Hemorrhagic shock (HS) following trauma is a leading cause of death among persons under the age of 40. During HS the body undergoes systemic warm ischemia followed by reperfusion during medical intervention. Ischemia/reperfusion (I/R) results in a disruption of cellular metabolic processes that ultimately lead to tissue and organ dysfunction or failure. Resistance to I/R injury is a characteristic of hibernating mammals. The present study sought to identify circulating metabolites in the rat as biomarkers for metabolic alterations associated with poor outcome after HS. Arctic ground squirrels (AGS), a hibernating species that resists I/R injury independent of decreased body temperature (warm I/R), was used as a negative control.
Male Sprague-Dawley rats and AGS were subject to HS by withdrawing blood to a mean arterial pressure (MAP) of 35 mmHg and maintaining the low MAP for 20 min before reperfusing with Ringers. The animals' temperature was maintained at 37 ? 0.5 ?C for the duration of the experiment. Plasma samples were taken immediately before hemorrhage and three hours after reperfusion. Hydrophilic and lipid metabolites from plasma were then analyzed via 1H-NMR from unprocessed plasma and lipid extracts, respectively. Rats, susceptible to I/R injury, had a qualitative shift in their hydrophilic metabolic fingerprint including differential activation of glucose and anaerobic metabolism and had alterations in several metabolites during I/R indicative of metabolic adjustments and organ damage. In contrast, I/R injury resistant AGS, regardless of season or body temperature, maintained a stable metabolic homeostasis revealed by a qualitative 1H-NMR metabolic profile with few changes in quantified metabolites during HS-induced global I/R.
An increase in circulating metabolites indicative of anaerobic metabolism and activation of glycolytic pathways is associated with poor prognosis after HS in rats. These same biomarkers are absent in AGS after HS with warm I/R.
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Polyalthia longifolia var. pendula is used as an antipyretic agent in indigenous systems of medicine. Microglia-mediated inflammation plays an important role in the pathway leading to neuronal cell death in a number of neurodegenerative diseases. The aim of this study was to investigate the effects of 6-hydroxycleroda-3,13-dien-15,16-olide (PL3) extracted from Polyalthia longifolia var. pendula on lipopolysaccharide(LPS)-induced inflammation in microglia-like HAPI cells and primary microglia cultures. In microglia-neuron co-cultures, LPS decreased the cell viability of neuroblastoma SH-SY5Y cells. LPS-induced cell death was attenuated by the NOS inhibitor, L-NAME, the COX-2 inhibitor, NS-398 or the NADPH oxidase inhibitor, DPI, respectively. In LPS-treated microglia cells, PL3 decreased the expression of iNOS, COX-2, gp91 (phox), and NF- kappaBp65, the degradation of I kappaB alpha, and the production of NO, PGE (2), iROS, and TNF- alpha. PL3 also enhanced the expression of HO-1, a cytoprotective and anti-inflammatory enzyme. Moreover, PL3 reduced LPS-activated microglia-induced cell death. The present results suggest that PL3 inhibits microglia-mediated inflammation and inflammation-related neuronal cell death. Therefore, PL3 has potential use for the treatment of inflammation-related neurodegenerative diseases.
Patients with defective osteoclastic acidification have increased numbers of osteoclasts, with decreased resorption, but bone formation that remains unchanged. We demonstrate that osteoclast survival is increased when acidification is impaired, and that impairment of acidification results in inhibition of bone resorption without inhibition of bone formation. We investigated the role of acidification in human osteoclastic resorption and life span in vitro using inhibitors of chloride channels (NS5818/NS3696), the proton pump (bafilomycin) and cathepsin K. We found that bafilomycin and NS5818 dose dependently inhibited acidification of the osteoclastic resorption compartment and bone resorption. Inhibition of bone resorption by inhibition of acidification, but not cathepsin K inhibition, augmented osteoclast survival, which resulted in a 150 to 300% increase in osteoclasts compared to controls. We investigated the effect of inhibition of osteoclastic acidification in vivo by using the rat ovariectomy model with twice daily oral dosing of NS3696 at 50 mg/kg for 6 weeks. We observed a 60% decrease in resorption (DPYR), increased tartrate-resistant acid phosphatase levels, and no effect on bone formation evaluated by osteocalcin. We speculate that attenuated acidification inhibits dissolution of the inorganic phase of bone and results in an increased number of nonresorbing osteoclasts that are responsible for the coupling to normal bone formation. Thus, we suggest that acidification is essential for normal bone remodeling and that attenuated acidification leads to uncoupling with decreased bone resorption and unaffected bone formation.
