This work was supported by the National Natural Science Foundation of China (No.82074523,82104996).

All animal experiments were reviewed and approved by the Animal Ethics Committee of Beijing University of Chinese Medicine (No. BUCM-4-2022010101-1097). In this protocol, 24 6-week-old male New Zealand rabbits were housed under a specific condition, namely, 20-25 &#176;C, 50-60% humidity, and a 12 h light/12 h dark circadian cycle, with free access to a regular chow diet. The rabbits were anesthetized and sacrificed by combining deep anesthesia and air embolization. Pain is one of the typical pathological features of KOA...

Establishment of the KOA Model in Rabbits Using the Modified Videman Method

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An appropriate animal model is one of the key factors to achieve experimental objectives and clarify a specific scientific question. This study was based on the theories of &#34;Zongjin controlling bones and lubricating joints&#34; and &#34;mechanical imbalance&#34; in acupotomology, aiming to explain the scientific connotation behind the treatment of KOA by &#34;modulating muscles and tendons to treat bone disorders&#34; in acupotomy therapy. In other words, acupotomy improves the abnormal mechanical environment of the ...

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.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Acupotomy</td>
			<td>Beijing Zhuoyue Huayou Medical Devices Co., Ltd.</td>
			<td></td>
			<td>0.4 x 40 mm</td>
		</tr>
		<tr>
			<td>Connect Cast Orthopedic Casting Tape</td>
			<td>Suzhou Connect Medical Technology Co.,Ltd.</td>
			<td>KCP06</td>
			<td>15.0 cm x 360 cm</td>
		</tr>
		<tr>
			<td>Double-sided Foam Tape</td>
			<td>Deli Group Co.,Ltd.</td>
			<td>NO.30416</td>
			<td>36 mm x 5 yard x 2.5 mm</td>
		</tr>
		<tr>
			<td>Environmental Dewaxing Solution</td>
			<td>Wuhan Servicebio Technology Co.,Ltd.</td>
			<td>G1128</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol absolute</td>
			<td>Beijing Hengkangda Medicine Co., Ltd.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Fast Green solution</td>
			<td>Wuhan Servicebio Technology Co.,Ltd.</td>
			<td>G1031</td>
			<td></td>
		</tr>
		<tr>
			<td>Fast grenn FCF</td>
			<td>Sigma,America</td>
			<td>2353-45-9</td>
			<td></td>
		</tr>
		<tr>
			<td>Fatigue testing machine</td>
			<td>BOSE, America</td>
			<td></td>
			<td>Bose Electro Force 3300</td>
		</tr>
		<tr>
			<td>Four-channel physiological recorder</td>
			<td>Chengdu Instrumeny Frctory</td>
			<td></td>
			<td>RM-6420</td>
		</tr>
		<tr>
			<td>FPD-305E</td>
			<td>Fuji, Japan</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>FPD-306E</td>
			<td>Fuji, Japan</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hematoxylin solution</td>
			<td>Wuhan Servicebio Technology Co.,Ltd.</td>
			<td>G1005</td>
			<td></td>
		</tr>
		<tr>
			<td>Medical iodophor disinfectant</td>
			<td>Shan Dong Lircon Medical Technology Co., Ltd.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Medical Tape</td>
			<td>Shandong Rongjian Sanitary Products Co., Ltd.</td>
			<td>200402</td>
			<td>1.5 x 500 cm</td>
		</tr>
		<tr>
			<td>Muscle tension transducer&#160;</td>
			<td>Chengdu Instrumeny Frctory</td>
			<td></td>
			<td>JH-2204005, 50 g</td>
		</tr>
		<tr>
			<td>Prescale</td>
			<td>Fuji, Japan</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Real-time SWE ultrasound diagnostic instrument</td>
			<td>SuperSonic Imagine SA,France</td>
			<td></td>
			<td>SuperSonic Imagine AixPlorer</td>
		</tr>
		<tr>
			<td>Rhamsan gum</td>
			<td>Wuhan Servicebio Technology Co.,Ltd.</td>
			<td>WG10004160</td>
			<td></td>
		</tr>
		<tr>
			<td>Safranine O</td>
			<td>Sigma,America</td>
			<td>477-73-6</td>
			<td></td>
		</tr>
		<tr>
			<td>Safranine O solution</td>
			<td>Wuhan Servicebio Technology Co.,Ltd.</td>
			<td>G1015</td>
			<td></td>
		</tr>
		<tr>
			<td>Statistical Package for the Social Sciences (SPSS)</td>
			<td>IBM, America</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

application of acupotomy in a knee osteoarthritis model in rabbit

Knee osteoarthritis (KOA) is one of the most frequently encountered diseases in the orthopedic department, which seriously reduces the quality of life of people with KOA. Among several pathogenic factors, the biomechanical imbalance of the knee joint is one of the main causes of KOA. Acupotomology believes that restoring the mechanical balance of the knee joint is the key to treating KOA. Clinical studies have shown that acupotomy can effectively reduce pain and improve knee mobility by reducing adhesion, contracture of soft tissues, and stress concentration points in muscles and tendons around the knee joint. 
In this protocol, we used the modified Videman method to establish a KOA model by immobilizing the left hindlimb in a straight position. We have outlined the method of operation and the precautions related to acupotomy in detail and evaluated the efficacy of acupotomy in conjunction with the theory of "Modulating Muscles and Tendons to Treat Bone Disorders" through the detection of the mechanical properties of quadriceps femoris and tendon, as well as cartilage mechanics and morphology. The results show that acupotomy has a protective effect on cartilage by adjusting the mechanical properties of the soft tissues around the knee joint, improving the cartilage stress environment, and delaying cartilage degeneration.

Author Spotlight: Investigating the Mechanism of Action of Acupotomy in Treating Knee Osteoarthritis

Application of Acupotomy in a Knee Osteoarthritis Model in Rabbit

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.

Experimental results of mechanical properties of quadriceps femoris and tendon 
To evaluate the effect of acupotomology on the mechanical properties of quadriceps femoris in rabbits with KOA, we used real-time shear wave elastic ultrasound imaging and a muscle tension transducer, respectively. Compared with the control group, Young&#39;s modulus of the quadriceps femoris in the KOA group was decreased (P &#60; 0.05). Compared with the KOA group, Young&#39;s modulus of the acupotomy group wa...

Watch this Scientific Journal Video about Author Spotlight: Investigating the Mechanism of Action of Acupotomy in Treating Knee Osteoarthritis at JoVE.com

In this protocol, a knee osteoarthritis model was prepared using the modified Videman method, and the operation procedures and precautions of acupotomy are detailed. The effectiveness of acupotomy has been demonstrated by testing the mechanical properties of quadriceps femoris and tendon and the mechanical and morphological properties of cartilage.

Knee osteoarthritis (KOA) is one of the most frequently encountered diseases in the orthopedic department, which seriously reduces the quality of life of ...

application-of-acupotomy-in-a-knee-osteoarthritis-model-in-rabbit