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1.
Topical application of prostaglandin E2 (PGE2) gel to the surface of the uterine tubes via a laparoscopic procedure improved embryo recovery rates or pregnancy rates in 28 subfertile mares suspected of uterine tubal pathology. Gelatinous masses may occlude the lumen of the uterine tube and prevent sperm from reaching the site of fertilization or prevent embryos from reaching the uterus. PGE2 is secreted by the early equine embryo, promoting passage of the embryo into the uterus; topical administration of PGE2 onto the surface of the uterine tube has been shown to stimulate early transport of the embryo into the uterus. Embryos were produced or a pregnancy was obtained from 24 of the 28 barren mares treated with direct laparoscopic application of 0.2 mg of PGE2 to their uterine tubes. Mares had been barren for an average duration of 1.9 ± 0.6 years and an average of 6.9 ± 3.8 estrous cycles prior to treatment, without donating an embryo or becoming pregnant. Seventeen of 20 mares bred as embryo donors produced one or more embryos with an average of 2.1 ± 1.9 embryos collected per mare (0.45 embryos per cycle) after PGE2 treatment. Seven of 8 mares bred to carry their own pregnancy became pregnant within the first two cycles following PGE2 treatment. These 8 mares were bred an average of 5.6 ± 1.8 cycles without a pregnancy prior to treatment. The laparoscopic PGE2 procedure was performed during various stages of the estrous cycle; the stage varied among treated mares.  相似文献   

2.
Obesity is associated with inflammatory disorders in humans, including degenerative joint disease. While obesity is endemic in horses, its relationship to equine degenerative joint disease has not been explored. The current study sought to describe relationships between: body weight (BW), body condition score (BCS), lameness grade (AAEP), total body fat mass (kg; FM) and fat per cent (FP) [multifrequency bioelectrical impedance analysis (mfBIA)], age, gender, activity level (AL), synovial fluid (SF) and plasma (PL) PGE2 and glycosaminoglycan (GAG) in horses. During this field investigation, the BCS (of nine) of 54 horses at multiple farms in southern Ontario, Canada, was determined. Horses were categorized as thin (BCS=3/9; n = 6), moderate (BCS=4 or 5/9; n = 18), overweight (BCS=6 or 7/9; n = 19) or obese (BCS=8 or 9/9; n = 11). Total fat mass (kg) and body fat% was measured using mfBIA, lameness was assessed (AAEP lameness scale) and synovial fluid was collected via aseptic arthrocentesis from the left intercarpal joint for assessment of inflammatory biomarkers (PGE2, GAG). Means were compared with a one‐way ANOVA; correlation coefficients were calculated using a Spearman Rank Order Correlation to reveal correlations between variables. BCS was positively correlated with BW, FM, FP, AL and PL‐PGE2. BW was also significantly positively correlated with PL‐PGE2. It is concluded that BCS is significantly correlated with PL‐PGE2, due in part to the combined effect of AL and body condition. Net inflammatory effects of body fat on risk for joint disease require further study.  相似文献   

3.
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4.
The horse milk gains increasing interest as a food product for sensitive consumers, such as children with food allergies or elderly people. We investigated the plasma and milk disposition, faecal excretion and efficacy of per os ivermectin (IVM) and pour‐on eprinomectin (EPM) in horses. Ten mares were divided into two groups. The equine paste formulation of IVM and bovine pour‐on formulation of EPM were administered orally and topically at dosage of 0.2 and 0.5 mg/kg bodyweight. Blood, milk and faecal samples were analysed using high‐performance liquid chromatography. The plasma concentration and persistence of IVM were significantly greater and longer compared with those of EPM. Surprisingly, EPM displayed a much higher disposition rate into milk (AUCmilk/plasma: 0.48) than IVM (AUCmilk/plasma: 0.19). IVM exhibited significantly higher faecal excretion (AUCfaeces: 7148.54 ng·d/g) but shorter faecal persistence (MRTfaeces: 1.17 days) compared with EPM (AUCfaeces: 42.43 ng·d/g and MRTfaeces: 3.29 days). Faecal strongyle egg counts (EPG) were performed before and at weekly intervals after treatment. IVM reduced the EPG by 96–100% for up to 8 weeks, whereas the reduction in the EPM group varied from 78 to 99%. In conclusion, due to the relatively low excretion in milk, EPM and IVM may be used safely in lactating mares if their milk is used for human consumption. Nevertheless, much lower plasma and faecal availabilities of EPM could result in subtherapeutic concentrations, which may increase the risk of drug resistance in nematodes after pour‐on EPM administration compared with per os IVM.  相似文献   

