Supraspinatus Muscle Architecture and Physiology in a Rabbit Model of Tenotomy and Repair

2021 ◽  
Author(s):  
Sydnee A. Hyman ◽  
Isabella T. Wu ◽  
Laura S. Vasquez-Bolanos ◽  
Mackenzie B. Norman ◽  
Mary C. Esparza ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Isometric Force ◽  
Rabbit Model ◽  
Muscle Length ◽  
Peak Stress ◽  
Structural Data ◽  
Rotator Cuff Tears ◽  
Time Data ◽  
Maximum Isometric Force ◽  
Over Time

Chronic rotator cuff tears can cause severe functional deficits. Addressing the chronic fatty and fibrotic muscle changes is of high clinical interest; however, the architectural and physiological consequences of chronic tear and repair are poorly characterized. We present a detailed architectural and physiological analysis of chronic tear and repair (both over 8 and 16 weeks) compared to age-matched control rabbit supraspinatus (SSP) muscles. Using female New Zealand White Rabbits (N=30, n=6/group) under 2% isofluorane anesthesia, the SSP was surgically isolated and maximum isometric force measured at 4-6 muscle lengths. Architectural analysis was performed, and maximum isometric stress was computed. Whole muscle length-tension curves were generated using architectural measurements to compare experimental physiology to theoretical predictions. Architectural measures are consistent with persistent radial and longitudinal atrophy over time in tenotomy that fail to recover after repair. Maximum isometric force was significantly decreased after 16 wks tenotomy and not significantly improved after repair. Peak isometric force reported here are greater than prior reports of rabbit SSP force after tenotomy. Peak stress was not significantly different between groups and consistent with prior literature of SSP stress. Muscle strain during contraction was significantly decreased after 8-wks of tenotomy and repair, indicating effects of tear and repair on muscle function. The experimental length-tension data was overlaid with predicted curves for each experimental group (generated from structural data), exposing the altered structure-function relationship for tenotomy and repair over time. Data presented here contribute to understanding the physiological implications of disease and repair in the rotator cuff

The Biomechanical and Histological Processes of Rerouting Biceps to Treat Chronic Irreparable Rotator Cuff Tears in a Rabbit Model

2022 ◽  
pp. 036354652110629
Author(s):  
Junjie Xu ◽  
Yufeng Li ◽  
Xueying Zhang ◽  
Kang Han ◽  
Zipeng Ye ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Failure Load ◽  
Biceps Tendon ◽  
Rabbit Model ◽  
Rotator Cuff Tears ◽  
Bicipital Groove ◽  
Superior Capsular Reconstruction ◽  
Over Time

Background: Recently, the biceps was rerouted into a newly fabricated bicipital groove for in situ superior capsular reconstruction (SCR), resulting in promising time-zero cadaveric and clinical outcomes. However, no studies have determined the in vivo biomechanical and histological processes after the biceps is transposed to a nonanatomic position. Purpose: To explore the in vivo biomechanical and histological processes of the rerouting biceps tendon to treat chronic irreparable rotator cuff tears (IRCTs) in a rabbit model. Study Design: Controlled laboratory study. Methods: A total of 94 skeletally mature male rabbits were used to create a chronic IRCT model in the supraspinatus tendon. Then, the biceps rerouting procedures were performed in rabbits with chronic IRCT. Eighteen rabbits were sacrificed at 1, 3, 6, 9, and 12 weeks postoperatively for biomechanical testing, micro—computed tomography scanning, and histological analysis. The biomechanical and histological changes of intra- and extra-articular portions of the rerouting biceps were evaluated at each time point, with the contralateral native superior capsule (NSC) and the native biceps (NB) as controls, respectively. The morphology and bone formation of the fabricated bicipital grooves were evaluated, with native grooves as controls. Results: The intra-articular rerouting biceps tendon was progressively remodeled over time, displaying denser fibers and more mature collagen than those of the NSC, with gradual improvements in the tendon-to-bone healing interface from 6 to 12 weeks. Consequently, the failure load and stiffness of the intra-articular rerouting biceps portion increased with time and were significantly higher than those of the NSC from 9 weeks. Similarly, the extra-articular portion of the rerouting biceps progressively healed into a new bicipital groove, as demonstrated by a smaller tendon-to-bone interface from 6 to 12 weeks, resulting in greater failure load and stiffness at 9 and 12 weeks than those of the NB attachment. The newly fabricated bicipital groove showed similar morphology to that of the native groove with sufficient trabecular bone formed underneath. Conclusion: The rerouting biceps could progressively remodel and heal into the newly fabricated bicipital groove over time, resulting in greater biomechanical performances in intra- and extra-articular portions than the NSC and the NB attachment. Clinical Relevance: The biceps rerouting technique may be a feasible procedure to perform in situ SCR to treat IRCT in the future clinical practice; however, more clinical evidence is required.

