Genetic background, sex, age and pacing cycle length affect left atrial electrophysiology in Langendorff-perfused isolated murine hearts

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
J Obergassel ◽  
M O'Reilly ◽  
C O'Shea ◽  
S.N Kabir ◽  
L.C Sommerfeld ◽  
...  
Keyword(s):  
Body Weight ◽  
Genetic Background ◽  
Left Atrial ◽  
Coronary Flow ◽  
Weight Ratio ◽  
British Heart Foundation ◽  
Funding Source ◽  
Body Weight Ratio ◽  
Experimental Conditions ◽  
Heart Foundation

Abstract Background Studying cardiac electrophysiology in isolated perfused beating murine hearts is a well-established method. The ranges of normal values for left atrial (LA) action potential durations (LA-APD), activation times (LA-AT) and effective refractory periods (atrial ERP) in murine wildtype (WT) are not well known. Purpose This study aimed to establish reference values for LA-APD, LA-AT and atrial ERP and to identify the influence of genetic background, sex and age on these electrophysiological parameters in WT mice. Method We combined results from isolated beating heart Langendorff experiments carried out in WT mice between 2005 and 2019 using an octopolar catheter inserted into the right atrium and a monophasic action potential electrode recording from the LA epicardium. Electrophysiological parameters (LA-APD at 50%, 70%, 90% repolarization (APD50, APD70, APD90), LA-AT and atrial ERP) at different pacing cycle lengths (PCL) were summarized. We analysed effects of PCL, genetic background, age, gender, heart weight to body weight ratio (HW/BW), LA weight to body weight ratio (LAW/BW) as well as coronary flow and temperature as experimental conditions. Results Electrophysiological parameters from 222 isolated hearts (114 female, mean age 6.6±0.25 months, range 2.47–17.7 months) of different backgrounds (77 C57BL/6, 23 FVB/N, 33 MF1, 69 129/Sv and 20 Swiss agouti) were combined. Coronary flow rate, flow temperature and start of isolation to cannulation time were constant experimental conditions over the timespan of experiments. LA-APD was longer while LA-AT decreased with longer PCL throughout all genetic backgrounds (Figure 1A). Genetic background showed strong effects on all electrophysiological parameters. LA-APD70 and atrial ERP were significantly shorter in Swiss agouti background compared to others. LA-APD70 was also significantly prolonged in 129/Sv background compared to MF1 (Figure 1B). LA activation was delayed in 129/Sv compared to other backgrounds (Figure 1C). Atrial ERP was longer in FVB/N compared to other backgrounds. Atrial ERP was also significantly prolonged (+ 3.4 ms, + 13.5%) in female mice compared to males (Figure 1D). Age effects were compared in groups. Atrial ERP was significantly longer in mice younger than 3 months compared to older mice (Figure 1E). Conclusion This dataset summarises left atrial electrophysiological parameters in the beating mouse heart and can serve as a reference for design and interpretation of electrophysiological experiments in murine models of commonly used genetic backgrounds. We demonstrate that PCL, genetic background, age and gender affect atrial electrophysiological parameters. Awareness of these will support successful experimental design. Figure 1 Funding Acknowledgement Type of funding source: Public grant(s) – EU funding. Main funding source(s): This work was partially supported by the European Commission (grant agreements no. 633196 [CATCH ME]) to LF and PK, Deutsche Forschungsgemeinschaft DFG FA413, British Heart Foundation (FS/13/43/30324 to LF and PK; AA/18/2/34218 to LF and PK).The Institute of Cardiovascular Sciences has received the British Heart Foundation (BHF) Accelerator Award (AA/18/2/34218). JO has received financial support for abroad studies within his scholarship of the Studienstiftung des deutschen Volkes (German Academic Scholarship Foundation).

1272Effect of age, genetic background and experimental conditions on left atrial monophasic action potential duration, effective refractory period and activation time in Langendorff-perfused murine hearts

EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
J Obergassel ◽  
S N Kabir ◽  
M O"reilly ◽  
L C Sommerfeld ◽  
C O"shea ◽  
...  
Keyword(s):  
Body Weight ◽  
Action Potential ◽  
Genetic Background ◽  
Left Atrial ◽  
Coronary Flow ◽  
Weight Ratio ◽  
Monophasic Action Potential ◽  
Heart Weight ◽  
Body Weight Ratio ◽  
Experimental Conditions

