scholarly journals Analysis of changes in the rat cardiovascular system under the action of lead intoxication and muscular exercise

2021 ◽  
Vol 100 (12) ◽  
pp. 1467-1474
Author(s):  
Svetlana V. Klinova ◽  
Ilzira A. Minigalieva ◽  
Yuri L. Protsenko ◽  
Marina P. Sutunkova ◽  
Iuliia V. Ryabova ◽  
...  
Keyword(s):  
Physical Exercise ◽  
Polyacrylamide Gel Electrophoresis ◽  
Male Rats ◽  
Lead Intoxication ◽  
Strength Development ◽  
Muscle Exercise ◽  
Sliding Velocity ◽  
Shortening Velocity ◽  
In Vitro Motility Assay ◽  
Thin Filaments

Introduction. One of the risk factors for cardiovascular diseases is the toxic metal pollution of the industrial area and the environment. Lead is the most critical of toxic metals. In industrial conditions, the body’s exposure to harmful substances is often combined with muscular work of varying severity. It has not been studied enough how these combinations influence the development of pathological processes associated with harmful exposure. Materials and methods. The subchronic experiment was carried out on white outbred male rats for six weeks. Intoxication was simulated by repeated intraperitoneal injections of lead acetate three times a week. Running was chosen to model the muscle exercise at a 25 m/min speed for 10 minutes 5 days a week. We performed biochemical and electrocardiographic studies. Blood pressure parameters were recorded. Muscle contractility was studied on isolated multicellular preparations of the right ventricular myocardium in isometric and physiological contraction modes. The ratio of myosin heavy chains was determined by the polyacrylamide gel electrophoresis. The sliding velocity of reconstituted thin filaments on myosin using an in vitro motility assay. Results. Physical exercise under lead intoxication normalized the level of calcium and the angiotensin-converting enzyme activity in the blood serum, the voltage of the isoelectric line and the amplitude of the T wave on the electrocardiogram. The combined action of lead and physical exercise showed an increase in the creatinine kinase-MB level. We found that the effect of exercise under lead intoxication on myocardial contractility was ambiguous. The maximum isotonic shortening velocity in trabeculae was normalized, but the maximum rate of strength development in the isometric mode in the papillary muscles decreased to a greater extent than under lead intoxication. The maximum sliding velocity of reconstituted thin filaments and myosin and the heavy chain ratio was partly normalized. Conclusion. In general, muscle exercise attenuated the lead cardiotoxic effects.

scholarly journals Cardioinotropic Effects in Subchronic Intoxication of Rats with Lead and/or Cadmium Oxide Nanoparticles

2021 ◽  
Vol 22 (7) ◽  
pp. 3466
Author(s):  
Svetlana V. Klinova ◽  
Boris A. Katsnelson ◽  
Ilzira A. Minigalieva ◽  
Oksana P. Gerzen ◽  
Alexander A. Balakin ◽  
...  
Keyword(s):  
Cadmium Oxide ◽  
Male Rats ◽  
Sliding Velocity ◽  
Muscle Type ◽  
In Vitro Motility Assay ◽  
Thin Filaments ◽  
In Vitro Motility ◽  
Toxic Impact ◽  
Cdo Nanoparticles

Subchronic intoxication was induced in outbred male rats by repeated intraperitoneal injections with lead oxide (PbO) and/or cadmium oxide (CdO) nanoparticles (NPs) 3 times a week during 6 weeks for the purpose of examining its effects on the contractile characteristics of isolated right ventricle trabeculae and papillary muscles in isometric and afterload contractions. Isolated and combined intoxication with these NPs was observed to reduce the mechanical work produced by both types of myocardial preparation. Using the in vitro motility assay, we showed that the sliding velocity of regulated thin filaments drops under both isolated and combined intoxication with CdO–NP and PbO–NP. These results correlate with a shift in the expression of myosin heavy chain (MHC) isoforms towards slowly cycling β–MHC. The type of CdO–NP + PbO–NP combined cardiotoxicity depends on the effect of the toxic impact, the extent of this effect, the ratio of toxicant doses, and the degree of stretching of cardiomyocytes and muscle type studied. Some indices of combined Pb–NP and CdO–NP cardiotoxicity and general toxicity (genotoxicity included) became fully or partly normalized if intoxication developed against background administration of a bioprotective complex.

