Knee osteoarthritis (KOA) is a degenerative disease mainly manifested in joint pain. Fibrosis, cracking, ulceration, and loss of articular cartilage are the main causes of this disease1. KOA has a high prevalence and may result in a profound impact on the daily life of patients, causing disability in severe cases. Among people aged 45-84 years, the prevalence of KOA increases with age, and the prevalence among people aged 85 years and above is 15%, with a predominance in women2,3. In addition, KOA might bring a serious economic burden on both the individual and the society. A survey showed that direct health care costs on KOA per capita reached up to $8,858 ± $5,120 per year4. With the aging of society, KOA has become a worldwide health problem and a major social issue, as well as a topical issue for scientific research.
Evidence-based studies have shown the effectiveness of Tuina manipulation in treating KOA5. Tuina manipulation could relieve pain and improve dysfunction in KOA patients, the mechanism of which is related to anti-inflammatory effects6,7. Scholars found that Tuina manipulation effectively inhibited the expression of inflammatory factors interleukin (IL)-β and 5-hydroxytryptamine and slowed down the degeneration of articular cartilage in a rabbit KOA model8. It suggested that Tuina could promote blood circulation and metabolism at the lesion site, which helped clear inflammatory factors such as IL-1, IL-6 and tumor necrosis factor (TNF)-α, thereby alleviating the clinical symptoms of KOA9. In addition, the passive movement of the joint through Tuina manipulation can promote the penetration and diffusion of synovial fluid into the articular cartilage and improves tissue nutrient metabolism10. Other studies suggested that Tuina manipulation can effectively improve the biomechanical indexes in KOA patients11. Manipulations applied on soft tissues can improve stress distribution over limbs and enhance balance function12,13. At the same time, with some joint adjustment manipulations, the alignment of the lower limbs can also be adjusted to correct abnormal gaits14,15.
The mechanism of action of Tuina manipulation in treating KOA remains to be explored, and therefore, an experimental study is necessary. The key to the application of Tuina in experimental animals is the standardization of modeling, animal fixation and intervention methods16. The modeling method determines whether the experimental animal can exhibit the characteristics of the disease. Meanwhile, appropriate fixation methods can facilitate the intervention of the Tuina manipulation and better reflect the effect of Tuina. The standardization of intervention methods is the most difficult part of Tuina manipulation. In 2010, the basic system of Chinese acupuncture standards mentioned the acupuncture point standards for experimental animals, providing the possibility for acupuncture and Tuina operations in animal experiments17. However, there are still difficulties in standardizing Tuina manipulation. There are multiple types of Tuina manipulation18. The choice of the specific manipulation mainly depends on the disease to be treated and the therapeutic theories the performer prefers. In the study of Tuina for KOA, more attention has been paid to the point-pressing manipulation (pressing the specific acupoints with the thumb or elbow), Yizhichan pushing manipulation (a pushing manipulation by wiggling the thumb), and press and kneading manipulation (which refers to pressing and kneading the specific area of the body surface by finger or palm)19. Press and kneading manipulation is one of the most widely used Tuina manipulations, which combines pressing and kneading to move the subcutaneous tissue20. Press and kneading manipulation applied on acupoints can promote blood circulation and relieve pain and represents the therapeutic effect of Tuina on KOA19.
In this protocol, the operation of press and kneading manipulation on KOA rats will be described in detail, including selected acupoints, intensity and frequency of the manipulation and the body position of the rat, so as to provide a reference for future research.