5.
This study aimed to evaluate and correlate intraocular pressure (IOP), endothelial cell density (CD), and hexagonality (HEX), and the aqueous humor prostaglandin E2 (PGE2) concentration in dogs with mature (MG, n = 8) and hypermature (HG, n = 8) cataracts. Eight laboratory beagles with no ocular abnormalities were included as a control group (CG). The IOP was measured using a digital applanation tonometer. Noncontact specular microscopy was used to evaluate CD and HEX. Samples of aqueous humor were used to determine prostaglandin E2 concentration using enzyme‐linked immunoassay. Data were compared by anova and Bonferroni's multiple comparison test, and possible correlations among the PGE2 aqueous concentration and corneal endothelium cell parameters were assessed by Person′s test (P < 0.05). Average values of IOP (P = 0.45) and CD (P = 0.39) were not significantly different between MG, HM, and CG. Average values of HEX were lower, and PGE2 concentration was increased in the MG and HG in comparison with CG (P < 0.05); however, such parameters did not change significantly between MG and HG (P > 0.05). PGE2 values did not correlate with IOP, CD, and HEX in any group (P > 0.05). Although there were a small number of dogs studied, our results demonstrated that cataract progression from mature to hypermature did not have a significant change in PGE2 aqueous concentration, IOP, corneal endothelial cell count, or morphology. In addition, PGE2 concentration was not correlated with parameters of the corneal endothelium or IOP in dogs with mature or hypermature cataracts.  相似文献   

6.
The aim of this study was to determine the pharmacokinetics and prostaglandin E2 (PGE2) synthesis inhibiting effects of intravenous (IV) and transdermal (TD) flunixin meglumine in eight adult female Boer goats. A dose of 2.2 mg/kg was administered intravenously (IV) and 3.3 mg/kg administered TD using a cross‐over design. Plasma flunixin concentrations were measured by LC‐MS/MS. Prostaglandin E2 concentrations were determined using a commercially available ELISA. Pharmacokinetic (PK) analysis was performed using noncompartmental methods. Plasma PGE2 concentrations decreased after flunixin meglumine for both routes of administration. Mean λz‐HL after IV administration was 6.032 hr (range 4.735–9.244 hr) resulting from a mean Vz of 584.1 ml/kg (range, 357.1–1,092 ml/kg) and plasma clearance of 67.11 ml kg?1 hr?1 (range, 45.57–82.35 ml kg?1 hr?1). The mean Cmax, Tmax, and λz‐HL for flunixin following TD administration was 0.134 μg/ml (range, 0.050–0.188 μg/ml), 11.41 hr (range, 6.00–36.00 hr), and 43.12 hr (15.98–62.49 hr), respectively. The mean bioavailability for TD flunixin was calculated as 24.76%. The mean 80% inhibitory concentration (IC80) of PGE2 by flunixin meglumine was 0.28 μg/ml (range, 0.08–0.69 μg/ml) and was only achieved with IV formulation of flunixin in this study. The PK results support clinical studies to examine the efficacy of TD flunixin in goats. Determining the systemic effects of flunixin‐mediated PGE2 suppression in goats is also warranted.  相似文献   

7.
Interferon‐τ (IFN‐τ) has been recognized as the primary embryonic signal responsible for maternal recognition of pregnancy. Uterine endometrium produces both prostaglandin F2α (PGF2α) and prostaglandin E2 (PGE2). PGF2α is responsible for the luteolysis; however, PGE2 favours establishment of pregnancy by its luteoprotective action. In this study, the dose‐response effect of recombinant bovine IFN‐τ (rbIFN‐τ) on prostaglandin (PG) production by buffalo endometrial stromal cells cultured in vitro was studied. Buffalo endometrial stromal cells were isolated by double enzymatic digestion, initially with trypsin III followed by a cocktail of trypsin III, collagenase type II and DNase I and subsequently cultured till confluence. Further, cells were treated with different doses of rbIFN‐τ (0.001, 0.01, 0.1, 1.0 and 10 μg/ml) and keeping a separate set of control. Culture supernatant was collected after 6, 12 and 24 h of treatment. PG levels in the culture supernatant were measured by enzyme immune assay (EIA) and total cellular protein estimated by Bradford method. Results indicated that buffalo endometrial stromal cells following rbIFN‐τ treatment enhanced the secretion of both PGE2 and PGF2α, and also its ratio in a strict dose‐dependent manner with a significant increase (p < 0.01) in PGE2 production at 1 μg/ml dose of rbIFN‐τ and maximal stimulation for both PG was observed at 10 μg/ml. Further, both PG production and its ratio were increased significantly (p < 0.01) in a time‐dependent fashion in all the groups at 6, 12 and 24 h post‐treatment with highest level achieved at 24 h as compared with control. Absolute levels of PGE2 remained higher than PGF2α indicating PGE2 as the major PG produced by endometrial stromal cells. The dose‐dependent response of rbIFN‐τ signifies the importance of optimum concentration of IFN‐τ for the embryonic development especially during the critical period to establish successful pregnancy.  相似文献   

