measuring mechanical properties of quadriceps femoris contraction force in rabbits

Istituzione del modello KOA nei conigli utilizzando il metodo Videman modificato

Knee osteoarthritis (KOA) is the most frequent form of osteoarthritis, often recognized as a whole-joint disease characterized by articular cartilage degeneration, which manifests clinically as pain, swelling, and limited movement of the affected joints1. According to recent epidemiological statistics, KOA is reported to have affected 654.1 million individuals globally who were 40 years of age or older by 2020. The prevalence and incidence of KOA rise with age, are the highest in middle-aged and older adults, and affect more women than men2. The prevalence of KOA is likely to increase due to the aging population and obesity epidemic worldwide, posing a growing threat to global public health. Age, sex, obesity, trauma, and other complicated risk factors associated with KOA all directly impact knee instability, making a biomechanical imbalance in knee joints one of the primary causes of KOA3.
Under normal physiological conditions, the knee joint is in a state of mechanical balance, ensuring that the mechanical loads in the joint are evenly distributed on the cartilage. Any mechanical imbalance in the knee joint can lead to abnormal stress in cartilage, resulting in cartilage degeneration and the onset of KOA4. The muscle-tendon system is the main dynamic system that maintains the mechanical balance of the knee joint. The coordinated movement of the extensor and flexor muscle-tendon system can evenly distribute the load generated by the movement on the cartilage surface, avoiding the metabolic imbalance of local cartilage stresses beyond its physiological load that results in cartilage loss5. Decreased muscle strength is the main cause of intramuscular movement disorder and cartilage damage, which may occur before symptomatic KOA. 
KOA can also induce arthrogenous muscle inhibition (AMI), manifesting as muscle weakness and decreased muscle strength around the knee6. Among these muscles, the quadriceps femoris group functions as the only knee extensor, an important structure in maintaining knee joint stability. Studies have shown that a decrease in quadriceps cross-sectional area and muscle strength is significantly and positively correlated with KOA progression7. The decline in quadriceps strength affects the gait pattern, knee stability, movement patterns, and many other functions. Moreover, the decline in muscle strength impairs tendon function, manifested as a decrease in tendon stiffness, elastic modulus, and other biomechanical properties8. In long-term strain repair, changes such as adhesion and contracture may occur in the muscles and tendons of the knee joint, damaging their mechanical properties, causing joint instability, and ultimately forming a vicious cycle of pathological changes of KOA. It is, therefore, crucial for KOA treatment to improve the mechanical properties of the muscle-tendon system and restore the joint mechanical balance.
Among the causes of KOA, biomechanical imbalance is the main inducing factor for knee pain, dysfunction, inflammatory lesions, and cartilage degeneration9. Therefore, the key to treating KOA is to restore the biomechanical balance of the knee joint. Acupotomology believes that the etiology and pathogenesis of KOA are "mechanical imbalance." When the mechanical characteristics of the soft tissues around the knee change abnormally, the knee joint loses its mechanical balance, and the abnormal mechanical stress environment of the joint accelerates degeneration, causing inflammatory stimulation to further aggravate the soft tissue adhesions, contractures, and further decline in joint stability. This vicious cycle eventually develops into KOA. By loosening soft tissue adhesions and contractures, as well as reducing stress concentration in the muscles and tendons, acupotomy in conjunction with the theory of "Modulating Muscles and Tendons to Treat Bone Disorders" improves the soft tissue mechanics and "modulates muscles and tendons," which balances the mechanical stress of the joint, effectively alleviating cartilage degeneration and "treating bone disorders"10. In terms of animal model selection, based on the purpose of this study, we prepared the KOA model by the modified Videman method of left hindlimb extension immobilization.
This paper details the establishment of the KOA model using the modified Videman method of left hind limb extension immobilization and the method of operation and precautions of acupotomy. We demonstrate the effectiveness of acupotomy by testing the mechanical properties of quadriceps femoris and tendon and detecting changes in articular cartilage stress and morphology.

