Administration of Particulate Oxygen Generators Improves Skeletal Muscle Contractile Function Following Ischemia-Reperfusion Injury in the Rat Hind Limb

Author(s):  
Sarah E. Dyer ◽  
J. David Remer ◽  
Kelsey E. Hannifin ◽  
Aishwarya Hombal ◽  
Joseph C. Wenke ◽  
...  

Extended tourniquet application, often associated with battlefield extremity trauma, can lead to severe ischemia-reperfusion (I/R) injury in skeletal muscle. Particulate oxygen generators (POGs) can be directly injected into tissue to supply oxygen to attenuate the effects of I/R injury in muscle. The goal of this study was to investigate the efficacy of a sodium percarbonate (SPO)-based POG formulation in reducing ischemic damage in a rat hind limb during tourniquet application. Male Lewis rats were anesthetized and underwent tourniquet application for 3 hours, at a pressure of 300 mmHg. Shortly after tourniquet inflation animals received intramuscular injections of either 0.2 mg/mL SPO with catalase (n=6) or 2.0 mg/mL SPO with catalase (n=6) directly into the tibialis anterior (TA) muscle. An additional Tourniquet-Only group (n=12) received no intervention. Functional recovery was monitored using in vivo contractile testing of the hind limb at 1-, 2-, and 4-weeks post-injury. By the 4 week time point, the Low Dose POGs group continued to show improved functional recovery (85% of baseline) compared to the Tourniquet-Only (48%) and High Dose POG (56%) groups. In short, the Low Dose POGs formulation appeared, at least in part, to mitigate the impact of ischemic tissue injury, thus improving contractile function following tourniquet application. Functional improvement correlated with maintenance of larger muscle fiber cross sectional area, and the presence of fewer fibers containing centrally located nuclei. As such, POGs represent a potentially attractive therapeutic solution for addressing I/R injuries associated with extremity trauma.

1998 ◽  
Vol 274 (3) ◽  
pp. R822-R829 ◽  
Author(s):  
Long-En Chen ◽  
Anthony V. Seaber ◽  
Rima M. Nasser ◽  
Jonathan S. Stamler ◽  
James R. Urbaniak

The ultimate goal of replantation and microsurgical reconstructive operations is to regain or improve impaired function of the tissue. However, the data related to the influence of NO on tissue function are limited. This study evaluated the effects of the NO donor S-nitroso- N-acetylcysteine (SNAC) on contractile function of skeletal muscle during reperfusion. Forty-nine rats were divided into six groups. The extensor digitorum longus (EDL) muscles in groups I and II were not subjected to ischemia-reperfusion but were treated with a low (100 nmol/min) or high (1 μmol/min) dose of SNAC. In groups III- V, the EDL underwent 3 h of ischemia and 3 h of reperfusion and was also treated with low (100 nmol/min) or high doses (1 or 5 μmol/min) of SNAC. Group VI was a phosphate-buffered saline (PBS)-treated control group. Twenty additional animals were used to document systemic effects of SNAC and PBS only. SNAC or PBS was infused for 6.5 h, beginning 30 min before ischemia and continuing throughout the duration of reperfusion. Contractile testing compared the maximal twitch force, isometric tetanic contractile forces, fatigue, and fatigue half time of the experimental EDL and the contralateral nontreated EDL. The findings indicate that 1) SNAC does not influence contractile function of EDL muscle not subjected to ischemia-reperfusion, 2) SNAC significantly protects the contractile function of ischemic skeletal muscle against reperfusion injury in the early reperfusion period, and 3) the protective role of SNAC is critically dosage dependent; protection is lost at higher doses. The conclusion from this study is that supplementation with exogenous NO exerts a protective effect on the tissue against reperfusion injury.