Abstract Funding Acknowledgements Supported by EU [CATCH ME] 633196, British Heart Foundation FS/13/43/30324, AA/18/2/34218 LF, PK, DFG FA413 LF, Studienstiftung to JO. Background Studying cardiac electrophysiology in isolated perfused beating murine hearts is a well-established method. The range of normal values for left atrial action potential durations (LA-APD), activation times (LA-AT) and effective refractory periods (atrial ERP) in murine wildtype (WT) is not well known. Purpose This study aimed to establish reference values for LA-APD, LA-AT and atrial ERP and to identify factors that influence these electrophysiological parameters in wildtype (WT) mice. Method We combined results from isolated beating heart Langendorff experiments carried out in WT between 2005 and 2019 using an octopolar catheter inserted into the right atrium and a monophasic action potential electrode recording from the LA epicardium. Electrophysiological parameters (LA-APD at 50%, 70%, 90% repolarization (APD50, APD70, APD90), LA-AT and atrial ERP) at different pacing cycle lengths (PCL) were summarized. We analyzed effects of PCL, genetic background, age, gender, heart weight to body weight ratio (HW/BW), LA weight to body weight ratio (LAW/BW) as well as coronary flow and temperature as experimental conditions. Results Electrophysiological parameters from 222 isolated hearts (114 female, mean age 6.6 ± 0.25 months, range 2.47-17.7 months) of different backgrounds (77 C57BL/6, 23 FVB/N, 33 MF1, 69 129/Sv and 20 Swiss agouti) were combined. Coronary flow rate, flow temperature and start of isolation to cannulation time were constant experimental conditions over the timespan of experiments. LA-APD was longer while LA-AT decreased with longer PCL throughout all genetic backgrounds (Figure 1A). Genetic background showed strong effects on all electrophysiological parameters. LA activation was delayed in 129/Sv compared to other backgrounds (Figure 1D). LA-APD70 and atrial ERP were significantly shorter in Swiss agouti background compared to others. LA-APD70 was also significantly prolonged in 129/Sv background compared to MF1 (Figure 1C). Atrial ERP was longer in FVB/N compared to other backgrounds. Age effects were compared in groups. Atrial ERP was significantly longer in mice ≤ 3 months compared to all older mice. Atrial ERP was also significantly prolonged (+ 3.4ms, + 13.5%) in female mice compared to males (Figure 1B). Conclusion This dataset summarizes left atrial electrophysiological parameters in the beating mouse heart and can serve as a reference for design and interpretation of electrophysiological experiments in murine models of commonly used genetic backgrounds. We confirm that cycle length, genetic background, age and gender affect atrial electrophysiological parameters. Awareness of these will support successful experimental design. Abstract Figure 1

Age-associated increase in rat ventricular ANP gene expression correlates with cardiac hypertrophy

1995 ◽  
Vol 269 (3) ◽  
pp. H1003-H1008 ◽  
Author(s):  
A. Younes ◽  
M. O. Boluyt ◽  
L. O'Neill ◽  
A. L. Meredith ◽  
M. T. Crow ◽  
...  
Keyword(s):  
Gene Expression ◽  
Body Weight ◽  
Cardiac Hypertrophy ◽  
Left Atrial ◽  
Northern Blot Analysis ◽  
Weight Ratio ◽  
Left Ventricular ◽  
Mrna Levels ◽  
Body Weight Ratio ◽  
Old Rats

Atrial natriuretic peptide (ANP), a cardiac-specific hormone, is stored in the atria and released in response to atrial stretch. During cardiac hypertrophy, ANP gene expression is markedly upregulated in the left ventricle (LV). Because the hearts of normotensive senescent rats exhibit left atrial (LA) and left ventricular (LV) hypertrophy and dilatation, we examined ANP mRNA levels by Northern blot analysis and ANP peptide concentrations by radioimmunoassay in atria, LVs, and plasma of rats at 2, 6, 18, and 22-24 mo of age. Compared with LVs of 6-mo-old rats, the LV-to-body weight ratio was elevated 30% by 18 mo of age, whereas levels of ANP mRNA were elevated twofold (not significant) and sevenfold (P < 0.05) in the LV of 18- and 22- to 24-mo-old rats, respectively. The concentration of immunoreactive ANP (ir-ANP) exhibited a four- to fivefold increase in LVs of 18- and 22- to 24-mo-old rats compared with values for 6-mo-old rats (43 +/- 4 pmol/g wet wt; means +/- SE). Among 18-and 22- to 24-mo-old rats a significant correlation was observed between ANP peptide concentration and LV hypertrophy (r 2 = 0.64). Levels of ANP mRNA and ir-ANP in the atria exhibited only modest changes with aging.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Creatine Alleviates Doxorubicin-Induced Liver Damage by Inhibiting Liver Fibrosis, Inflammation, Oxidative Stress, and Cellular Senescence