scholarly journals CHANGES OF MYOCARDIUM CONTRACTILITY ASSOCIATED WITH A SUBCHRONIC LEAD INTOXICATION IN RATS

2020 ◽  
Vol 99 (2) ◽  
pp. 193-199
Author(s):  
Svetlana V. Klinova ◽  
Y. L. Protsenko ◽  
O. N. Lookin ◽  
A. A. Balakin ◽  
L. V. Nikitina ◽  
...  
Keyword(s):  
Contractile Function ◽  
Intraperitoneal Administration ◽  
Male Rats ◽  
Lead Intoxication ◽  
Mechanical Activity ◽  
Papillary Muscles ◽  
Sliding Velocity ◽  
In Vitro Motility Assay ◽  
In Vitro Motility

Introduction. There is a high chance of a link between cardiovascular conditions and occupational or environmental exposure to lead. Taking into account the peculiarities of lead intoxication and the metal common occurrence it appeared to necessarily prove further experimental research of lead cardiotoxicity. Material and methods. After repeated intraperitoneal administration of sublethal doses of lead acetate to outbred male rats 3 times a week for 5 weeks, there was obtained the moderately pronounced subchronic lead intoxication manifested by some characteristic features. Cardiotoxic effects on myocardial contractility were studied by the analysis of the mechanical activity of isolated preparations of right ventricular trabeculae and papillary muscles contracting in isotonic and physiological modes of loading. Myocardial contractile function was also studied at the molecular level by measuring the sliding velocity of reconstructed thin filaments over myosin. Results. In papillary muscles lead intoxication led to a decrease in the maximal rate of isotonic shortening for all afterloads and a decrease in the thin filament sliding velocity in the in vitro motility assay. The same type of muscle from lead-exposed rats displayed marked changes in most of the main characteristics of afterload contraction-relaxation cycles, but in trabeculae, these changes were less pronounced. The reported changes were attenuated to some extent in rats similarly exposed to lead while being treated with a Ca-containing bio protector. The amount of work produced by both muscle preparations was unchanged under lead intoxication over the entire range of afterloads, which is an evidence of adaptation to the production of adequate mechanical work despite resulting contractility disturbances. Conclusions. 1. Subchronic lead intoxication was shown to cause contractile dysfunction of rat myocardium. In papillary muscles the alterations were observed more than in trabeculae. The changes in contractile proteins corresponded with those seen in myocardium structures. 2. The reported changes were attenuated to some extent in rats being treated with a Ca-containing bio protector.

Shortening velocity and ATPase activity of rat skeletal muscle fibers: effects of endurance exercise training

1994 ◽  
Vol 266 (6) ◽  
pp. C1699-C1713 ◽  
Author(s):  
J. M. Schluter ◽  
R. H. Fitts
Keyword(s):  
Atpase Activity ◽  
Endurance Exercise ◽  
Citrate Synthase ◽  
Fiber Type ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Treadmill Running ◽  
Type I ◽  
Marker Enzyme ◽  
Shortening Velocity

Mechanical properties were measured in single skinned fibers from rat hindlimb muscle to test the hypothesis that the fast type IIb fiber exhibits a higher maximal shortening velocity (Vo) than the fast type IIa fiber and that the difference is directly attributable to a higher myofibrillar adenosinetriphosphatase (ATPase) activity in the type IIb fiber. Additional measurements were made to test the hypotheses that regular endurance exercise increases and decreases the Vo of the type I and IIa fiber, respectively, and that the altered Vo is associated with a corresponding change in the fiber ATPase activity. Rats were exercised by 8-12 wk of treadmill running for 2 h/day, 5 day/wk, up a 15% grade at a speed of 27 m/min. Fiber Vo was determined by the slack test, and the ATPase was measured fluorometrically in the same fiber. The myosin isozyme profile of each fiber was subsequently determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The mean +/- SE Vo (7.9 +/- 0.22 fiber lengths/s) of the type IIb fiber was significantly greater than the type IIa fiber (4.4 +/- 0.21 fiber lengths/s), and the higher Vo was associated with a higher ATPase activity (927 +/- 70 vs. 760 +/- 60 microM.min-1.mm-3). The exercise program induced cardiac hypertrophy and an approximately twofold increase in the mitochondrial marker enzyme citrate synthase. Exercise had no effect on fiber diameter or peak tension per cross-sectional area in any fiber type, but, importantly, it significantly increased (23%) both the Vo and the ATPase activity of the slow type I fiber of the soleus.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals β-endorphin response to aerobic and anaerobic exercises in Wistar male rats