BACKGROUND: Adrenomedullin (AM) is a potent vasodilator and natriuretic peptide produced in the heart, but controversy persists regarding its cardiac effects. We explored the potential role of AM on cardiac function and remodeling by direct recombinant adenoviral AM gene delivery into the anterior wall of the left ventricle (LV). METHODS: AM was overexpressed in healthy rat hearts and in hearts during the remodeling process in response to pressure overload and myocardial infarction. The AM effects were analysed with echocardiography and in an isolated perfused rat heart preparation. The expression of AM and the activation of underlying signaling pathways were also investigated. RESULTS: AM mRNA increased by 20.9-fold (p
To evaluate the role of lymphocytes in the pathogenesis of allergic bronchoconstriction, we investigated whether allergic airway responses are adoptively transferred by antigen-primed lymphocytes in Brown Norway (BN) rats. Animals were actively sensitized to ovalbumin (OA) or sham sensitized, and 14 d later mononuclear cells (MNCs) were isolated from intrathoracic lymph nodes, passed through a nylon wool column, and transferred to naive syngeneic rats. Recipients were challenged with aerosolized OA or bovine serum albumin (BSA) (5% wt/vol) and analyzed for changes in lung resistance (RL), airway responsiveness to inhaled methacholine (MCh), and bronchoalveolar lavage (BAL) cells. Recipients of MNCs from sensitized rats responded to OA inhalation and exhibited sustained increases in RL throughout the 8-h observation period, but without usual early airway responses. Recipients of sham-sensitized MNCs or BSA-challenged recipients failed to respond to antigen challenge. At 32 h after OA exposure, airway responsiveness to MCh was increased in four of seven rats that had received sensitized MNCs (p = 0.035). BAL eosinophils increased at 32 h in the recipients of both sensitized and sham-sensitized MNCs. However, eosinophil numbers in BAL were inversely correlated with airway responsiveness in the recipients of sensitized MNCs (r = -0.788, p = 0.036). OA-specific immunoglobulin E (IgE) was undetectable by enzyme-linked immunosorbent assay (ELISA) or passive cutaneous anaphylaxis (PCA) in recipient rats following adoptive transfer. In conclusion, allergic late airway responses (LAR) and cholinergic airway hyperresponsiveness, but not antigen-specific IgE and early responses, were adoptively transferred by antigen-primed lymphocytes in BN rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Increasing evidence suggests that alveolar macrophages (AM) are involved in asthma pathogenesis. To better understand the role that these cells play, we investigated the capacity of AM from allergy-resistant rat, Sprague Dawley (SD), to modulate airway hyperresponsiveness of allergy-susceptible rat, Brown Norway (BN). AM of ovalbumin (OVA)-sensitized BN rats were eliminated by intratracheal instillation of liposomes containing clodronate. AM from OVA-sensitized SD rats were transferred into AM-depleted BN rats 24 h before allergen challenge. Airway responsiveness to methacholine was measured the following day. Instillation of liposomes containing clodronate in BN rats eliminated 85% AM after 3 d compared with saline liposomes. Methacholine concentration needed to increase lung resistance by 200% (EC200RL) was significantly lower in OVA-challenged BN rats (27.9 +/- 2.8 mg/ml) compared with SD rats (63.9 +/- 8.6 mg/ml). However, when AM from SD rats were transferred into AM-depleted BN rats, airway responsiveness (64.0 +/- 11.3 mg/ml) was reduced to the level of naïve rats (54.4 +/- 3.7 mg/ml) in a dose-dependent manner. Interestingly, transfer of AM from BN rats into SD rats did not modulate airway responsiveness. To our knowledge, this is the first direct evidence showing that AM may protect against the development of airway hyperresponsiveness.
