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

Colic incidence, risk factors, and therapeutic management in a working horse population in Tuban, Indonesia

Background and Aim

Colic is the primary problem affecting equestrian care worldwide. The primary cause of colic is digestive diseases; however, they can also affect organs from different systems in the abdominal region. In addition to a prior history of the disease and its treatment, risk factors may be assessed to determine the etiology of the disease in horses without or with a history of colic. This study aimed to present a summary of the incidence, risk factors, and medical procedures for colic in horses.

Materials and Methods

Based on owner reports, 223 horses in Tuban, Indonesia, suspected of having colic were investigated. During the investigation of clinical parameters, investigators went door-to-door with interested horse owners to gather information about potential risk factors related to equine colic. Information on horses diagnosed with colic was obtained from the medical records of treatment. A Chi-square test was used to investigate the potential association between the risk factors, medical protocol, and the outcome of colic in horses.

Results

Of the 187 cases, spasmodic colic was the most common (48.13%), but 17 (9.09%) had no definitive diagnosis. Poor body condition scores (χ2 = 58.73; p < 0.001), wheat bran feeding (χ2 = 26.79; p < 0.001), concentrate (χ2 = 10.66; p < 0.01), less access to water (χ2 = 128.24; p < 0.001), recurrence of colic (χ2 = 85.64; p < 0.001), no deworming program (χ2 = 54.76; p < 0.001), the presence of gastrointestinal parasites (χ2 = 56.79; p < 0.001), stressed physical activity (χ2 = 28.53; p < 0.001), and summer season (χ2 = 7.83; p < 0.01) were the risk factors for colic. We further reported that 185 (98.93%) patients who received the following medical interventions recovered: injection of non-steroidal anti-inflammatory drugs was necessary, Vitamin B complex (χ2 = 39.98; p < 0.001), fluid therapy (χ2 = 92.99; p < 0.001), and gastric intubation (χ2 = 4.09; p < 0.05).

Conclusion

The importance of colic was demonstrated in 187 (83.86%) of the 223 horses investigated in Tuban, Indonesia, documented. In this study, recommendations for medical procedures when colic risk factors have been determined are presented.

Therapeutic regimens of endotoxaemia in sheep

Endotoxaemia is an inflammatory condition which happens due to the presence of outer cell wall layer of Gram-negative bacteria in blood circulation, containing lipopolysaccharide commonly known as endotoxin. This condition causes high mortality in affected animals and sheep are highly susceptible in this regard. Several researchers have emphasised the therapeutic regimens of endotoxaemia and its sequels in sheep. Furthermore, sheep are among the most commonly used animal species in experimental studies on endotoxaemia, and for the past five decades, ovine models have been employed to evaluate different aspects of endotoxaemia. Currently, there are several studies on experimentally induced endotoxaemia in sheep, and information regarding novel therapeutic protocols in this species contributes to better understanding and treating the condition. This review aims to specifically introduce various treatment methods of endotoxaemia in sheep.

Low molecular weight heparin reduces acute phase response and multiple organ dysfunction following Ovine experimental endotoxemia model

Endotoxemia is one of the most common inflammatory situations leading to death of ruminants. Owing to the importance of this condition, several therapeutic regimens have been proposed, evaluated and implemented to treat endotoxemia. It has recently been suggested that low molecular weight heparin may be effective in treating endotoxemia. Thus, the present experimental study was conducted to evaluate the acute phase response and multiple organ dysfunction following the treatment of the Ovine experimental endotoxemia model employing this compound. In this regard, 20 clinically healthy 1-year old Iranian fat-tailed ewes were randomly divided into 4 equal groups, comprising LMWH 50, LMWH 100, Ctrl+, and Ctrl-. Lipopolysaccharide from Escherichia coli serotype O55:B5 at 0.4 μg/kg was intravenously administered to the ewes. Low molecular weight heparin (at 50 and 100 IU/kg) was administrated to LMWH 50 and LMWH 100 groups, respectively. Positive control (Ctrl+) received lipopolysaccharide and treated only by intravenous fluid without any drugs, and negative control (Ctrl-) only received intravenous fluids without lipopolysaccharide or any drugs. All the ewes were clinically evaluated before and 1.5, 3, 4.5, 6 and 24 h after lipopolysaccharide injection, and blood samplings were also performed at those hours. Serum concentrations of serum amyloid A, tumor necrosis factor-alpha, superoxide dismutase, glutathione peroxidase, creatine kinase-MB, homocysteine, total bilirubin, aspartate aminotransferase, and creatinine were measured. Serum concentrations of acute phase proteins, inflammatory cytokines, oxidative stress, cardiovascular, hepatic and renal biomarkers, and clinical parameters were significantly increased following the induction of endotoxemia in the groups receiving lipopolysaccharide. Significantly lower concentration of these markers was observed at 4.5 and 6 h after lipopolysaccharide administration in the sheep treated with LMWH compared to the Ctrl + group. In conclusion, low molecular weight heparin could act as an anti-inflammatory drug by decreasing cytokines and acute phase proteins, modulating oxidative stress biomarkers, and by reducing multiple organ dysfunction following the induction of endotoxemia by Escherichia coli serotype O55:B5 in Iranian fat-tailed sheep in a dose-dependent manner. Furthermore, the anti-inflammatory effects of low molecular weight heparin at 100 IU/kg were significantly higher than 50 IU/kg in the treatment of endotoxemic sheep.

