol or progesterone production. This may contradict the generally accepted hypothesis that PGE₂ is a key mediator of ovulation and progesterone production. Our results suggest a connection between ovarian disorders and inflammatory actions in early postpartum cows.

Inhibition of lipopolysaccharide-induced suppression of luteal function in isolated perfused bovine ovaries

Recently, we observed that lipopolysaccharide (LPS) suppresses corpus luteum (CL) function in isolated perfused ovaries. It remained unclear if this suppression was due to increased luteal PGF_2α secretion or LPS-induced apoptosis. Therefore, possible impacts of PGF_2α and LPS were inhibited by a non-steroidal anti-inflammatory drug (flunixin) and an endotoxin-binding agent (polymyxin B), respectively. Bovine ovaries with a mid-cycle CL were collected immediately after slaughter and perfused for 240 min. After 50 min of equilibration, either flunixin or polymyxin B (5 μg/ml of each) were added to the perfusion medium of six ovaries, respectively. All ovaries (n = 12) were treated with E.coli LPS (0.5 μg/ml) 60 min after the onset of perfusion, and received 500 I.U. of hCG after 210 min of perfusion. Progesterone and PGF_2α were measured in the effluent perfusate every 10 and 30 min, respectively. Biopsies of the CL were collected every 60 min to determine the mRNA expression of the cytokine TNFA and factors of apoptosis (CASP3, -8). Flunixin-treatment inhibited the increase of PGF_2α after LPS-challenge that was observed in the polymyxin B-treated (PX-LPS) ovaries. After hCG-stimulation, progesterone secretion increased (P< 0.05) in group PX-LPS but not in the flunixin-treated (F-LPS) ovaries. Compared to initial values before LPS-challenge, luteal mRNA expression of TNFA and CASP3 was increased (P< 0.05) in group F-LPS at 120 and 180 min, respectively, and those of CASP8 was decreased (P< 0.05) in PX-LPS at 60 and 120 min after LPS-treatment. In conclusion, although flunixin managed to inhibit PGF_2α, it did not suffice to successfully prevent LPS-induced apoptosis. However, endotoxin-binding polymyxin B resulted in luteal responsiveness to hCG after LPS-challenge.

The effects of baicalin on piglets challenged with Glaesserella parasuis

Glaesserella parasuis (G. parasuis) causes porcine vascular inflammation and damage. Baicalin is reported to have antioxidant and anti-inflammatory functions. However, whether baicalin protects piglets against G. parasuis challenge and the potential protective mechanism have not been investigated. Therefore, in this study, we comprehensively examined the protective efficacy of baicalin in piglets challenged with G. parasuis and the possible protective mechanism. Our results show that baicalin attenuated the release of the inflammation-related cytokines interleukin (IL) 1β, IL6, IL8, IL10, and tumour necrosis factor α (TNF-α) and reduced high mobility group box 1 (HMGB1) production and cell apoptosis in piglets infected with G. parasuis. Baicalin also inhibited the activation of the mitogen-activated protein kinase (MAPK) signalling pathway and protected piglets against G. parasuis challenge. Taken together, our data suggest that baicalin could protect piglets from G. parasuis by reducing HMGB1 release, attenuating cell apoptosis, and inhibiting MAPK signalling activation, thereby alleviating the inflammatory response induced by the bacteria. Our results suggest that baicalin has utility as a novel therapeutic drug to control G. parasuis infection.

Acute toxic effect of lipopolysaccharides to blood tissue in rats and responses to vitamin E and sodium selenite

This work has been prepared to find out changes in the biochemicals with DNA damage, micronucleus, and apoptosis to lipopolysaccharides (LPS) alone or vitamin E (VE) and sodium selenite (SS) in rats' blood tissue. Rats were divided into eight groups according to the treatment into control vitamin E (VE) treatment group (200 mg/kg bw), sodium selenite (SS) treatment (0.35 mg/kg bw) group, VE + SS treatment group (200 + 0.35 mg/kg bw), LPS treatment group (10 mg/kg bw), LPS + VE (10 + 200 mg/kg bw), LPS + SS treatment (10 + 0.35 mg/kg bw), and LPS + SS+VE treatment (10 + 0.35 + 200 mg/kg bw) group for 6 hr. LPS increased malondialdehyde (MDA) level and decreased antioxidant enzymes' activities in rat erythrocytes and leukocytes. DNA damage of leukocytes with comet assay and RAPD-PCR was detected in LPS treatment group. The levels of micronucleus and apoptosis percentage were increased significantly at the end of 6 hr. VE and/or SS protected the LPS-induced erythrocytes and leukocytes against damage as they have caused amelioration of rats by altering the results. As a result, the co-administration of VE and/or SS against LPS-induced damage provides protection. VE and/or SS in patients and animal models with sepsis must be taken in the diet because they are protective against the cellular degradation caused by oxidative damage. PRACTICAL APPLICATIONS: LPS obtained from E. coli is used more frequently in experimental sepsis studies. When LPS is administered to experimental animals, interstitial pneumonia, adult respiratory fatal syndrome, acute tubular necrosis, and fatal effects such as coagulopathy and hypoglycemia may be seen in these animals. The co-treatment of VE and SS may be more effective than using them alone against LPS.

