An Animal Model of Liuzijue Based on Kinematic Features Exploration: A Pilot Study Conducting in COPD

Liuzijue is an essential nonpharmacological intervention within the comprehensive management strategies for chronic obstructive pulmonary disease (COPD) patients. However, the absence of an animal model for Liuzijue presents methodological limitations in its basic research. This study aimed to apply interventions with kinematic characteristics of Liuzijue to COPD mice, with the objective to explore an animal model of Liuzijue suitable for experimental studies.

Forty-eight C57BL/6 mice randomly assigned into six groups to receive interventions mimicking Liuzijue's kinematic features, namely aerobic exercise, pursed-lip breathing and abdominal breathing. Post-intervention, respiratory function, diaphragmatic contractility, and rectus abdominis thickness were assessed. Histological structures of lung tissue, diaphragm, and rectus abdominis were observed using H&E staining. Expression levels of IL-10, INF-γ, and TNF-α in bronchoalveolar lavage fluid, and p65, CasP3, MuRF1, MyoD1, IGF-1, and Hspa5 in the diaphragm and rectus abdominis were measured.

The modeling process impaired respiratory function and diaphragmatic contractility in mice. All four stimulation forms effectively improved pulmonary and diaphragmatic function in COPD mice. The thickness of the rectus abdominis was increased by three specified exercise forms. Despite minimal lung tissue structural changes, swimming and abdominal stimulation improved the structure of the rectus abdominis in COPD mice and airway inflammation levels were inhibited. Lastly, the four stimulations regulated the balance of myoprotein synthesis and degradation in the diaphragm and rectus abdominis, although the intervention effects of the four stimulations did not escalate with the complexity of the methods.

The exercise stimulation paradigms established by simulating the kinematic characteristics of Liuzijue possess the therapeutic effects of Liuzijue in improving respiratory function, demonstrating first evidence that kinematic-based animal models can bridge traditional Qigong and modern mechanism research. However, the development of an animal model for the application of Liuzijue in basic research still warrants further exploration.