2020 ◽  
Vol 29 (3) ◽  
pp. 245-9
Author(s):  
Rostika Flora ◽  
Mohammad Zulkarnain ◽  
Sukirno
Keyword(s):  
Physical Exercise ◽  
Aerobic Exercise ◽  
Brain Tissue ◽  
Exercise Group ◽  
Anaerobic Exercise ◽  
Treadmill Running ◽  
Male Rats ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Aerobic And Anaerobic

BACKGROUND Physical exercise is strongly associated with the release of β-endorphin. It is assumed that the type and intensity of physical exercise contributes to the release of β-endorphin. This study aimed to compare levels of β-endorphin in brain tissue in response to aerobic and anaerobic physical exercise. METHODS This study was an experimental laboratory study using 35 male Wistar rats divided into one control group and two physical exercise treatment groups: aerobic and anaerobic. Physical exercise was conducted on an animal treadmill running at aspeed of 20 m/min for 30 min of aerobic exercise and 35 m/min with 1-min intervals every 5 min for 20 min for anaerobic exercises. Each aerobic and anaerobic exercise group was furtherly classified into three subgroups (1×/week, 3×/week, and 7×/week). β-endorphin levels were determined using enzyme-linked immunosorbent assay. The data were analyzed using independent t-test and one-way analysis of variance. RESULTS The highest mean of β-endorphin level was found in the weekly exercise (54.45 [1.41] pg/ml) of aerobic exercise group and daily exercise (70.50 [11.67] pg/ml) of anaerobic exercise group. Mean of β-endorphin level in control group was 33.34 (3.54) pg/ml. A significant increased of β-endorphin mean level (p<0.001) was found in all aerobic and anaerobic exercise groups except the aerobic exercise 7×/week group(37.37 [6.30] pg/ml) compared to control. CONCLUSIONS Both aerobic and anaerobic physical exercise conducted for 6 weeks could increase the level of β-endorphin in brain tissue.

Abstract WP153: Post-Stroke Physical Exercise Improves Cognition in Middle-Aged Female Rats

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Sharnikha Saravanan ◽  
Weizhao Zhao ◽  
Kunjan R Dave ◽  
Miguel A Perez-Pinzon ◽  
Ami P Raval
Keyword(s):  
Enzyme Activity ◽  
Physical Exercise ◽  
Cognitive Decline ◽  
Fear Conditioning ◽  
Enzyme Activities ◽  
Female Rats ◽  
Male Rats ◽  
Mitochondrial Enzyme ◽  
Post Stroke ◽  
Activity Measurements

Background: A woman’s risk of a stroke increases exponentially following the onset of menopause, andpost-stroke cognitive decline is a significant consequence of stroke survivors. Our earlier study demonstrated that physical exercise (PE) reduced post-stroke brain injury and improved cognitive functions in male rats. The focus of our study is on the improvement of post-stroke cognitive function in female rats. Methods: Reproductively senescent Sprague-Dawley female rats were exposed to transient middle cerebral artery occlusion (tMCAO; 90 min) and randomly assigned to either PE or sham-PE groups. After 3-5 days, rats underwent sham-PE (0m/min speed) or PE (15m/min speed) for 30 mins either every day (continuous) or alternate day for five times on treadmill. The rats that underwent the alternate day paradigm were treated with ER-β agonist (DPN; 1mg/kg) or vehicle-DMSO immediately following PE/sham-PE sessions to determine the synergistic effect. Twenty-one days after the last PE/sham-PE, rats were tested for hippocampal-dependent contextual fear conditioning and freeze time was measured. Rat brains were processed for histology and infarct area was measured with MCID software. From a separate cohort of rat subjected to PE or sham-PE, brain tissue was harvested for various biochemical assays and mitochondrial enzyme activity measurements. Results: Post-tMCAO continuous PE did not reduce ischemic damage. However, alternate PE regimen with or without ER-β agonist reduced infract volume by 20% (p < 0.05) and 23% (p < 0.05), respectively as compared to no-PE. Similarly, alternate PE showed increased freezing on the second day of fear conditioning by 15% (p < 0.05), indicating improved spatial memory. Individual mitochondrial complex I, II, III and IV enzyme activity measurements demonstrated significant improvement in complex III-IV enzyme activities in the alternate PE treated group as compared to sham-PE. Conclusion: An alternate day PE paradigm and ER-β activation improves post-stroke mitochondrial enzyme activities and cognition in reproductively senescent female rats. Future studies delineating underlying mechanism could help identify therapies to prevent/reduce cognitive decline in menopausal female stroke patients.