Comparative therapeutic effect of steroidal and non-steroidal anti-inflammatory drugs on pro-inflammatory cytokine production in water buffalo calves (Bubalus bubalis) naturally infected with bronchopneumonia: a randomized clinical trial

In the current study, we compared the therapeutic effects of a non-steroidal and a steroidal anti-inflammatory drug on the production of pro-inflammatory cytokines, interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-12p40 (IL-12p40), interferon gamma (IFNγ), and tumor necrosis factor alpha (TNF-α) in the blood of water buffalo (Bubalus bubalis) calves naturally infected by bronchopneumonia. Twenty-seven buffalo calves (7 ± 2-month-old, 163 ± 12 kg) reared in smallholder farms in El-Dakahlia province in Egypt were identified to have bronchopneumonia and randomly allocated into three equal groups. Ten clinically healthy buffalo calves with negative bronchoalveolar lavage results were served as negative control. Diseased calves were treated with tulathromycin alone, a combination of tulathromycin with dexamethasone (steroidal anti-inflammatory drug) or tulathromycin with flunixin meglumine (non-steroidal anti-inflammatory drug). The results revealed significant elevations (P < 0.05) in the production of selected cytokines in all diseased calves in comparison with healthy animals. Six days post-treatment, a significant inhibition (P < 0.05) in the production of all assessed cytokines was observed in the blood of all treated calves. Interestingly, the serum concentrations of IL-1β and IL-12p40 were returned to the normal levels in pneumonic calves treated with the combination therapy of tulathromycin and flunixin meglumine. A strong significant positive correlation (P < 0.05) was detected between clinical sum scoring and IL-12p40 and TNF-α concentrations. The obtained results indicate the selectively potent anti-inflammatory effect of flunixin meglumine on the production of pro-inflammatory cytokines in pneumonic buffalo calves and highlight the efficacy of flunixin meglumine in the treatment of bronchopneumonia in buffalo calves when used in combination with tulathromycin.

Can proinflammatory cytokine gene expression explain multifidus muscle fiber changes after an intervertebral disc lesion?

STUDY DESIGN

Longitudinal case-controlled animal study.

OBJECTIVE

To investigate the effect of an intervertebral disc (IVD) lesion on the proportion of slow, fast, and intermediate muscle fiber types in the multifidus muscle in sheep, and whether muscle fiber changes were paralleled by local gene expression of the proinflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin 1-β.

SUMMARY OF BACKGROUND DATA

Structure and behavior of the multifidus muscle change in acute and chronic back pain, but the mechanisms are surprisingly poorly understood and the link between structure and behavior is tenuous. Although changes in muscle fiber types have the potential to unify the observations, the effect of injury on muscle fiber distribution has not been adequately tested, and understanding of possible mechanisms is limited.

METHODS

The L1-L2, L3-L4, and L5-L6 IVDs of 11 castrated male sheep received anterolateral lesions. Six control sheep underwent no surgical procedures. Multifidus muscle tissue was harvested at L4 for muscle fiber analysis using immunohistochemistry and L2 for cytokine analysis with polymerase chain reaction for local gene expression of TNF-α and interleukin-1β.

RESULTS

The proportion of slow muscle fibers in multifidus was significantly less in the lesioned animals both ipsilateral and contralateral to the IVD lesion. The greatest reduction in slow fibers was in the deep medial muscle region. A greater prevalence of intermediate fibers on the uninjured side implies a delayed fiber-type transformation on that side. TNF-α gene expression in multifidus was greater on both sides in the lesion animals than in the muscle of control animals. Interleukin-1β was increased only on the injured side.

CONCLUSION

These data provide evidence of muscle fiber changes after induction of an IVD lesion and a parallel increase in TNF-α expression. Proinflammatory cytokine changes provide a novel mechanism to explain behavioral and structural changes in multifidus.

LEVEL OF EVIDENCE

N/A.

