Novel features of the rat model of inflammatory bowel disease based on 2,4,6-trinitrobenzenesulfonic acidinduced acute colitis

The 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced acute inflammatory bowel disease (IBD) model in the rat is discussed, focusing on the details of the TNBS instillation and highlighting the advantages and limitations of this model. For determination of the time-dependent action of 50% ethanol and different doses of TNBS, male Wistar rats were treated with 50% ethanol or 10 mg or 30 mg of TNBS dissolved in 50% ethanol. The TNBS-induced inflammation peaked 48-72 h after installation and the colitis caused by 30 mg of TNBS was more severe than that caused by 10 mg of TNBS. To test the effectiveness of sulfasalazine (SASP), male rats were treated with 10 mg of TNBS or with 10 mg of TNBS and SASP, and 72 h later the extent of mucosal damage was determined. Orally administered 50 mg/kg/day SASP proved to reduce the TNBS-induced colonic inflammation in rats significantly. The TNBS-induced colitis model facilitates a better understanding of the immunopathological mechanisms of IBD. Optimization of the dose of TNBS and oral SASP as positive control in TNBS-induced colitis in rats furnishes an appropriate test system for new anti-IBD drugs

Oxidative-Stress-Related Alterations in Metabolic Panel, Red Blood Cell Indices, and Erythrocyte Morphology in a Type 1 Diabetic Rat Model

Diabetes mellitus is often associated with vascular complications in which hyperglycemia-induced oxidative stress may be the cause of the impaired vessels and circulating blood cells. The aim of this study was to follow the hyperglycemia-related metabolic and morphological changes in blood and urine samples of Wistar rats. Animals were divided into streptozotocin-induced diabetic (acute and chronic), insulin-treated diabetic, reversed diabetic, and control groups. In chronic diabetic rats, decreases in albumin, total protein, and antioxidant glutation concentration were measured, while glutamic-pyruvic transaminase, alkaline phosphatase, red blood cell (RBC) count, hematocrit, and hemoglobin levels were increased. Moreover, an increased level of the phenotypic variants was detected in the RBC population of the diabetic animals. In conclusion, we verified the sensitivity of RBCs to long-lasting hyperglycemia, and to insulin deficiency, which were both accompanied with an increased level of RBC-derived parameters and the presence of eccentrocytes, hemolyzed RBCs, and codocytes. Moreover, our results show that the response of the RBC glutation system to oxidative stress depends on the duration of hyperglycemia, and that the short-term activation of this defense system is exhausted in a long-lasting oxidative environment. Insulin therapy was effective in the case of most parameters, which clearly emphasizes the importance of maintaining blood glucose at physiological level

Sexual dimorphism of cardiovascular ischemia susceptibility is mediated by heme oxygenase

We investigated the gender differences in heme-oxygenase (HO) enzyme, which produces endogenous vascular protective carbon monoxide (CO). We studied (1) the activity and expression of HO enzymes in the left ventricle (LV) and aorta, (2) basal increase in basal blood pressure provoked by arginine vasopressine (AVP) in vivo, (3) the heart perfusion induced by AVP, (4) the ST segment depression provoked by adrenaline and 30 seconds later phentolamine, and (5) the aorta ring contraction induced by AVP in female and male Wistar rats. We found that HO activity and the expression of HO-1 and HO-2 were increased in female rat aorta and LV. We demonstrated that the basal blood pressure and administration of AVP provoked blood pressure response are increased in the males; the female myocardium was less sensitive towards angina. Both differences could be aggravated by the inhibition of HO. The aorta rings were more susceptible towards vasoconstriction by AVP in males; isolated heart perfusion decrease was higher in males. The HO inhibition aggravated the heart perfusion in both sexes. In conclusion, the increased HO activity and expression in females might play a role in the sexual dimorphism of cardiovascular ischemia susceptibility during the reproductive age. © 2013 Anikó Pósa et al

Investigating KYNA production and kynurenergic manipulation on acute mouse brain slice preparations

Manipulation of kynurenic acid (KYNA) level through kynurenine aminotransferase-2 (KAT-2) inhibition with the aim of therapy in neuro-psychiatric diseses has been the subject of extensive recent research. Although mouse models are of particular importance, neither the basic mechanism of KYNA production and release nor the relevance of KAT-2 in the mouse brain has yet been clarified. Using acute mouse brain slice preparations, we investigated the basal and L-kynurenine (L-KYN) induced KYNA production and distribution between the extracellular and intracellular compartments. Furthermore, we evaluated the effect of specific KAT-2 inhibition with the irreversible inhibitor PF-04859989. To ascertain that the observed KYNA release is not a simple consequence of general cell degradation, we examined the structural and functional integrity of the brain tissue with biochemical, histological and electrophysiological tools. We did not find relevant change in the viability of the brain tissue after several hours incubation time. HPLC measurements proved that mouse brain slices intensively produce and liberate KYNA to the extracellular compartment, while only a small proportion retained in the tissue both in the basal and L-KYN supplemented state. Finally, specific KAT-2 inhibition significantly reduced the extracellular KYNA content. Taken together, these results provide important data about KYNA production and release, and in vitro evidence for the first time of the function of KAT-2 in the adult mouse brain. Our study extends investigations of KAT-2 manipulation to mice in a bid to fully understand the function; the final, future aim is to assign therapeutical kynurenergic manipulation strategies to humans