scholarly journals Effect of hindlimb unweighting on single soleus fiber maximal shortening velocity and ATPase activity

1993 ◽  
Vol 74 (6) ◽  
pp. 2949-2957 ◽  
Author(s):  
K. S. McDonald ◽  
R. H. Fitts
Keyword(s):  
Atpase Activity ◽  
Soleus Muscle ◽  
Time Course ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Maximal Velocity ◽  
Shortening Velocity ◽  
Hindlimb Unweighting ◽  
Fast Myosin ◽  
Highly Correlated

This study characterizes the time course of change in single soleus muscle fiber size and function elicited by hindlimb unweighting (HU) and analyzes the extent to which varying durations of HU altered maximal velocity of shortening (Vo), myofibrillar adenosinetriphosphatase (ATPase), and relative content of slow and fast myosin in individual soleus fibers. After 1, 2, or 3 wk of HU, soleus muscle bundles were prepared and stored in skinning solution at -20 degrees C. Single fibers were isolated and mounted between a motor arm and a transducer, and fiber force, Vo, and ATPase activity were measured. Fiber myosin content was determined by one-dimensional sodium dodecyl sulfate- (SDS) polyacrylamide gel electrophoresis. After 1, 2, and 3 wk of HU, soleus fibers exhibited a progressive reduction in fiber diameter (16, 22, and 42%, respectively) and peak force (42, 48, and 72%, respectively). Peak specific tension was significantly reduced after 1 wk of HU (18%) and showed no further change in 2–3 wk of HU. During 1 and 3 wk of HU, fiber Vo and ATPase showed a significant increase. By 3 wk, Vo had increased from 1.32 +/- 0.04 to 2.94 +/- 0.17 fiber lengths/s and fiber ATPase from 291 +/- 16 to 1,064 +/- 128 microM.min-1 x mm-3. The percent fibers expressing fast myosin heavy chain increased from 4% to 29% by 3 wk of HU, and Vo and ATPase activity within a fiber were highly correlated.(ABSTRACT TRUNCATED AT 250 WORDS)

Sliding velocity of isolated rabbit cardiac myosin correlates with isozyme distribution

1992 ◽  
Vol 263 (2) ◽  
pp. H464-H472 ◽  
Author(s):  
H. Yamashita ◽  
S. Sugiura ◽  
T. Serizawa ◽  
T. Sugimoto ◽  
M. Iizuka ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Motility Assay ◽  
Cardiac Myosin ◽  
Sliding Velocity ◽  
In Vitro Motility Assay ◽  
In Vitro Motility ◽  
Actin Cables

To investigate the relationship between the mechanical and biochemical properties of cardiac myosin, the sliding velocity of isolated cardiac myosin obtained from both euthyroid and hyperthyroid rabbits on actin cables was measured with an in vitro motility assay system. Ten rabbits (T) were treated with L-thyroxine to induce hyperthyroidism, and eight nontreated animals (N) were used as controls. Myosin was purified from the left ventricles of anesthetized animals. Myosin isozyme content was analyzed by the pyrophosphate gel electrophoresis method, and myosin adenosinetriphosphatase (ATPase) activity was determined on the same sample. Long well-organized actin cables of green algae, Nitellopsis, were used in the in vitro motility assay. Small latex beads were coated with purified cardiac myosin and introduced onto the Nitellopsis actin cables. Active unidirectional movement of the beads on the actin cables was observed under a photomicroscope, and the velocity was measured. The velocity was dependent on ATP concentrations, and the optimal pH for bead movement was approximately 7.0-7.5. The mean velocity was higher in T than in N (0.66 +/- 0.12 vs. 0.32 +/- 0.09 micron/s, P less than 0.01). Both Ca(2+)-activated ATPase activity and the percentage of alpha-myosin heavy chain were also higher in T than in N (0.691 +/- 0.072 vs. 0.335 +/- 0.072 microM Pi.mg-1.min-1, P less than 0.01, and 79 +/- 12 vs. 26 +/- 7%, P less than 0.01, respectively). The velocity of myosin closely correlated with both Ca(+2)-activated myosin ATPase activity (r = 0.87, P less than 0.01) and the percentage of alpha-myosin heavy chain (r = 0.87, P less than 0.01).

