Tissue hypoxygenation activates the adrenomedullin system in vivo

2000 ◽  
Vol 278 (2) ◽  
pp. R513-R519 ◽  
Author(s):  
Karl-Heinz Hofbauer ◽  
Boye L. Jensen ◽  
Armin Kurtz ◽  
Peter Sandner
Keyword(s):  
Intracellular Signaling ◽  
Messenger Rna ◽  
Rnase Protection Assay ◽  
Tissue Hypoxia ◽  
Mrna Abundance ◽  
Sprague Dawley ◽  
Rnase Protection ◽  
Sprague Dawley Rats ◽  
Intracellular Signaling Cascade

Our study aimed to investigate the influence of tissue hypoxygenation on the adrenomedullin (ADM) system in vivo. For this purpose, male Sprague-Dawley rats were exposed to normobaric hypoxia (8% oxygen) or to functional anemia [0.1% carbon monoxide (CO)] or to cobalt chloride (60 mg/kg) for 6 h. Messenger RNA levels for ADM and its receptor (ADM-R) were assessed in diverse organs by RNase protection assay. Additionally, ADM protein concentrations in these organs, as in plasma, were determined by a RIA. We found that ADM mRNA abundance increased in response to hypoxia and to CO inhalation up to 15-fold in all organs examined. Similarly, ADM-R mRNA abundance increased during hypoxia and CO inhalation in all organs examined with exception of the liver. The effects of hypoxia and of CO inhalation on ADM and ADM-R mRNAs were mimicked by injection of cobaltous chloride. Hypoxia also significantly increased ADM protein content in all organs, and plasma levels of ADM rose twofold in response to hypoxia and CO inhalation. These findings indicate that tissue hypoxia leads to a widespread activation of the ADM system, which comprises a parallel stimulation of ADM and ADM receptor mRNA as enhanced ADM protein synthesis and secretion. The ADM system may, therefore, play a significant role in the physiological response to tissue hypoxia. It appears that ADM and ADM-R belong to the family of classic oxygen-regulated genes, which are activated by a decrease of the pericellular oxygen tension through the same intracellular signaling cascade.

scholarly journals Effector Mechanisms of Protection againstPseudomonas aeruginosa Keratitis in Immunized Rats

2001 ◽  
Vol 69 (5) ◽  
pp. 3295-3304 ◽  
Author(s):  
A. Thakur ◽  
J. Kyd ◽  
M. Xue ◽  
M. D. P. Willcox ◽  
A. Cripps
Keyword(s):  
Molecular Mechanisms ◽  
Rnase Protection Assay ◽  
Interleukin 2 ◽  
Bacterial Count ◽  
Opportunistic Pathogen ◽  
Enzyme Linked Immunosorbent Assay ◽  
Sprague Dawley ◽  
Protection Assay ◽  
Rnase Protection ◽  
Sprague Dawley Rats

ABSTRACT Pseudomonas aeruginosa is an opportunistic pathogen which causes sight-threatening corneal infections in humans. The purpose of this study was to evaluate various immunization routes that may provide protection against Pseudomonas keratitis and to define the molecular mechanisms involved in the protection. Sprague-Dawley rats (10 to 12 weeks old) were immunized using paraformaldehyde-killed P. aeruginosa (strain 6206) via oral, nasal, and intra-Peyer's patch (IPP) routes followed by an ocular topical booster dose. Scratched corneas were challenged with an infective dose of P. aeruginosa. Following clinical examination, eyes were enucleated for histology, polymorphonuclear leukocyte (PMN) quantitation, bacterial count, enzyme-linked immunosorbent assay, and RNase protection assay. PMN infiltration was higher early (4 h) during the infection in immunized rats than in nonimmunized rats. Later during the infection, the number of PMNs diminished in immunized rats while in nonimmunized animals the number of PMNs continued to increase. Bacteria were cleared much faster from immunized groups than from the nonimmunized group, and the nasally immunized group had the most efficacious response among the immunized groups. Nasal and IPP immunization groups had increased cytokine expression of interleukin-2 (IL-2) and IL-5 and differed from each other for IL-6. All three immunized groups had significantly reduced IL-1β levels when compared with the nonimmunized rats and a significantly altered profile for CINC-1 expression. This study has shown that the route of immunization modulates the inflammatory response to ocular P. aeruginosa infection, thus affecting the severity of keratitis and adverse pathology, with nasal immunization being the most effective.