Bridging Repair of Large Rotator Cuff Tears Using a Multilayer Decellularized Tendon Slices Graft in a Rabbit Model

2018 ◽  
Vol 34 (9) ◽  
pp. 2569-2578 ◽  
Author(s):  
Guo-Ming Liu ◽  
Juan Pan ◽  
Yi Zhang ◽  
Liang-Ju Ning ◽  
Jing-Cong Luo ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Rabbit Model ◽  
Rotator Cuff Tears

Freeze-dried chitosan-platelet-rich plasma implants improve supraspinatus tendon attachment in a transosseous rotator cuff repair model in the rabbit

2018 ◽  
Vol 33 (6) ◽  
pp. 792-807 ◽  
Author(s):  
Gabrielle Deprés-Tremblay ◽  
Anik Chevrier ◽  
Martyn Snow ◽  
Scott Rodeo ◽  
Michael D Buschmann
Keyword(s):  
Rotator Cuff ◽  
Rotator Cuff Repair ◽  
Platelet Rich Plasma ◽  
Rabbit Model ◽  
Supraspinatus Tendon ◽  
Rotator Cuff Tears ◽  
Polymorphonuclear Cells ◽  
Post Surgery ◽  
Freeze Dried ◽  
Cuff Repair

Rotator cuff tears result in shoulder pain, stiffness, weakness and loss of motion. After surgical repair, high failure rates have been reported based on objective imaging and it is recognized that current surgical treatments need improvement. The aim of the study was to assess whether implants composed of freeze-dried chitosan (CS) solubilized in autologous platelet-rich plasma (PRP) can improve rotator cuff repair in a rabbit model. Complete tears were created bilaterally in the supraspinatus tendon of New Zealand White rabbits ( n = 4 in a pilot feasibility study followed by n = 13 in a larger efficacy study), which were repaired using transosseous suturing. On the treated side, CS-PRP implants were injected into the transosseous tunnels and the tendon itself, and healing was assessed histologically at time points ranging from one day to two months post-surgery. CS-PRP implants were resident within transosseous tunnels and adhered to tendon surfaces at one day post-surgery and induced recruitment of polymorphonuclear cells from 1 to 14 days. CS-PRP implants improved attachment of the supraspinatus tendon to the humeral head through increased bone remodelling at the greater tuberosity and also inhibited heterotopic ossification of the supraspinatus tendon at two months. In addition, the implants did not induce any detectable deleterious effects. This preliminary study provides the first evidence that CS-PRP implants could be effective in improving rotator cuff tendon attachment in a small animal model.

scholarly journals Enhanced Tendon-to-Bone Healing of Chronic Rotator Cuff Tears by Bone Marrow Aspirate Concentrate in a Rabbit Model

2018 ◽  
Vol 10 (1) ◽  
pp. 99 ◽  
Author(s):  
Xiao Ning Liu ◽  
Cheol-Jung Yang ◽  
Ji Eui Kim ◽  
Zhen Wu Du ◽  
Ming Ren ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Rotator Cuff ◽  
Bone Healing ◽  
Bone Marrow Aspirate ◽  
Rabbit Model ◽  
Rotator Cuff Tears ◽  
Bone Marrow Aspirate Concentrate