2014 ◽  
Vol 92 (4) ◽  
pp. 338-349 ◽  
Author(s):  
Kiranj K. Chaudagar ◽  
Anita A. Mehta

Atorvastatin, a lipid lowering agent, possesses various pleiotropic vasculoprotective effects, but its role in coronary angiogenesis is still controversial. Our objective was to study the effects of atorvastatin on the angiogenic responsiveness of coronary endothelial cells (cEC) from normal and diabetic rats. Male Wistar rats were distributed among 9 groups; (i) normal rats, (ii) 30 day diabetic rats, (iii) 60 day diabetic rats, (iv) normal rats administered a low dose of atorvastatin (1 mg/kg body mass, per oral (p.o.), for 15 days); (v) 30 day diabetic rats administered a low dose of atorvastatin; (vi) 60 day diabetic rats administered a low dose of atorvastatin; (vii) normal rats administered a high dose of atorvastatin (5 mg/kg, p.o., for 15 days); (viii) 30 day diabetic rats administered a high dose of atorvastatin; (ix) 60 day diabetic rats administered a high dose of atorvastatin. Each group was further divided into 2 subgroups, (i) sham ischemia–reperfusion and (ii) rats hearts that underwent ischemia–reperfusion. Angiogenic responsiveness the and nitric oxide (NO) releasing properties of the subgroups of cECs were studied using a chorioallantoic membrane assay and the Griess method, respectively. Atorvastatin treatment significantly increased VEGF-induced angiogenic responsiveness and the NO-releasing properties of cECs from all of the subgroups, compared with their respective non-treated subgroups except for the late-phase diabetic rat hearts that underwent ischemia–reperfusion, and the high dose of atorvastatin treatment groups. These effects of atorvastatin were significantly inhibited by pretreatment of cECs with l-NAME, wortmannin, and chelerythrine. Thus, treatment with a low dose of atorvastatin improves the angiogenic responsiveness of the cECs from normal and diabetic rats, in the presence of VEGF, via activation of eNOS–NO release.


1996 ◽  
Vol 80 (1) ◽  
pp. 332-340 ◽  
Author(s):  
C. P. Ingalls ◽  
G. L. Warren ◽  
D. A. Lowe ◽  
D. B. Boorstein ◽  
R. B. Armstrong

The purpose of this study was to evaluate the effects of four anesthetic regimens on in vivo contractile function of mouse ankle dorsiflexor muscles. The torque-frequency and torque-velocity relationships were determined for the following anesthetics: fentanyl-droperidol and diazepam (F-d/d); ketamine and xylazine (K/x); pentobarbital sodium (Ps); and methoxyflurane (Mf). Mf, Ps, and F-d/d regimens resulted in comparable contractile responses at low doses, whereas K/x produced a relative depression in isometric contractile function as shown by a decrease in the torque-time integral at the 300-Hz stimulation frequency (-13.9%; P < 0.05). Moreover, K/x caused a shift to the left in the torque-frequency curve as indicated by increases in torque-time integrals at 25 and 50 Hz. Both Ps and F-d/d regimens exhibited dose-dependent effects during the isovelocity contractions. Ps significantly reduced work (-28.7%) and average power (-28.9%) at 800 degrees/s at the high dose. In contrast, F-d/d anesthesia resulted in increases in peak torque (16-20%) and work (15-18%) output at all eccentric contraction velocities at the high dose, whereas average power was increased only at -800 (17%) and -1,000 degrees/s (17%). In conclusion, commonly used anesthetic regimens can affect the contractile response in vivo; K/x and Ps yield smaller torque outputs, whereas Mf and F-d/d consistently produce larger contractile responses. Mf and F-d/d are recommended for use in studying skeletal muscle function in mice in vivo.


2008 ◽  
Vol 48 (3) ◽  
pp. 701-708 ◽  
Author(s):  
Jeanwan Kang ◽  
Hassan Albadawi ◽  
Virendra I. Patel ◽  
Thomas A. Abbruzzese ◽  
Jin-Hyung Yoo ◽  
...  

2019 ◽  
Vol 301 (1) ◽  
pp. 69-73 ◽  
Author(s):  
Mauricio La Rosa ◽  
Chasey Omere ◽  
Tiffany Redfern ◽  
Mahmoud Abdelwahab ◽  
Nicholas Spencer ◽  
...  