17β-Estradiol increases nitric oxide-dependent dilation in rat pulmonary arteries and thoracic aorta

2001 ◽  
Vol 280 (3) ◽  
pp. L555-L564 ◽  
Author(s):  
Rayna J. Gonzales ◽  
Benjimen R. Walker ◽  
Nancy L. Kanagy
Keyword(s):  
Nitric Oxide ◽  
Rnase Protection Assay ◽  
Pulmonary Arteries ◽  
Treated Group ◽  
Pulmonary Vasculature ◽  
Mrna Levels ◽  
Sprague Dawley ◽  
Rnase Protection ◽  
17Β Estradiol

Past studies have demonstrated that 17β-estradiol (E2β) increases endothelial nitric oxide (NO) synthase (eNOS) activity in uterine, heart, and skeletal muscle and in cultured human endothelial cells. However, little is known about E2β regulation of NO synthesis in the pulmonary vasculature. The present study evaluated E2β regulation of eNOS function in pulmonary arteries and thoracic aortas. We hypothesized that E2β upregulates vascular NO release by increasing eNOS expression. To test this, NO-dependent vasodilation was assessed in isolated perfused lungs and aortic rings from ovariectomized Sprague-Dawley rats treated for 1 wk with 20 μg/24 h of E2β or vehicle. Expression of eNOS was evaluated by Western blot and immunohistochemistry. Also, a RNase protection assay determined eNOS mRNA levels in lung and aortic homogenates from control and treated rats. Vasodilation to ionomycin in lungs from the E2β-treated group was enhanced compared with that in control animals. Endothelium-intact aortic rings from E2β-treated animals also demonstrated augmented endothelium-dependent dilation. Both responses were blocked with NOS inhibition. Immunostaining for eNOS was greater in pulmonary arteries and aortas from E2β-treated compared with control rats. However, mRNA levels did not differ between groups. Thus we conclude that in vivo E2β treatment augments endothelium-dependent dilation in aorta and lung, increasing expression of eNOS independently of sustained augmented gene transcription.

Hydroxysafflor Yellow A Attenuates Carbon Tetrachloride-Induced Hepatic Fibrosis in Rats by Inhibiting Erk5 Signaling

2012 ◽  
Vol 40 (03) ◽  
pp. 481-494 ◽  
Author(s):  
Ying-Bo Zhang ◽  
Han-Ying Dong ◽  
Xue-Ming Zhao ◽  
Li Fan ◽  
Yu Zou ◽  
...  
Keyword(s):  
Hepatic Fibrosis ◽  
Transforming Growth Factor Beta ◽  
Messenger Rna ◽  
Transforming Growth Factor ◽  
Stellate Cell ◽  
Sprague Dawley ◽  
Hydroxysafflor Yellow A ◽  
Sprague Dawley Rats ◽  
Polymerase Chain

Hepatic stellate cells (HSCs) undergo activation during the development of liver fibrosis. Transcription factor myocyte enhancer factor (MEF2) 2C plays a key role in this process. In the present study, we investigated the effect of hydroxysafflor yellow A (HSYA) on hepatic fibrosis and further investigated potential mechanisms in vivo. Sprague-Dawley rats were administered with CCl4 together with or without HYSA for 12 weeks. The effect of HYSA on hepatic fibrosis was evaluated using hematoxylin-eosin and Van Gieson staining. Messenger RNA expression was quantified by real-time polymerase chain reaction, and protein was quantified by Western blot or immunohistochemistry. Our results revealed that CCl4 treatment induced micronodular hepatic fibrosis with a pronounced deposition of collagen fibers. Treatment with HYSA resulted in a significant decrease in fibrosis, protein expression of α-SMA, and MEF-2C gene expression. This was accompanied by a decreased expression of Tβ-RI, Tβ-RII, MEKK3, MEK5, and phosphorylation of ERk5. HYSA alone had no effect on the measured parameters. Our findings demonstrate that HSYA protected, at least in part, the rat liver from CCl 4-caused fibrogenesis through inhibition of hepatic stellate cell (HSC) activation, attenuation of transforming growth factor beta (TGF-β) signaling. HSYA may become a novel and promising agent for the inhibition of hepatic fibrosis.