8.
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9.
The aim of this study was to determine the pharmacokinetics and prostaglandin E2 (PGE2) synthesis inhibiting effects of intravenous (IV) and transdermal (TD) flunixin meglumine in eight, adult, female, Huacaya alpacas. A dose of 2.2 mg/kg administered IV and 3.3 mg/kg administered TD using a cross‐over design. Plasma flunixin concentrations were measured by LC‐MS/MS. Prostaglandin E2 concentrations were determined using a commercially available ELISA. Pharmacokinetic (PK) analysis was performed using noncompartmental methods. Plasma PGE2 concentrations decreased after IV flunixin meglumine administration but there was minimal change after TD application. Mean t1/2λz after IV administration was 4.531 hr (range 3.355 to 5.571 hr) resulting from a mean Vz of 570.6 ml/kg (range, 387.3 to 1,142 ml/kg) and plasma clearance of 87.26 ml kg?1 hr?1 (range, 55.45–179.3 ml kg?1 hr?1). The mean Cmax, Tmax and t1/2λz for flunixin following TD administration were 106.4 ng/ml (range, 56.98 to 168.6 ng/ml), 13.57 hr (range, 6.000–34.00 hr) and 24.06 hr (18.63 to 39.5 hr), respectively. The mean bioavailability for TD flunixin was calculated as 25.05%. The mean 80% inhibitory concentration (IC80) of PGE2 by flunixin meglumine was 0.23 µg/ml (range, 0.01 to 1.38 µg/ml). Poor bioavailability and poor suppression of PGE2 identified in this study indicate that TD flunixin meglumine administered at 3.3 mg/kg is not recommended for use in alpacas.  相似文献   

10.
Mast cells constitute part of the cellular immune system of the genital tract. They play a potential role in cervical remodelling during parturition and are subject to the influence of ovarian steroids. In this study, the influence of oestradiol‐17β and progesterone on the distribution of mast cells in equine vaginal, cervical and uterine tissue was evaluated. Genital tracts were retrieved from healthy mares at a local slaughterhouse. The cervix was divided along the longitudinal axis into five equivalent regions from cranial to caudal (R1 to R5). Toluidine blue staining was used for the detection of mast cells. Hormone values were determined via radioimmunoassay. In cervical tissue, mast cells were present at higher frequency and higher density than in vaginal and uterine tissue. Statistically significant differences were obtained between cervical R1 (cranial) and uterus as well as cervical R2 and uterus (p < 0.05). In cervical tissue, an association between the presence of mast cells and peripheral oestrogen concentrations was observed, whereas such correlation could not be established for vaginal and uterine tissue. With increasing oestradiol‐17β concentrations, the density of mast cells in cervical tissue increased to a statistically significant degree in the cranial (r = 0.46; p = 0.05) and caudal (r = 0.5; p = 0.03) regions. We propose that mast cells play a role in the cyclic remodelling of the equine cervix during the course of the oestrous cycle. Elucidation of mechanisms controlling cervical remodelling could contribute to development of therapies for mares showing a lack in cervical opening during oestrus.  相似文献   