2005 ◽  
Vol 288 (1) ◽  
pp. H221-H226 ◽  
Author(s):  
Meijing Wang ◽  
Ben M. Tsai ◽  
Ajay Kher ◽  
Lauren B. Baker ◽  
G. Mathenge Wairiuko ◽  
...  

Myocardial ischemia is the leading cause of death in both men and women; however, very little information exists regarding the effect of testosterone on the response of myocardium to acute ischemic injury. We hypothesized that testosterone may exert deleterious effects on myocardial inflammatory cytokine production, p38 MAPK activation, apoptotic signaling, and myocardial functional recovery after acute ischemia-reperfusion (I/R). To study this, isolated, perfused rat hearts (Langendorff) from adult males, castrated males, and males treated with a testosterone receptor blocker (flutamide) were subjected to 25 min of ischemia followed by 40 min of reperfusion. Myocardial contractile function (left ventricular developed pressure, left ventricular end-diastolic pressure, positive and negative first derivative of pressure) was continuously recorded. After reperfusion, hearts were analyzed for expression of tissue TNF-α, IL-1β, and IL-6 (ELISA) and activation of p38 MAPK, caspase-1, caspase-3, caspase-11, and Bcl-2 (Western blot). All indices of postischemic myocardial functional recovery were significantly higher in castrated males or flutamide-treated males compared with untreated males. After I/R, castrated male and flutamide-treated male hearts had decreased TNF-α, IL-1β, and IL-6; decreased activated p38 MAPK; decreased caspase-1, caspase-3, and caspase-11; and increased Bcl-2 expression compared with untreated males. These results show that blocking the testosterone receptor (flutamide) or depleting testosterone (castration) in normal males improves myocardial function after I/R. These effects may be attributed to the proinflammatory and/or the proapoptotic properties of endogenous testosterone. Further understanding may allow therapeutic manipulation of sex hormone signaling mechanisms in the treatment of acute I/R.


Author(s):  
Sandra Loerakker ◽  
Emmy Manders ◽  
Gustav J. Strijkers ◽  
Frank P. T. Baaijens ◽  
Dan L. Bader ◽  
...  

Sustained mechanical loading of soft tissues covering bony prominences, as experienced by bedridden and wheelchair-bound individuals, may cause skeletal muscle damage. This can result in a condition termed pressure-related deep tissue injury (DTI), a severe kind of pressure ulcer that initiates in deep tissue layers, and progresses towards the skin. Damage pathways leading to DTI can involve ischemia, ischemia/reperfusion injury, impaired lymphatic drainage, and sustained tissue deformation. Recently, we have provided evidence that in a controlled animal model, deformation is the main trigger for damage within a 2h loading period [1,2]. However, ischemia and reperfusion may play a more important role in the damage process during prolonged loading periods.


2000 ◽  
Vol 279 (6) ◽  
pp. H2975-H2985 ◽  
Author(s):  
Kun Don Yi ◽  
H. Fred Downey ◽  
Xiaoming Bian ◽  
Min Fu ◽  
Robert T. Mallet

Although the β1-adrenergic agent dobutamine is used clinically to provide inotropic support to the failing myocardium, it could jeopardize the myocardium by depleting energy reserves. This investigation delineated the contractile and energetic effects of low versus high dobutamine doses in the hypoperfused right ventricular (RV) myocardium. The right coronary artery (RCA) of anesthetized dogs was cannulated for controlled perfusion with arterial blood, and regional RV contractile function was measured. RCA perfusion pressure was lowered from 100 mmHg baseline to 40 mmHg, and flow fell by 54%. At 15-min hypoperfusion, dobutamine was infused into the RCA at either 0.01 (low-dose dobutamine) or 0.06 μg · kg−1· min−1(high-dose dobutamine) for 15 min. Regional power (systolic segment shortening × isometric developed force × heart rate) stabilized at 63% of baseline during hypoperfusion. Low-dose dobutamine restored power to baseline but did not increase RV myocardial O2consumption (MV˙o2) and thus increased myocardial O2utilization efficiency (O2UE:power/MV˙o2). At 5 min, high-dose dobutamine enhancement of power was similar to that of low-dose dobutamine, but by 15 min, power and O2UE fell to untreated levels. Remarkably, low-dose dobutamine tripled cytosolic phosphorylation potential; in contrast, high-dose dobutamine lowered phosphorylation potential to 45% of the untreated value. Analyses of glucose uptake and glycolytic intermediates revealed sustained enhancement of glycolysis by low-dose dobutamine, but glycolysis became limited at glyceraldehyde 3-phosphate dehydrogenase during high-dose dobutamine treatment. In summary, low-dose dobutamine improved mechanical performance and efficiency of the hypoperfused RV myocardium while increasing myocardial energy reserves, but high-dose dobutamine failed to sustain improved function and depleted energy reserves. Dobutamine is capable of improving both contractile function and cellular energetics in the hypoperfused RV myocardium, but dosage should be carefully selected.