Toxicokinetic and Genotoxicity Study of NNK in Male Sprague-Dawley Rats Following Nose-Only Inhalation Exposure, Intraperitoneal Injection, and Oral Gavage

2021 ◽  
Author(s):  
Shu-Chieh Hu ◽  
Matthew S Bryant ◽  
Estatira Sepehr ◽  
Hyun-Ki Kang ◽  
Raul Trbojevich ◽  
...  
Keyword(s):  
Human Lung ◽  
Inhalation Exposure ◽  
Systemic Exposure ◽  
Sprague Dawley ◽  
Oral Gavage ◽  
Sd Rats ◽  
New Information ◽  
Sprague Dawley Rats ◽  
Tissue Specimens

Abstract The tobacco-specific nitrosamine NNK [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone] is found in tobacco products and tobacco smoke. NNK is a potent genotoxin and human lung carcinogen; however, there are limited inhalation data for the toxicokinetics (TK) and genotoxicity of NNK in vivo. In the present study, a single dose of 5x10−5, 5x10−3, 0.1, or 50 mg/kg body weight (BW) of NNK, 75% propylene glycol (vehicle control), or air (sham control) was administered to male Sprague-Dawley (SD) rats (9-10 weeks age) via nose-only inhalation (INH) exposure for 1 hour. For comparison, the same doses of NNK were administered to male SD rats via intraperitoneal (IP) injection and oral gavage (PO). Plasma, urine, and tissue specimens were collected at designated timepoints and analyzed for levels of NNK and its major metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and tissue levels of DNA adduct O6-methylguanine by LC/MS/MS. TK data analysis was performed using a non-linear regression program. For the genotoxicity subgroup, tissues were collected at 3 hours post-dosing for comet assay analysis. Overall, the TK data indicated that NNK was rapidly absorbed and metabolized extensively to NNAL after NNK administration via the three routes. The IP route had the greatest systemic exposure to NNK. NNK metabolism to NNAL appeared to be more efficient via INH than IP or PO. NNK induced significant increases in DNA damage in multiple tissues via the three routes. The results of this study provide new information and understanding of the toxicokinetics and genotoxicity of NNK.

scholarly journals Pharmacological comparison of four biopolymeric natural gums as hemostatic agents for management of bleeding wounds: preliminary in vitro and in vivo results

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Himanshu Kushwah ◽  
Nidhi Sandal ◽  
Meenakshi Chauhan ◽  
Gaurav Mittal
Keyword(s):  
Xanthan Gum ◽  
Guar Gum ◽  
Human Lymphocytes ◽  
Sprague Dawley ◽  
Gum Tragacanth ◽  
Civilian Trauma ◽  
Sprague Dawley Rats ◽  
Cytotoxicity Studies

Abstract Background Uncontrolled bleeding is one of the primary reasons for preventable death in both civilian trauma and military battle field. This study evaluates in vitro and in vivo hemostatic potential of four biopolymeric natural gums, namely, gum tragacanth, guar gum, xanthan gum, and gum acacia. In vitro evaluation of whole blood clotting time and erythrocyte agglutination assay were carried out. In vitro cytotoxicity studies with respect to each gum were done in human lymphocytes to ascertain percent cell viability. In vivo hemostatic potential of each gum (as sponge dressing and powder form) was evaluated in Sprague Dawley rats using tail bleeding assay and compared with commercially available hemostatic sponge. Other important parameters like (a) time taken for complete hemostasis, (b) amount of blood absorbed, (c) adherence strength of developed hemostatic dressing(s), (d) incidence of re-bleeding, and (e) survival of animals were also studied. Results Of the four test gums studied, xanthan gum (@3mg/ml of blood) and gum tragacanth (@35mg/ml of blood) were able to clot blood in least time (58.75±6.408 s and 59.00±2.082 s, respectively) and exhibited very good hemostatic potential in vitro. Except for xanthan gum, all other test gums did not exhibit any significant cytotoxicity at different time points till 24 h. In rat tail bleeding experiments, gum tragacanth sponge dressing and powder achieved hemostasis in least time (156.2±12.86 s and 76±12.55 s, respectively) and much earlier than commercially available product (333.3±38.84 s; p˂0.01). Conclusion Results indicate potential of gum tragacanth to be developed into a suitable hemostatic product.

Bioavailability in Vivo of Benzo[a]Pyrene Adsorbed to Diesel Particulate

1991 ◽  
Vol 7 (3) ◽  
pp. 125-139 ◽  
Author(s):  
David R. Bevan ◽  
David M. Ruggio
Keyword(s):  
Health Risks ◽  
Quantitative Description ◽  
Intratracheal Instillation ◽  
Direct Analysis ◽  
Sprague Dawley ◽  
Reasonable Estimate ◽  
Diesel Particulate ◽  
Sprague Dawley Rats