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.

Disruption of female reproductive function by endotoxins

Endotoxemia can be caused by obesity, environmental chemical exposure, abiotic stressors and bacterial infection. Circumstances that deleteriously impact intestinal barrier integrity can induce endotoxemia, and controlled experiments have identified negative impacts of lipopolysaccharide (LPS; an endotoxin mimetic) on folliculogenesis, puberty onset, estrus behavior, ovulation, meiotic competence, luteal function and ovarian steroidogenesis. In addition, neonatal LPS exposures have transgenerational female reproductive impacts, raising concern about early life contacts to this endogenous reproductive toxicant. Aims of this review are to identify physiological stressors causing endotoxemia, to highlight potential mechanism(s) by which LPS compromises female reproduction and identify knowledge gaps regarding how acute and/or metabolic endotoxemia influence(s) female reproduction.

Estimating glucose requirements of an activated immune system in growing pigs

Activated immune cells become obligate glucose utilizers, and a large i.v. lipopolysaccharide (LPS) dose causes insulin resistance and severe hypoglycemia. Therefore, study objectives were to quantify the amount of glucose needed to maintain euglycemia following an endotoxin challenge as a proxy of leukocyte glucose requirements. Fifteen fasted crossbred gilts (30.3 ± 1.7 kg) were bilaterally jugular catheterized and assigned 1 of 2 i.v. bolus treatments: control (CON; 10 mL sterile saline; = 7) or LPS challenge + euglycemic clamp (LPS-Eu; 055:B5; 5 μg/kg BW; 50% dextrose infusion to maintain euglycemia; = 8). Following administration, blood glucose was determined every 10 min and dextrose infusion rates were adjusted in LPS-Eu pigs to maintain euglycemia for 8 h. Pigs were fasted for 8 h prior to the bolus and remained fasted throughout the challenge. Rectal temperature was increased in LPS-Eu pigs relative to CON pigs (39.8 vs. 38.8°C; < 0.01). Relative to the baseline, CON pigs had 20% decreased blood glucose from 300 to 480 min postbolus ( = 0.01) whereas circulating glucose content in LPS-Eu pigs did not differ ( = 0.96) from prebolus levels. A total of 116 ± 8 g of infused glucose was required to maintain euglycemia in LPS-Eu pigs. Relative to CON pigs, overall plasma insulin, blood urea nitrogen, β-hydroxybutrate, lactate, and LPS-binding protein were increased in LPS-Eu pigs (295, 108, 29, 133, and 13%, respectively; ≤ 0.04) whereas NEFA was decreased (66%; < 0.01). Neutrophils in LPS-Eu pigs were decreased 84% at 120 min postbolus and returned to CON levels by 480 min ( < 0.01). Overall, lymphocytes, monocytes, eosinophils, and basophils were decreased in LPS-Eu pigs relative to CON pigs (75, 87, 70, and 50%, respectively; ≤ 0.05). These alterations in metabolism and the large amount of glucose needed to maintain euglycemia indicate nutrient repartitioning away from growth toward the immune system. Glucose is an important fuel for the immune system, and data from this study established that the glucose requirements of an intensely and acutely activated immune system in growing pigs are approximately 1.1 g/kg BW/h.