Anti-Inflammatory Effect of Recreational Exercise in TNBS-Induced Colitis in Rats: Role of NOS/HO/MPO System

There are opposite views in the available literature: Whether physical exercise has a protective effect or not on the onset of inflammatory bowel disease (IBD). Therefore, we investigated the effects of recreational physical exercise before the induction of colitis. After 6 weeks of voluntary physical activity (running wheel), male Wistar rats were treated with TNBS (10 mg). 72 hrs after trinitrobenzene sulphonic acid (TNBS) challenge we measured colonic gene (TNF-, IL-1 , CXCL1 and IL-10) and protein (TNF-) expressions of various inflammatory mediators and enzyme activities of heme oxygenase (HO), nitric oxide synthase (NOS), and myeloperoxidase (MPO) enzymes. Wheel running significantly increased the activities of HO, constitutive NOS (cNOS) isoform. Furthermore, 6 weeks of running significantly decreased TNBS-induced inflammatory markers, including extent of lesions, severity of mucosal damage, and gene expression of IL-1 , CXCL1, and MPO activity, while IL-10 gene expression and cNOS activity were increased. iNOS activity decreased and the activity of HO enzyme increased, but not significantly, compared to the sedentary TNBS-treated group. In conclusion, recreational physical exercise can play an anti-inflammatory role by downregulating the gene expression of proinflammatory mediators, inducing anti-inflammatory mediators, and modulating the activities of HO and NOS enzymes in a rat model of colitis

Oxidative-Stress-Related Alterations in Metabolic Panel, Red Blood Cell Indices, and Erythrocyte Morphology in a Type 1 Diabetic Rat Model

Diabetes mellitus is often associated with vascular complications in which hyperglycemia-induced oxidative stress may be the cause of the impaired vessels and circulating blood cells. The aim of this study was to follow the hyperglycemia-related metabolic and morphological changes in blood and urine samples of Wistar rats. Animals were divided into streptozotocin-induced diabetic (acute and chronic), insulin-treated diabetic, reversed diabetic, and control groups. In chronic diabetic rats, decreases in albumin, total protein, and antioxidant glutation concentration were measured, while glutamic-pyruvic transaminase, alkaline phosphatase, red blood cell (RBC) count, hematocrit, and hemoglobin levels were increased. Moreover, an increased level of the phenotypic variants was detected in the RBC population of the diabetic animals. In conclusion, we verified the sensitivity of RBCs to long-lasting hyperglycemia, and to insulin deficiency, which were both accompanied with an increased level of RBC-derived parameters and the presence of eccentrocytes, hemolyzed RBCs, and codocytes. Moreover, our results show that the response of the RBC glutation system to oxidative stress depends on the duration of hyperglycemia, and that the short-term activation of this defense system is exhausted in a long-lasting oxidative environment. Insulin therapy was effective in the case of most parameters, which clearly emphasizes the importance of maintaining blood glucose at physiological level

Novel features of the rat model of inflammatory bowel disease based on 2,4,6-trinitrobenzenesulfonic acid - induced acute colitis

The 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced acute inflammatory bowel disease (IBD) model in the rat is discussed, focusing on the details of the TNBS instillation and highlighting the advantages and limitations of this model. For determination of the time-dependent action of 50% ethanol and different doses of TNBS, male Wistar rats were treated with 50% ethanol or 10 mg or 30 mg of TNBS dissolved in 50% ethanol. The TNBS-induced inflammation peaked 48-72 h after installation and the colitis caused by 30 mg of TNBS was more severe than that caused by 10 mg of TNBS. To test the effectiveness of sulfasalazine (SASP), male rats were treated with 10 mg of TNBS or with 10 mg of TNBS and SASP, and 72 h later the extent of mucosal damage was determined. Orally administered 50 mg/kg/day SASP proved to reduce the TNBS-induced colonic inflammation in rats significantly. The TNBS-induced colitis model facilitates a better understanding of the immunopathological mechanisms of IBD. Optimization of the dose of TNBS and oral SASP as positive control in TNBS-induced colitis in rats furnishes an appropriate test system for new anti-IBD drugs