Autore in primo piano: Indagine sul meccanismo d'azione dell'acupotomia nel trattamento dell'osteoartrosi del ginocchio

Applicazione dell'agopotomia in un modello di osteoartrite del ginocchio nel coniglio

Our research scope is the study of the mechanism of action of acupotomy in the treatment of new osteoarthritis. The question we want to answer, the how acupotomy regulates the mechanical properties of the soft tissues around the knee to protect the cartilage. At present, micro CT, nuclear magnetic resonance, phenetole elemental analysis, and bio mechanical detection techniques can be used to promote research in this field.We found that acupotomy improved the mechanical properties of soft tissue by removing the excisions and pathological contractors around the knee, thereby playing a role in protecting cartilage. To a certain extent, this protocol explains the mechanism and reveals the scientific connotation of acupotomy in the treatment of KOA and fills the gap in the basic research of acupotomy tendon and bone treatment method. In the future, our laboratory will focus on the specific mechanism or action of the acupotomy tendon and bone control method on cartilage protection.

Watch this Scientific Journal Video about Measuring Mechanical Properties of Quadriceps Femoris Contraction Force in Rabbits at JoVE.com

Misurazione delle proprietà meccaniche della forza di contrazione del quadricipite femorale nei conigli

Per iniziare, tagliare la pelle di un coniglio anestetizzato sotto la rotula, seguendo la lunghezza dell'arto verso l'alto fino alla base della coscia, quindi continuare verso l'alto per tre o quattro centimetri. Staccare con cura la pelle e la fascia, esponendo il muscolo quadricipite. Tagliare il legamento rotuleo e separare con cura i quadricipiti dalla giunzione iliaca, mantenendo i quadricipiti in connessione con l'ilicio.Ora legare le suture chirurgiche alla giunzione tendinea tra la rotula e il muscolo quadricipite. Allungare il muscolo per tutta la sua lunghezza nel suo stato naturale e collegarlo al trasduttore di tensione, allineando la linea di legatura sul muscolo con quella sul trasduttore. Fissare il trasduttore di tensione alla staffa.Collegare la linea di acquisizione del segnale sul trasduttore al processore del sistema di acquisizione del segnale biologico. Inserire gli elettrodi parallelamente all'addome del quadricipite, evitando il contatto tra gli elettrodi. Quindi, premere il pulsante dell'oscilloscopio.Regolare la posizione del trasduttore di forza sulla staffa per mantenere la linea di base a zero. In questa fase, impostare i parametri di stimolazione dello stimolatore con un singolo stimolo, un'ampiezza d'onda di cinque millisecondi e un ritardo di 10 millisecondi. Impostare il valore iniziale dell'ampiezza dello stimolo a zero volt e impostare l'ampiezza automatica in modo che aumenti di 0,1 volt ogni volta, per aumentare gradualmente l'intensità dello stimolo.Quindi iniziare la stimolazione osservando i cambiamenti nella curva delle contrazioni muscolari e nell'ampiezza della contrazione, fino a determinare l'ampiezza massima della contrazione del segnale del quadricipite. Successivamente, usa uno stimolo a grappolo e imposta l'ampiezza dello stimolo, provocando una singola contrazione massima come linea di base per stimolare continuamente il muscolo. Impostare il valore iniziale della frequenza di stimolazione su 10 hertz e impostare la frequenza automatica in modo che aumenti di un hertz ogni volta per aumentare gradualmente la frequenza di stimolo.Infine, iniziare la stimolazione osservando le variazioni della curva di contrazione muscolare fino a determinare l'ampiezza massima di contrazione tetanica del quadricipite. Il modulo di Young, l'ampiezza della contrazione singola e l'ampiezza della contrazione tetanica del quadricipite femorale sono stati significativamente ridotti nel gruppo osteoartrite del ginocchio rispetto al gruppo di controllo e agopotomia.

measuring-mechanical-properties-quadriceps-femoris-contraction-force

Research

JoVE Journal

Medicine

Measuring Mechanical Properties of Quadriceps Femoris Contraction Force in Rabbits

53 Views.  Beijing University of Chinese Medicine. To begin, cut the skin of an anesthetized rabbit below the patella, following the length of the limb upwards to the thigh base, then continue upwards for three to four centimeters. Carefully peel off the skin and fascia, exposing the quadriceps muscle. Cut the patellar ligament and carefully separate the quadriceps from the iliac junction, while maintaining the quadriceps in connection with the ilicium.Now ligate the surgical sutures at the tendon junction between the patella and quadr...