A bladder contractility constant

1983 ◽  
Vol 245 (5) ◽  
pp. R673-R677
Author(s):  
J. C. Byrne ◽  
A. Tozeren
Keyword(s):  
Initial Velocity ◽  
Active Component ◽  
Isometric Force ◽  
Muscle Length ◽  
Rate Of Change ◽  
Contractile Element ◽  
Tetanic Contraction ◽  
Muscle Contractility ◽  
Maximum Isometric Force ◽  
The Moment

Muscle contractility can be characterized by two related properties: force and velocity. The initial velocity of a tetanic contraction is inversely related to preload. This was demonstrated experimentally by Hill and quantified in his well-known empiric equation. Subsequent investigators argued that a theoretical maximum contractile element velocity (V max) could be predicted from the rate of change of isometric force. V max has been applied clinically in heart studies, prompting others to use similar methods to evaluate bladder contractility. These attempts have so far been unsuccessful. The present study shows for whole canine bladders that the time to reach maximum isometric force from the moment of onset of active contraction is a constant independent of muscle length, preload, and maximum force. This can be expressed as a frequency constant (omega) whose calculation appears similar to that for V max. In contrast to V max, omega is obtained only from the active component of pressure.

Isotonic relaxation in cardiac muscle

1975 ◽  
Vol 229 (3) ◽  
pp. 646-651 ◽  
Author(s):  
JE Strobeck ◽  
AS Bahler ◽  
EH Sonnenblick
Keyword(s):  
Cardiac Muscle ◽  
Isometric Force ◽  
Muscle Length ◽  
Constant Load ◽  
Papillary Muscles ◽  
Initial Length ◽  
Total Load ◽  
Relaxation Velocity ◽  
Force Velocity ◽  
Maximum Isometric Force

The force-velocity-length determinants of isotonic relaxation were studied in 12 cat papillary muscles. Isotonic relaxation velocity (VL) was found to be a function of total load (preload + afterload), with peak VL increasing to a maximum at loads approximately .3 to .4 Po(L') (Po(L') defined as maximum isometric force developed during a twitch at the experimental length) and falling with increasing loads. Initial muscle length (ML) had no effect on the peak VL with constant load. Increasing the initial length at which isotonic relaxation occurred (LL) decreased peak VL but did not alter the unique length-velocity trajectory at constant load. This unique length-velocity trajectory occurred, despite a wide variation in time during the contraction when peak VL was measured. Increasing Ca++ from 2.5 to 7.5 mM increased peak VL (1.73 +/- .16 to 2.32 +/- .20 ML/s) and shifted the entire length-velocity trajectory toward higher velocities of lengthening. The addition of 10 mM caffeine increased peak VL also (1.67 +/- .18 to 2.54 +/- .20 ML/s) and had a similar effect on the length-velocity trajectory during lengthening as Ca++. Both increased Ca++ and caffeine (10 mM) augmented the maximum VL measured on addition of load.

Preload does not affect relaxation rate in normal, hypoxic, or hypertrophic myocardium

1990 ◽  
Vol 258 (1) ◽  
pp. H191-H197 ◽  
Author(s):  
M. R. Zile ◽  
C. H. Conrad ◽  
W. H. Gaasch ◽  
K. G. Robinson ◽  
O. H. Bing
Keyword(s):  
Relaxation Rate ◽  
Isometric Force ◽  
Muscle Length ◽  
Independent Effect ◽  
Shr Rats ◽  
Spontaneously Hypertensive ◽  
Maximum Isometric Force ◽  
Hypertrophic Myocardium ◽  
Wistar Kyoto ◽  
Tension Curves