Comment In: Am J Respir Cell Mol Biol. 2004 Jul;31(1):1-215208095
Comment In: Am J Respir Cell Mol Biol. 2004 Jul;31(1):3-715208096
The levels of adrenomedullin (ADM), a newly discovered vasodilating and natriuretic peptide, are elevated in plasma and ventricular myocardium in human congestive heart failure suggesting that cardiac synthesis may contribute to the plasma concentrations of ADM. To examine the time course of induction and mechanisms regulating cardiac ADM gene expression, we determined the effect of acute and short-term cardiac overload on ventricular ADM mRNA and immunoreactive ADM (ir-ADM) levels in conscious rats. Acute pressure overload was produced by infusion of arginine8-vasopressin (AVP, 0.05 microg/kg/min, i.v.) for 2 h into 12-week-old hypertensive TGR(mREN-2)27 rats and normotensive Sprague-Dawley (SD) rats. Hypertension and marked left ventricular hypertrophy were associated with 2.2-times higher ir-ADM levels in the left ventricular epicardial layer (178 +/- 36 vs. 81 +/- 23 fmol/g, P
We examined whether adrenomedullin, a vasoactive peptide expressed in the heart, modulates the increase in blood pressure, changes in systolic and diastolic function, and left ventricular hypertrophy produced by long-term administration of ANG II or norepinephrine in rats. Subcutaneous administration of adrenomedullin (1.5 microg.kg(-1).h(-1)) for 1 wk inhibited the ANG II-induced (33.3 microg.kg(-1).h(-1) sc) increase in mean arterial pressure by 67% (P
Brown Norway rats are widely used as a model of asthma, whereas Sprague Dawley rats do not develop allergic reactions under the same conditions. Given the importance of alveolar macrophages (AM) in down-regulating cellular immune responses in the lung, we postulated that the different susceptibilities in the development of airway allergic reactions in these rat strains may be related to functional differences in their AM. We investigated the production of important mediators in asthma, namely tumour necrosis factor (TNF), interleukin-10 (IL-10), IL-12, IL-13, nitric oxide (NO) and macrophage inflammatory protein-1alpha (MIP-1alpha), by AM of unsensitized Sprague Dawley and Brown Norway rats. AM were purified by adherence and stimulated with OX8 (anti-CD8 antibody) or LPS. OX8 stimulation significantly increased the release of TNF, IL-10 and NO in both strains of rats, whereas MIP-1alpha and IL-12 release were increased in Brown Norway rats only. Interestingly, stimulated AM from Sprague Dawley rats released significantly more TNF and less IL-10, IL-12, IL-13, MIP-1alpha and NO compared with AM from Brown Norway rats. These differences were also observed at the mRNA level, except for TNF. Thus, AM from Brown Norway and Sprague Dawley rats are functionally different. Furthermore, LPS- and OX8-stimulated AM from Brown Norway rats produce more Th2 type cytokines (IL-10 and IL-13) than AM from Sprague Dawley rats, suggesting that these cells may play an important role in creating a cytokine milieu that may favour the development of allergic reactions.
OBJECTIVE. To assess the influence of protein malnutrition on anastomotic healing in rat small bowel with or without chronic radiation damage. DESIGN. Controlled laboratory study. SETTING. University hospital, Sweden. MATERIAL. 60 male Sprague-Dawley rats. INTERVENTION. A short segment of the distal ileum was exteriorised and irradiated (n = 30) or only exposed (n = 30), and 20 weeks later an anastomosis was made within this segment. Two weeks before anastomosis half of the animals in each group received rat chow in which the protein content had been reduced to 25%; standard rat chow was given to the remaining animals. MAIN OUTCOME MEASUREMENTS. Weight changes, anastomotic bursting strength, amount of perianastomotic hydroxyproline, and number of anastomotic complications. RESULTS. 13 animals in the irradiated group and 11 animals in the non-irradiated group died of intestinal obstruction or respiratory distress leaving 17 and 19 animals that could be evaluated. Body weight was significantly reduced in animals with protein restriction (p