Effects of tylosin, tilmicosin and tulathromycin on inflammatory mediators in bronchoalveolar lavage fluid of lipopolysaccharide-induced lung injury

The aim of this study was to determine the anti-inflammatory effects of macrolides through kinetic parameters in bronchoalveolar lavage fluid (BALF) of lipopolysaccharide-induced lung injury. Rats were divided into four groups: lipopolysaccharide (LPS), LPS + tylosin, LPS + tilmicosin and LPS + tulathromycin. BALF samples were collected at sampling times. TNF, IL-1β, IL-6, IL-10 and 13,14-dihydro-15-keto-prostaglandin F2α (PGM) and C-reactive protein (CRP) were analysed. Area under the curve (AUC) and maximum plasma concentration (Cmax) values of inflammatory mediators were determined by a pharmacokinetic computer programme. When inflammatory mediator concentrations were compared between the LPS group and other groups for each sampling time, the three macrolides had no pronounced depressor effect on cytokine levels, but they depressed PGM and CRP levels. In addition, tylosin and tilmicosin decreased the AUC0-24 level of TNF, while tilmicosin decreased the AUC0-24 level of IL-10. Tylosin and tulathromycin decreased the AUC0-24 of PGM, and all three macrolides decreased the AUC0-24 of CRP. Especially tylosin and tulathromycin may have more expressed anti-inflammatory effects than tilmicosin, via depressing the production of inflammatory mediators in the lung. The AUC may be used for determining the effects of drugs on inflammation. In this study, the antiinflammatory effects of these antibiotics were evaluated with kinetic parameters as a new and different approach.

Anti-inflammatory effects of insulin regular and flunixin meglumine on endotoxemia experimentally induced by Escherichia coli serotype O55:B5 in an ovine model

BACKGROUND

Endotoxemia is a major cause of mortality in large animals and there are several therapeutic regimens for the treatment of endotoxemia. Recent studies have suggested the anti-inflammatory effects of insulin in endotoxemic human and laboratory animal models but to the best of our knowledge there is no report on the possible therapeutic effect of insulin in large animal endotoxemia.

OBJECTIVE

This experiment was conducted to evaluate the anti-inflammatory effects of insulin regular compared with flunixin meglumine on the treatment of endotoxemia in sheep.

METHODS

Lipopolysaccharide from Escherichia coli was administered intravenously to ewes. Anti-inflammatory effects of flunixin meglumine (at 2.2 mg/kg) and insulin regular (at 1.5 and 3 IU/kg) were evaluated by determination of serum concentrations of acute phase proteins, inflammatory cytokines and oxidative stress biomarkers.

RESULTS

Insulin regular at 3 IU/kg controlled the acute phase response following endotoxemia induction. The anti-inflammatory potency of insulin regular at 3 IU/kg was significantly higher than at 1.5 IU/kg and of flunixin meglumine at 2.2 mg/kg (P < 0.05).

CONCLUSION

Insulin regular induces its anti-inflammatory effects in a dose-dependent manner. Intravenous use of insulin regular can be a potential new therapeutic regimen for endotoxemia in large animal medicine.

Ethyl pyruvate diminishes the inflammatory response to lipopolysaccharide infusion in horses

REASONS FOR PERFORMING THE STUDY

Endotoxaemia contributes to morbidity and mortality in horses with colic due to inflammatory cascade activation. Effective therapeutic interventions are limited for these horses. Ethyl pyruvate (EP), an anti-inflammatory agent that alters the expression of proinflammatory cytokines, improved survival and organ function in sepsis and gastrointestinal injury in rodents and swine. Therapeutic efficacy of EP is unknown in endotoxaemic horses.

OBJECTIVES

Determine the effects of EP on signs of endotoxaemia and expression of proinflammatory cytokines following administration of lipopolysaccharide (LPS) in horses.

METHODS

Horses received 30 ng/kg bwt LPS in saline to induce signs of endotoxaemia. Next, horses received lactated Ringer's solution (LRS), (n = 6), 150 mg/kg bwt EP in LRS, (n = 6), or 1.1 mg/kg bwt flunixin meglumine (FM), (n = 6). Controls received saline followed by LRS (n = 6). Physical examinations, behaviour pain scores and blood for clinical pathological testing and gene expression were obtained at predetermined intervals for 24 h.

RESULTS

Lipopolysaccharide infusion produced clinical and clinicopathological signs of endotoxaemia and increased expression of tumour necrosis factor alpha (TNFα), interleukin 6 (IL-6) and IL-8 (P<0.001) compared with controls. Leucopenia and neutropenia occurred in all horses that received LPS. Horses treated with EP and FM had significantly (P<0.0001) reduced pain scores compared with horses receiving LPS followed by LRS. Flunixin meglumine was significantly more effective at ameliorating fever compared with EP. Both EP and FM significantly diminished TNFα expression. Ethyl pyruvate significantly decreased, but FM significantly increased, IL-6 expression. Neither EP nor FM altered IL-8 expression.