Nutrients ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 41
Author(s):  
Nouf Aljobaily ◽  
Michael J. Viereckl ◽  
David S. Hydock ◽  
Hend Aljobaily ◽  
Tsung-Yen Wu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Methylation ◽  
Body Weight ◽  
Liver Fibrosis ◽  
Liver Damage ◽  
Cellular Senescence ◽  
Weight Ratio ◽  
Mrna Levels ◽  
Body Weight Ratio ◽  
Chromosomal Stability

Background: Treatment with the chemotherapy drug doxorubicin (DOX) may lead to toxicities that affect non-cancer cells including the liver. Supplementing the diet with creatine (Cr) has been suggested as a potential intervention to minimize DOX-induced side effects, but its effect in alleviating DOX-induced hepatoxicity is currently unknown. Therefore, we aimed to examine the effects of Cr supplementation on DOX-induced liver damage. Methods: Male Sprague-Dawley rats were fed a diet supplemented with 2% Cr for four weeks, 4% Cr for one week followed by 2% Cr for three more weeks, or control diet for four weeks. Animals then received either a bolus i.p. injection of DOX (15 mg/kg) or saline as a placebo. Animals were then sacrificed five days-post injection and markers of hepatoxicity were analyzed using the liver-to-body weight ratio, aspartate transaminase (AST)-to- alanine aminotransferase (ALT) ratio, alkaline phosphatase (ALP), lipemia, and T-Bilirubin. In addition, hematoxylin and eosin (H&E) staining, Picro-Sirius Red staining, and immunofluorescence staining for CD45, 8-OHdG, and β-galactosidase were performed to evaluate liver morphology, fibrosis, inflammation, oxidative stress, and cellular senescence, respectively. The mRNA levels for biomarkers of liver fibrosis, inflammation, oxidative stress, and senescence-related genes were measured in liver tissues. Chromosomal stability was evaluated using global DNA methylation ELISA. Results: The ALT/AST ratio and liver to body weight ratio tended to increase in the DOX group, and Cr supplementation tended to attenuate this increase. Furthermore, elevated levels of liver fibrosis, inflammation, oxidative stress, and senescence were observed with DOX treatment, and Cr supplementation prior to DOX treatment ameliorated this hepatoxicity. Moreover, DOX treatment resulted in chromosomal instability (i.e., altered DNA methylation profile), and Cr supplementation showed a tendency to restore chromosomal stability with DOX treatment. Conclusion: The data suggest that Cr protected against DOX-induced hepatotoxicity by attenuating fibrosis, inflammation, oxidative stress, and senescence.

Exercise and clenbuterol as strategies to decrease the progression of muscular dystrophy in mdx mice

1996 ◽  
Vol 80 (3) ◽  
pp. 734-741 ◽  
Author(s):  
E. E. Dupont-Versteegden
Keyword(s):  
Body Weight ◽  
Muscular Dystrophy ◽  
Weight Ratio ◽  
Morphological Characteristics ◽  
Mdx Mice ◽  
Body Weight Ratio ◽  
Muscle Weight ◽  
Sedentary Group ◽  
Running Activity ◽  
Tetanic Tension

The effects of exercise and the combination of exercise and clenbuterol on progression of muscular dystrophy were studied in mdx mice. At 3 wk of age, mdx mice were randomly assigned to sedentary (MS), exercise (ME), or combined exercise and clenbuterol (MEC) groups. Clenbuterol was given in the drinking water (1.0-1.5 mg . kg body weight-1 . day-1), and exercise consisted of spontaneous running activity on exercise wheels. At 3 mo or 1 yr of age, ventilatory function, contractile properties, and morphological characteristics of the soleus (Sol) and diaphragm (Dia) muscles were measured. The mdx mice receiving clenbuterol ran less than the mice without clenbuterol. The combination of clenbuterol and exercise was associated with an increase in Sol muscle weight and a muscle weight-to-body weight ratio of 30-35% compared with the sedentary group and approximately 20% compared to exercise alone. Myosin and total protein concentrations of the Sol and Dia increased in the MEC group at 1 yr of age only. Normalized active tension was increased in the Dia at 1 yr of age in both the ME and MEC groups by approximately 30%. Absolute tetanic tension of the Sol was increased at both 3 mo and 1 yr of age in the MEC compared with the MS group. At 1 yr of age, there was an additional 23% increase compared with the ME group. Fatigability increased in the MEC group by approximately 25% in the Sol and Dia muscles at both ages compared with the MS and ME groups. Results indicate that exercise and exercise plus clenbuterol decrease the progression of muscular dystrophy. However, different mechanisms may be involved because the combination of clenbuterol and exercise resulted in increased fatigability and the development of deformities, whereas exercise alone did not. Therefore, clenbuterol may not be suitable for use in patients with muscular dystrophy.