11.
Despite the severity and common occurrence of equine endotoxaemia, the available anti‐endotoxic treatments do not effectively target key inflammatory mechanisms such as leucocyte activation and cytokine production. In this study, four compounds with potential anti‐endotoxic effects, namely rolipram, azithromycin, ethyl pyruvate and metformin, were investigated in vitro using equine whole blood stimulated with bacterial lipopolysaccharide. TNF‐α and IL‐1β production were measured in plasma. Rolipram was the most potent inhibitor of cytokine production (IC50 0.84 and 4.68 μm for TNF‐α and IL‐1β, respectively) with almost complete inhibition of TNF‐α, but inhibited IL‐1β by only 39.46%. Azithromycin produced almost complete inhibition of both cytokines, but tended to be less potent than rolipram (IC50 10.66 and 17.4 μm for TNF‐α and IL‐1β, respectively). Metformin inhibited TNF‐α production with similar potency to rolipram and azithromycin (IC50 3.35 μm ) but showed significantly lower efficacy (45.93%; P < 0.05), and had no inhibitory effect on IL‐1β. Ethyl pyruvate was the least potent (IC50 68.35 μm and >10 mm for TNF‐α and IL‐1β production, respectively). Further work is required to investigate whether these or related compounds may have potential use in the treatment of equine endotoxaemia in vivo.  相似文献   

12.
Pregnancy rates after embryo transfer (ET) are disappointing in donkey species. This study aims to report two successful ET of mini-donkey embryos using Brazilian Northeastern jennies as recipients. Eighteen embryo flushes were performed 9 days post-ovulation in two non-pregnant mini-donkeys jennies (11 and 7 cycles per jenny). Eleven embryos (61%, 11/18) were collected and transferred to Brazilian Northeastern jennies 4–6 days post-ovulation by conventional (n = 6) or an alternative (n = 5) technique. The alternative method consisted of inserting a Polansky equine vaginal speculum smeared with lubricant in the vagina of the recipient jenny. The arms of the speculum were extended to allow the visualization of the cervix. Then, using an adapted crafted, elongated, toothed tissue grasping forceps, the external cervical os was held, and the cervix was gently pulled backward, aiming to straight the cervical canal. The ET gun was inserted through the vagina and cervix by visual inspection, and the embryo was released into the uterine lumen. All embryos collected were Grade 1 and classified as Expanded Blastocysts. No jennies become pregnant after conventional ET (0/6), whereas two recipient jennies (40%, 2/5) become pregnant and delivered offspring in the following year after ET using the alternative technique. In conclusion, Brazilian Northeastern jennies can be used as embryo recipients using the alternative method proposed in the present study. However, further investigations are needed to improve the knowledge and results of ET in donkey species.  相似文献   

13.
The tortuous nature of the ovine cervix restricts the transcervical passage of the cannula, and many studies have aimed to understand the endocrine mechanism of the remodelling of cervical tissue in adult ewe. However, little is known about the remodelling of the cervical tissue during the prepubertal development of the lambs. To obtain histochemical and biochemical evidence about the nature of the prepubertal development of the cervix of the ewe, cervices of Corriedale lambs obtained at 0, 1, 2, 4, 6 and 8 months of age (n = 5 to 6 in each) were processed. Neutral and acidic glycosaminoglycans (by PAS‐Alcian stain) were weakly in the cervical stroma and not shown change during the development, whereas the percentage volume of fibrillar collagen (by van Gieson stain) increases throughout the experimental period in the superficial fold stroma and deep wall stroma (p < 0.05). The relative cervical weight (g/kg of body weight) and the collagen concentration (by spectrophotometry, mg/mg wet tissue) showed an early decreasing phase from months 0 to 4 and a later increasing phase from months 4 to 8 (p < 0.05). The latent form of matrix metalloproteinase‐2 (MMP‐2) detected by gelatin zymography (ng/mg protein) decreased from months 0 to 2 and increased from months 4 to 8, whereas the activated form decreased from months 0 to 2, remained low until month 6 and then recovered on month 8 (p < 0.0001). Data suggest that the relative cervical weight biphasic pattern during the development is related to MMP‐2‐dependent changes in the collagen content.  相似文献   

14.
Intervertebral disc disease, as well as the associated alteration of the radiographic intervertebral disc space width, has been reported in horses. Disc height index (DHI) has proven to be an accurate and objective parameter in other species but data related to this parameter are lacking in horses. Therefore, the aims of this retrospective longitudinal diagnostic accuracy study were (a) to evaluate the reliability of measurements within and between observers of the equine Disc Width Index (EDWI) as a parameter for radiographic equine cervical intervertebral disc space width, and (b) to evaluate the sequential development of the EDWI over time. For this, EDWI from all intervertebral disc spaces between second cervical (C) to first thoracic (Th) vertebrae were obtained in a group of 39 Dutch Warmblood horses at 1, 5, and 18 months of age, by one European College of Veterinary Diagnostic Imaging (ECVDI) board‐certified veterinary radiologist (S.V.) and two veterinary students. Bland‐Altmann plots and intraclass Correlation Coefficient revealed a good intra‐ and interobserver agreement. A linear mixed‐effect model did reveal that mean EDWI increases significantly toward the caudal cervical spine, but did not differ significantly for a certain location over time or between sexes. Spearman's rank test did show a significant correlation between the vertebral alignment angle induced by different head‐neck positions and a normalized EDWI (ρ = 0.33, P < .0001). Student's t‐test revealed that the presence of C6‐C7 transposition of the transverse processes did not influence EDWI significantly. It was concluded that EDWI represents a reliable parameter for equine cervical radiographic intervertebral disc space width. Practical implementation of EDWI warrants monitoring in a group of adult horses while maintaining a standardized head‐neck position.  相似文献   