To evaluate health risks associated with exposure to particulates in the environment, it is necessary to quantify the bioavailability of carcinogens associated with the particulates. Direct analysis of bioavailability in vivo is most readily accomplished by adsorbing a radiolabeled form of the carcinogen to the particulate. A sam ple of native diesel particulate collected from an Oldsmobile die sel engine that contained 1.03 μ g benzo[ a] pyrene ( BaP)/ g particulate was supplemented with exogenous [ 3 H]- BaP to pro duce a particulate containing 2.62 μ g BaP/g. To insure that elu tion of BaP from native and [3 H] -BaP-supplemented particulate was similar, in vitro analyses were performed. When using phos pholipid vesicles composed of dimyristoylphosphatidylcholine (DMPC), 1.52% of total BaP was eluted from native particulate into the vesicles in 18 hrs; from [ 3 H] -BaP supplemented particu late, 1.68% was eluted. Using toluene as eluent, 2.55% was eluted from native particulate, and 8.25% from supplemented particulate, in 6 hrs. Supplemented particulate was then instilled intratracheally into male Sprague-Dawley rats and distribution of radioactivity was analyzed at selected times over 3 days. About 50% of radioactivity remained in lungs at 3 days following instil lation, with 30% being excreted into feces and the remainder dis tributed throughout the organs of the rats. To estimate the amount of radioactivity that entered feces through swallowing of a portion of the instilled dose, [3 H] -BaP-supplemented particu late was instilled intratracheally into rats that had a cannula sur gically implanted in the bile duct. Rate of elimination of radio activity into bile was monitored; 10.6% of radioactivity was re covered in 6 hr, an amount slightly lower than the 12.8% ex creted in 6 hrs into feces of animals with intact bile ducts. Our studies provide a quantitative description of the distribution of BaP and its metabolites following intratracheal instillation of diesel particulate. Because rates of elution of BaP in vitro are similar for native diesel particulate and particulate with supple mental [ 3H] -BaP, our results provide a reasonable estimate of the bioavailability in vivo of BaP associated with diesel particu late.

scholarly journals The in vivo Pig-a gene mutation assay is applied to study the genotoxicity of procarbazine hydrochloride in Sprague-Dawley rats

2016 ◽  
Vol 3 (4) ◽  
pp. 167-175 ◽  
Author(s):  
Jiang Pu ◽  
Yuanyuan Deng ◽  
Xiaoyan Tan ◽  
Gaofeng Chen ◽  
Cong Zhu ◽  
...  
Keyword(s):  
Gene Mutation ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Mutation Assay ◽  
Gene Mutation Assay

scholarly journals CCK-8 and CCK-58 differ in their effects on nocturnal solid meal pattern in undisturbed rats

2012 ◽  
Vol 303 (8) ◽  
pp. R850-R860 ◽  
Author(s):  
Miriam Goebel-Stengel ◽  
Andreas Stengel ◽  
Lixin Wang ◽  
Gordon Ohning ◽  
Yvette Taché ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Food Intake ◽  
Molecular Forms ◽  
Reduce Food Intake ◽  
Dark Phase ◽  
Sprague Dawley ◽  
Solid Meal ◽  
Sprague Dawley Rats ◽  
And Behavior

Various molecular forms of CCK reduce food intake in rats. Although CCK-8 is the most studied form, we reported that CCK-58 is the only detectable endocrine peptide form in rats. We investigated the dark-phase rat chow intake pattern following injection of CCK-8 and CCK-58. Ad libitum-fed male Sprague-Dawley rats were intraperitoneally injected with CCK-8, CCK-58 (0.6, 1.8, and 5.2 nmol/kg), or vehicle. Food intake pattern was assessed during the dark phase using an automated weighing system that allowed continuous undisturbed monitoring of physiological eating behavior. Both CCK-8 and CCK-58 dose dependently reduced 1-h, dark-phase food intake, with an equimolar dose of 1.8 nmol being similarly effective (−49% and −44%). CCK-58 increased the latency to the first meal, whereas CCK-8 did not. The intermeal interval was reduced after CCK-8 (1.8 nmol/kg, −41%) but not after CCK-58. At this dose, CCK-8 increased the satiety ratio by 80% and CCK-58 by 160%, respectively, compared with vehicle. When behavior was assessed manually, CCK-8 reduced locomotor activity (−31%), whereas grooming behavior was increased (+59%). CCK-58 affected neither grooming nor locomotor activity. In conclusion, reduction of food intake by CCK-8 and CCK-58 is achieved by differential modulation of food intake microstructure and behavior. These data highlight the importance of studying the molecular forms of peptides that exist in vivo in tissue and circulation of the animal being studied.

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