1986 ◽  
Vol 251 (2) ◽  
pp. H364-H373 ◽  
Author(s):  
R. D. Goldfarb ◽  
L. M. Nightingale ◽  
P. Kish ◽  
P. B. Weber ◽  
D. J. Loegering

Our previous studies suggested that after a median lethal dose (LD50) of endotoxin, cardiac contractility was depressed in nonsurviving dogs. The canine cardiovascular system is unlike humans in that dogs have a hepatic vein sphincter that is susceptible to adrenergic stimulation capable of raising hepatic and splanchnic venous pressures. We retested the hypothesis that lethality after endotoxin administration is associated with cardiac contractile depression in pigs, because the hepatic circulation in this species is similar to that of humans. We compared cardiac mechanical function of pigs administered a high dose (250 micrograms/kg) or a low dose (100 micrograms/kg) endotoxin by use of the slope of the end-systolic pressure-diameter relationship (ESPDR) as well as other measurements of cardiac performance. In all the pigs administered a high dose, ESPDR demonstrated a marked, time-dependent depression, whereas we observed no significant ESPDR changes after low endotoxin doses. The other cardiodynamic variables were uninterpretable, due to the significant changes in heart rate, end-diastolic diameter (preload), and aortic diastolic pressure (afterload). Plasma myocardial depressant factor activity accumulated in all endotoxin-administered animals, tending to be greater in the high-dose group. In this group, both subendocardial blood flow and global function were depressed, whereas pigs administered the low dose of endotoxin demonstrated slight, but nonsignificant, increases in flow and function. These observations indicate that myocardial contractile depression is associated with a lethal outcome to high doses of endotoxin. One possible mechanism for this loss of contractile function may be a relative hypoperfusion of the subendocardium.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
J Chen ◽  
Y N Song ◽  
Z Y Huang

Abstract Background Poor cell homing limits efficacy of cardiac cellular therapy. The cysteine–arginine–glutamic acid–lysine–alanine (CREKA) homing peptide binds with high specificity to fibrin which is involved in repair of tissue injury. Purpose We assessed if CREKA-modified stem cells had enhanced fibrin-mediated homing ability resulting in better functional recovery and structural preservation in a rat myocardial injury model. Methods CREKA-modified mesenchymal stem cells (CREKA-MSCs) were obtained via membrane fusion with CREKA-modified liposomes. The fibrin targeting ability of CREKA-MSCs was examined both in vitro and in vivo. Results Under both static and flow conditions in vitro, CREKA significantly enhanced MSCs binding ability to fibrin clots. CREKA-MSCs showed much more higher accumulation than unmodified MSCs in injured rat myocardium, colocalizing with fibrin and resulting in better cardiac function. Stem cell-CREKA-fibrin targeting system Conclusions Modification of MSCs with the homing peptide CREKA favored their migration and retention in the infarcted area, resulting in better structural preservation and functional recovery. Fibrin is therefore a novel target for enhancing homing of transplanted cells to injured myocardium and the fibrin-targeting delivery system represents a generalizable platform technology for regenerative medicine.


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