15.
The aim of this study was to evaluate the efficacy of Cervidil®, a prostaglandin E2 (PgE2)-releasing vaginal insert used for induction of cervical ripening and labour in women, to enhance the ease of transcervical artificial insemination (TCAI) in anestrous ewes (June). It was hypothesized that the use of Cervidil® prior to AI would cause dilation of the cervix, and thus alleviate the difficulty associated with traversing the cervix for semen deposition in sheep. Cervidil® was inserted 12 h before insemination in six Rideau-Arcott ewes; six ewes served as untreated controls.Semen was deposited into the uterus of all six treated ewes but TCAI was possible only in four of the six control ewes. It can be concluded that Cervidil® facilitated transcervical semen deposition in anestrous ewes. The treatment with Cervidil® has the promise of a technique to improve transcervical AI and to enable non-invasive embryo transfer procedures in sheep.  相似文献   

16.
Objectives Phase I: To evaluate levels of prostaglandin E2 (PGE2), nitrites and nitrates (NOx), tumor necrosis factor‐alpha (TNF‐α) and expression of inducible cyclo‐oxygenase (COX‐2), nitric oxide synthase (NOS‐2), and matrix metalloproteinases (MMP‐3 and ‐9) in canine aqueous humor following repeated anterior chamber paracenteses (ACP). Phase II: to evaluate the effect of carprofen on PGE2, NOx, and TNF‐α in canine aqueous humor following ACP. Animals studied Four beagles in phase I and 8 beagles in phase II. Procedures Phase I: ACP was performed at time (T) 0, 4 and 8 h. Phase II: A randomized, placebo‐controlled cross‐over design with four dogs per group where carprofen was given 4.4 mg/kg/day on day (D) 1, 2 and 3. ACP was performed at T0 and T1.5 on D3. Statistical analysis was performed with repeated measures anova and post hoc Tukey‐Kramer multiple‐comparison procedure. In phase II, TNF‐α level was analyzed with a Wilcoxon signed‐rank test. Results Phase I: PGE2 significantly increased (P < 0.0001) to plateau at T4. NOX was decreased at T4 (P < 0.06), but increased at T8 (P < 0.0001). COX‐2 showed detectable expression only at T8. TNF‐α, NOS‐2, MMP‐3 and ‐9 were undetectable at all time points. Phase II: At T1.5, PGE2 was significantly elevated in both groups but was lower in the carprofen group (P = 0.037). NOx and TNF‐α did not statistically increase in either group. Conclusions Following ACP, significant increases in PGE2 levels confirmed inflammation characterized by a rise of COX‐2. The NOx pathway took longer to induce as compared with PGE2. Carprofen decreased PGE2 levels and could help control intraocular inflammation.  相似文献   

17.
Briston, L., Dudhia, J., Lees, P. Age‐related differences in prostaglandin E2 synthesis by equine cartilage explants and synoviocytes. J. vet. Pharmacol. Therap. 33 , 268–276. Time‐ and concentration‐related actions of lipopolysaccharide (LPS) on the synthesis of prostaglandin E2 (PGE2) were investigated in cartilage explants and synoviocytes harvested from 3 age groups of horses, all with clinically normal joint function: group A <10 years; group B 11–20 years and group C >20 years. Cartilage explants from group A horses were least and those from group C were most sensitive to LPS. Significant increases in PGE2 concentration (P ≤ 0.01) were obtained in group C horses in response to LPS concentrations of 1.0 μg/mL (and higher) after exposure for 24, 36 and 48 h, whereas explants from group A horses failed to respond to LPS at concentrations up to 100 μg/mL after exposure times up to 48 h. In contrast, synoviocytes from group A horses were most and those from group C horses were least sensitive to LPS stimulation. Synoviocytes from group A horses responded to LPS concentrations of 1 μg/mL (and higher) with significantly increased concentrations of PGE2 at 24 and 36 h. Significant but numerically smaller increases in PGE2 concentration were induced by LPS in synoviocytes from groups B and C. As the effects of high PGE2 concentrations are catabolic for cartilage, these observations suggest that both synoviocytes and chondrocytes might exert roles in the degenerative changes which occur in cartilage in horses with osteoarthritis.  相似文献   