To determine whether isolated changes in preload (end-diastolic force) can influence myocardial relaxation rate in normal or abnormal (hypoxic or hypertrophic) hearts, isolated LV papillary muscles from normal Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats were studied using physiologically sequenced contractions. While total (systolic) load and late (lengthening) load were held constant, maximum isometric force decline (peak -dT/dt) and maximum isotonic lengthening rate (peak +dL/dt) were measured at seven levels of preload that varied from 115 to 55% of the resting tension at maximum length-tension curves (Lmax). Muscles from normal rats were studied in the oxygenated state (95% O2-5% CO2) and in the hypoxic state (95% N2-5% CO2). Preload did not effect peak -dT/dt or peak +dL/dt in either oxygenated or hypoxic muscles. During hypoxia, peak -dT/dt and peak +dL/dt were 9.5 +/- 1.0 g.mm-2.s-1 and 0.3 +/- 0.1 muscle length/s, respectively, at a preload of 115% compared with 9.0 +/- 1.2 g.mm-2.s-1 and 0.2 +/- 0.1 at a preload of 55%. In separate experiments, the effect of preload on relaxation rate was studied in WKY and SHR rats. In neither group did preload have an independent effect on relaxation rate. In the SHRs, peak -dT/dt and peak +dL/dt were 24.3 +/- 5.3 g.mm-2.s-1 and 0.7 +/- 0.1 muscle length/s, respectively, at a preload of 115% compared with 24.7 +/- 6.6 and 0.8 +/- 0.1 at a preload of 55%. Thus, in hypoxic and hypertrophic myocardium, as in normal muscle, an acute isolated change in preload did not influence the rate of force decline or muscle lengthening.

scholarly journals EGR1 Induces Tenogenic Differentiation of Tendon Stem Cells and Promotes Rabbit Rotator Cuff Repair

2015 ◽  
Vol 35 (2) ◽  
pp. 699-709 ◽  
Author(s):  
Xu Tao ◽  
Junpeng Liu ◽  
Lei Chen ◽  
You Zhou ◽  
Kanglai Tang
Keyword(s):  
Stem Cells ◽  
Rotator Cuff ◽  
Rotator Cuff Repair ◽  
Rabbit Model ◽  
Tendon Repair ◽  
Rotator Cuff Tears ◽  
Rotator Cuff Tendon ◽  
Tenogenic Differentiation ◽  
Tendon Stem Cells ◽  
Cuff Repair

Background/Aims: The rate of healing failure after surgical repair of chronic rotator cuff tears is considerably high. The aim of this study was to investigate the function of the zinc finger transcription factor early growth response 1 (EGR1) in the differentiation of tendon stem cells (TSCs) and in tendon formation, healing, and tendon tear repair using an animal model of rotator cuff repair. Methods: Tenocyte, adipocyte, osteocyte, and chondrocyte differentiation as well as the expression of related genes were determined in EGR1-overexpressing TSCs (EGR1-TSCs) using tissue-specific staining, immunofluorescence staining, quantitative PCR, and western blotting. A rabbit rotator cuff repair model was established, and TSCs and EGR1-TSCs in a fibrin glue carrier were applied onto repair sites. The rabbits were sacrificed 8 weeks after repair operation, and tissues were histologically evaluated and tenocyte-related gene expression was determined. Results: EGR1 induced tenogenic differentiation of TSCs and inhibited non-tenocyte differentiation of TSCs. Furthermore, EGR1 promoted tendon repair in a rabbit model of rotator cuff injury. The BMP12/Smad1/5/8 signaling pathway was involved in EGR1-induced tenogenic differentiation and rotator cuff tendon repair. Conclusion: EGR1 plays a key role in tendon formation, healing, and repair through BMP12/Smad1/5/8 pathway. EGR1-TSCs is a promising treatment for rotator cuff tendon repair surgeries.

scholarly journals Biceps tendon properties worsen initially but improve over time following rotator cuff tears in a rat model

2011 ◽  
Vol 29 (6) ◽  
pp. 874-879 ◽  
Author(s):  
Cathryn D. Peltz ◽  
Jason E. Hsu ◽  
Miltiadis H. Zgonis ◽  
Nicholas A. Trasolini ◽  
David L. Glaser ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Rat Model ◽  
Biceps Tendon ◽  
Rotator Cuff Tears ◽  
Tendon Properties ◽  
Over Time
Sign in / Sign up

Export Citation Format

Share Document