CONCLUSIONS AND POTENTIAL RELEVANCE

Ethyl pyruvate administered following LPS diminished the clinical effects of endotoxaemia and decreased proinflammatory gene expression in horses. Ethyl pyruvate suppressed expression of proinflammatory cytokines better than FM. However, FM was a superior anti-pyretic compared with EP. Ethyl pyruvate may have therapeutic applications in endotoxaemic horses.

Effects of flunixin meglumine and ketoprofen on mediator production in ex vivo and in vitro models of inflammation in healthy dairy cows

In this study, ex vivo assays were carried out in dairy cows to evaluate the anti-inflammatory effects of two nonsteroidal anti-inflammatory drugs: ketoprofen (KETO) and flunixin meglumine (FM). Twelve healthy Holstein dairy cattle were randomly allocated to two groups (n=6): group 1 received FM and group 2 received KETO at recommended therapeutic dosages. The anti-inflammatory effects of both drugs were determined by measuring the production of coagulation-induced thromboxane B2 (TXB2 ), lipopolysaccharides (LPS) (10 μg/mL)-induced prostaglandin E2 (PGE2 ), and calcium ionophore (60 μm)-induced leukotrien B4 (LTB4 ). Cytokine production was assessed by measuring tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and interleukin-8 (CXCL8) concentrations after incubation in the presence of 10 μg/mL LPS. The IC50 of FM and KETO was determined in vitro by determining the concentration of TXB2 and PGE2 in the presence of scalar drug concentrations (10(-9) -10(-3) m). Both FM and KETO inhibited the two COX isoforms in vitro, but showed a preference for COX-1. FM and KETO showed similar anti-inflammatory effects in the cow.

Effects of enrofloxacin, flunixin meglumine and dexamethasone on disseminated intravascular coagulation, cytokine levels and adenosine deaminase activity in endotoxaemia in rats

The aim of this study was to determine the effects of drugs used in the treatment of endotoxaemia on disseminated intravascular coagulation, cytokine levels and adenosine deaminase activities in endotoxaemic rats. Rats were divided into seven groups. Lipopolysaccharide (LPS) was injected into all groups, including the positive control group. The other six groups received the following drugs: enrofloxacin (ENR), flunixin meglumine (FM), low-dose dexamethasone (DEX), high-dose DEX, ENR + FM + low-dose DEX, and ENR + FM + high-dose DEX. After the treatments, serum and plasma samples were collected at 0, 1, 2, 4, 6, 8, 12, 24 and 48 hours (h). A coagulometer was used to determine the levels of coagulation values, while ELISA was used to assay serum cytokines and adenosine deaminase (ADA). Low-dose DEX alone and combined treatments depressed the levels of cytokines and ADA (from 371 to 70 IU/L at 6 h) significantly and inhibited the decrease of coagulation values (antithrombin from 67 to 140% at 6 h, fibrinogen from 54 to 252 mg/dL at 6 h). In summary, FM + high-dose DEX may be the preferred treatment of endotoxaemia because of its highest effectiveness. FM plus high-dose DEX may be a new therapy for endotoxaemic domestic animals.

Effects of tylosin on serum cytokine levels in healthy and lipopolysaccharide-treated mice

The effects of different doses of tylosin on serum cytokine concentrations were investigated in healthy and lipopolysaccharide-treated mice. The mice were divided into seven groups. Lipopolysaccharide (LPS) was injected into the positive control group. The other six groups received three different tylosin doses concurrently without or with LPS: 10 mg/kg, 100 mg/kg, 500 mg/kg, 10 mg/kg + LPS, 100 mg/kg + LPS and 500 mg/kg + LPS. After treatment, serum samples were collected at 0, 1, 2, 3, 6, 12 and 24 hours. Serum tumour necrosis factor alpha (TNFalpha), interleukin 1beta (IL1beta) and IL10 levels were determined by enzyme-linked immunosorbent assay (ELISA). Tylosin doses of 10 and 100 mg/kg induced no cytokine production in the healthy mice. Tylosin at 500 mg/kg had no effect on TNFalpha or IL1beta production, but it induced IL10 production in healthy mice. All doses of tylosin reduced the elevated TNFalpha and IL1beta in LPS-treated mice but increased their IL10 levels. In conclusion, these data suggest that tylosin has an immunomodulatory effect at the dose recommended for use against infection.