scholarly journals Soleus fiber force and maximal shortening velocity after non-weight bearing with intermittent activity

1996 ◽  
Vol 80 (3) ◽  
pp. 981-987 ◽  
Author(s):  
J. J. Widrick ◽  
J. J. Bangart ◽  
M. Karhanek ◽  
R. H. Fitts
Keyword(s):  
Isometric Force ◽  
Weight Bearing ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Cross Sectional Area ◽  
Type I ◽  
Sectional Area ◽  
Shortening Velocity ◽  
Adult Rats ◽  
Cross Sectional

This study examined the effectiveness of intermittent weight bearing (IWB) as a countermeasure to non-weight-bearing (NWB)-induced alterations in soleus type I fiber force (in mN), tension (Po; force per fiber cross-sectional area in kN/m-2), and maximal unloaded shortening velocity (Vo, in fiber lengths/s). Adult rats were assigned to one of the following groups: normal weight bearing (WB), 14 days of hindlimb NWB (NWB group), and 14 days of hindlimb NWB with IWB treatments (IWB group). The IWB treatment consisted of four 10-min periods of standing WB each day. Single, chemically permeabilized soleus fiber segments were mounted between a force transducer and position motor and were studied at maximal Ca2+ activation, after which type I fiber myosin heavy-chain composition was confirmed by sodium dodecyl sufate-polyacrylamide gel electrophoresis. NWB resulted in a loss in relative soleus mass (-45%), with type I fibers displaying reductions in diameter (-28%) and peak isometric force (-55%) and an increase in Vo (+33%). In addition, NWB induced a 16% reduction in type I fiber Po, a 41% reduction in type I fiber peak elastic modulus [Eo, defined as (delta force/delta length) x (fiber length/fiber cross-sectional area] and a significant increase in the Po/Eo ratio. In contrast to NWB, IWB reduced the loss of relative soleus mass (by 22%) and attenuated alterations in type I fiber diameter (by 36%), peak force (by 29%), and Vo (by 48%) but had no significant effect on Po, Eo, or Po/Eo. These results indicate that a modest restoration of WB activity during 14 days of NWB is sufficient to attenuate type I fiber atrophy and to partially restore type I peak isometric force and Vo to WB levels. However, the NWB-induced reductions in Po and Eo, which we hypothesize to be due to a decline in the number and stiffness of cross bridges, respectively, are considerably less responsive to this countermeasure treatment.

PURIFICATION OF "INHIBIN" FROM HUMAN OVARIAN FOLLICULAR FLUID

1979 ◽  
Vol 90 (1) ◽  
pp. 157-166 ◽  
Author(s):  
S. Chari ◽  
C. R. N. Hopkinson ◽  
E. Daume ◽  
G. Sturm
Keyword(s):  
Follicular Fluid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Exchange Chromatography ◽  
Male Rats ◽  
Acetone Powder ◽  
Gel Chromatography ◽  
Apparent Homogeneity ◽  
Ovarian Follicular Fluid

ABSTRACT Following the earlier demonstration of inhibin-like activity in human ovarian follicular fluid a method for its purification to apparent homogeneity is described. The fluid was converted to acetone powder and subjected sequentially to ammonium sulphate fractionation, gel chromatography on Sephadex G-200, continuous gradient ion-exchange chromatography on DEAE-cellulose, first with a pH gradient from 8.0 to 4.0 and then with a NaCl gradient to 1 m at pH 5.2. The active fraction from this step was subjected to gel filtration on Sephadex G-100 and finally passed through an Amicon Centriflo membrane CF-25 (cut off point: 25 000 m.w.). The ultrafiltrate was homogeneous by SDS-polyacrylamide gel electrophoresis, had a molecular weight of the order of 23 000 and was capable of suppressing serum gonadotrophin levels in the castrated male rats in as low a dose as 25 μg/rat.

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