A study on the safety evaluation of buphrenorphine administered through an autoinjector compared with manual injection using haematological and biochemical variables in rats

2016 ◽  
Vol 36 (9) ◽  
pp. 901-909 ◽  
Author(s):  
D Sheela ◽  
R Vijayaraghavan ◽  
S Senthilkumar
Keyword(s):  
Body Weight ◽  
Research Work ◽  
Safety Evaluation ◽  
Weight Ratio ◽  
The Body ◽  
Control Group ◽  
Body Weight Ratio ◽  
Significant Difference ◽  
Manual Group ◽  
Significant Change

Buprenorphine drug cartridge was made for autoinjector device for use in emergency and critical situations to reduce the morbidity and mortality. Water-filled cartridges were prepared and buprenorphine was injected aseptically in the cartridge, to make 0.05 and 0.10 mg/mL. Rats were injected intraperitoneally, buprenorphine (0.3 and 0.6 mg/kg), repeatedly with the autoinjector and compared with manual injection (7 days and 14 days) using various haematological and biochemical parameters. No significant change was observed in the body weight, organ to body weight ratio and haematological variables in any of the experimental groups compared with the control group. Except serum urea and aspartate aminotransferase, no significant change was observed in glucose, cholesterol, triglycerides, bilirubin, protein, albumin, creatinine, uric acid, alanine aminotransferase, gamma glutamyltransferase and alkaline phosphatase. The autoinjectors deliver the drugs with spray effect and force for faster absorption. In the present study, the autoinjector meant for intramuscular injection was injected intraperitoneally in rats, and the drug was delivered with force on the vital organs. No significant difference was observed in the autoinjector group compared to the manual group showing tolerability and safety of the buphrenorphine autoinjector. This study shows that buprenorphine autoinjector can be considered for further research work.

scholarly journals Protective Role of Pomegranate Peel Extract on Testis in Adult Male Rabbits Treated with Carbon Tetrachloride

2014 ◽  
Vol 38 (1) ◽  
pp. 74-82
Author(s):  
Wassan M. Hussen
Keyword(s):  
Body Weight ◽  
Olive Oil ◽  
Serum Cholesterol ◽  
Weight Ratio ◽  
Body Weight Ratio ◽  
Pomegranate Peel ◽  
Testosterone Concentration ◽  
Testicular Weight ◽  
Pomegranate Peel Extract ◽  
Peel Extract

The aim of the present study is to prepare ethanol extract of Pomegranate peel and the effects of this extract on testicular weight to body weight ratio, Serum cholesterol, testosterone concentration and histopathological changes of testes in rabbits treated with carbon tetrachloride (CCl4). Twenty four adult male rabbits were used. They were divided randomly into four equal groups. Animals were treated for 56 days as following: Rabbits of the 1st group were received 1 ml distal water orally once a day and olive oil 0.5 ml /kg B.W. I.P twice a week as control group. The second group were treated I.P with 500mg / kg B.W. of CCl4 mixing with equal volume of olive oil (0.5 ml/kg B.W.) twice a week (group T1). The third group was received pomegranate peel extract orally (100 mg/kg B.W) once a day and olive oil 0.5 ml /kg B.W. I.P twice a week (group T2). The fourth group were received pomegranate peel extract (100 mg/kg B.W) once a day oral I.P with 500 mg / kg B.W. of CCl4 mixing with equal volume of olive oil (o.5 ml/kg B.W.) twice a week (group T3). Blood samples were collected at (0, 14, 28, 42 and 56) days for measuring testosterone concentration, Serum cholesterol after treatments. Animals weighed and scarified and testis were removed and weighed, Samples of testis were taken for histopathological study. The results of the present study showed that treatment with pomegranate peel extract causes a significant (P>0.05) increase in testicular weight to body weight ratio. Also a significant (P>0.05) decreased of serum cholesterol and a significantly (P>0.05) elevation of testosterone concentration were observed. Histopathological examination of the testis was revealed that the extract of Pomegranate peel protect the testis against lesions caused by CCl4. In conclusion, Pomegranate peel extract could protect the tissue of testicles from CCl4 perhaps, by its anti-oxidative effect of pomegranate peel extract, hence eliminating the deleterious effects or toxic effect of CCl4.

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