18.
The objective of this project was to determine early tissue biochemical events associated with increased colonic secretion during the acute stage of castor-oil-induced colitis by measuring cecal mucosal and submucosal malondialdehyde (MDA) and prostaglandin E2 (PGE2), levels in ponies. Intestinal tissue (inflamed or healthy) samples were obtained from 4 age- and sex-matched Shetland ponies. Biochemical methods were used to determine MDA and PGE2 levels in intestinal tissue samples from inflamed and healthy equine intestine. Inflamed tissue MDA and PGE2 levels increased with time after castor oil challenge and correlated with granulocyte infiltration, as determined by myeloperoxidase levels in a companion study. Elevated intestinal tissue MDA levels suggest that lipid peroxidation could be attributed to reactive oxygen metabolites (ROM) released from stimulated, recruited, and resident granulocytes. Tissue levels of MDA and PGE2 suggest a role for granulocyte-derived mediators of intestinal inflammation in the massive secretory response in cases of acute equine colitis. Tissue MDA and PGE2 levels may be useful laboratory tools to quantify and characterize intestinal secretory inflammatory responses in acute inflammatory conditions in the equine colon.  相似文献   

19.
Flunixin meglumine (FM) is a commonly used Nonsteroidal anti‐inflammatory drug (NSAID) in horses, but clinical efficacy is often unsatisfactory. Ketorolac tromethamine (KT) demonstrates superior efficacy compared to other NSAIDs in humans, but its anti‐inflammatory effects have not been investigated in the horse. Safety of repeated dosing of KT has not been evaluated. The first objective was to conduct a dose determination study to verify that a previously described dosage of KT would inhibit Lipopolysaccharide (LPS)‐induced eicosanoid production in vitro, and to compare KT effects of this inhibition to those of FM. Then, a randomized crossover study was performed using nine healthy horses to evaluate plasma concentrations of KT and FM following IV administration. Administered dosages of KT and FM were 0.5 mg/kg and 1.1 mg/kg, respectively. Safety following six repeated doses of KT was assessed. Ketorolac tromethamine and FM suppressed LPS‐induced Thromboxane B2 (TXB2) and Prostaglandin E2 (PGE2) production in vitro for up to 12 hr. Intravenous administration produced plasma concentrations of KT and FM similar to previous reports. No adverse effects were observed. A KT dosage of 0.5 mg/kg IV inhibited LPS‐induced eicosanoids in vitro, and repeated dosing for up to 3 days appears safe in healthy horses. Investigation of in vivo anti‐inflammatory and analgesic effects of KT is warranted.  相似文献   

20.
Polymyxin‐B is used to treat equine systemic inflammation. Bacterial toxins other than lipopolysaccharide (LPS) contribute to systemic inflammation but the effects of polymyxin‐B on these are poorly defined. Whole blood aliquots from six healthy horses diluted 1:1 with RPMI were incubated for 21 hr with 1 μg/ml of LPS, lipoteichoic acid (LTA) or peptidoglycan (PGN) in the presence of increasing concentrations of polymyxin‐B (10–3000 μg/ml). A murine L929 fibroblast bioassay was used to measure TNF‐α activity. Polymyxin‐B significantly inhibited the effects of all three bacterial toxins. Analysis of variance showed the IC50 value for polymyxin‐B for TNF‐α inhibition caused by LTA (11.19 ± 2.89 μg/ml polymyxin‐B) was significantly lower (p = .009) than the values for LPS (46.48 ± 9.93 μg/ml) and PGN (54.44 ± 8.97 μg/ml). There was no significant difference in IC50 values between LPS and PGN (p > .05). Maximum inhibition of TNF‐α was 77.4%, 73.0% and 82.7% for LPS, PGN and LTA, respectively and was not significantly different between toxins. At the two highest concentrations of polymyxin‐B, TNF‐α began to increase. These data suggest that polymyxin‐B may inhibit the effects of bacterial toxins other than LPS and might be a more potent inhibitor of LTA than LPS or PGN.  相似文献   

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