Tuina Inhibits Chondrocyte Apoptosis by Regulating the FAK/PI3K/Akt Pathway in Rabbits with IVDD.

BACKGROUND: Intervertebral disc degeneration (IVDD), a key contributor to degenerative spinal diseases such as cervical spondylosis, significantly influences the quality of life of patients. Tuina, historically employed in the clinical management of cervical spondylosis, has demonstrated positive therapeutic outcomes; however, the mechanism of Tuina remains unclear. OBJECTIVE: This study examined the efficacy of Tuina in correcting the imbalanced structure of the cervical spine and its impact on apoptotic chondrocytes within the cervical disc. The underlying mechanisms were explored using a rabbit model of IVDD induced by dynamic and static imbalances. METHODS: The IVDD rabbit model was established by restraining the head in a downward position for 12 weeks (Model group). In the Tuina1 group, treatment was performed on the posterior cervical trapezius muscle daily for 2 weeks, whereas in the Tuina2 group, treatment was performed on both the posterior cervical trapezius and anterior sternocleidomastoid muscles daily for 2 weeks. After treatment, X-ray, micro-computed tomography (CT), histological staining, qRT-PCR, and western blotting were used to evaluate the mechanism by which Tuina inhibits chondrocyte apoptosis. RESULTS: The results demonstrated that Tuina treatment inhibited chondrocyte apoptosis in cervical discs by adjusting the neck structure balance, and a more significant therapeutic effect was observed in the Tuina2 group. Lateral cervical spine X-ray and CT scans in rabbits revealed notable improvements in cervical spine curvature and vertebral structure in the treatment groups compared with those in the Model group. Hematoxylin and eosin staining and TUNEL staining further confirmed the positive impact of Tuina treatment on intervertebral disc tissue morphology and chondrocyte apoptosis. Additionally, western blotting and immunohistochemical analysis showed that Tuina treatment suppressed chondrocyte apoptosis by downregulating Bax and caspase-3 while upregulating Bcl-2. Western blotting results further indicated that Tuina could activate the FAK/PI3K/Akt signaling pathway by mediating integrin-ß1. CONCLUSION: Tuina treatment inhibited chondrocyte apoptosis in cervical discs by activating the FAK/PI3K/Akt signaling pathway, providing convincing evidence to support Tuina treatment as a promising method for IVDD.

Electroacupuncture can Modify Stress, Low-Grade Inflammation in the Duodenum, and Damage to the Intestinal Barrier in Rats with Functional Dyspepsia through the CRF Signaling Pathway

BACKGROUND: In the domain of functional gastrointestinal disorders, Functional Dyspepsia (FD) stands out due to its widespread occurrence internationally. Historically, electroacupuncture (EA) has been employed as a therapeutic modality for FD, demonstrating notable clinical efficacy. OBJECTIVES: This research aimed to delve into the impact of EA on stress responses, minor duodenal inflammatory processes, and the integrity of the intestinal barrier within FD-affected rodent models while also elucidating the underlying mechanisms. METHODS: Thirty-six male Wistar rats were evenly distributed into three cohorts: a normal, a modeled FD, and an EA treatment group. The FD condition in the rats, barring those in the normal, was induced through a series of multifactorial procedures. For the EA cohort, the rats received electroacupuncture at the acupoints RN12 (Zhongwan) and ST36 (Zusanli) for 20 minutes daily over a span of one week. The gastric residue rate (GRR), intestinal propulsion rate (IPR), and changes in emotional state were measured in each group of rats. Additionally, serum levels of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and corticosterone (CORT) were detected, and the duodenal inflammatory condition and intestinal mucosal barrier status were observed through staining and fluorescence. The expression levels of Claudin-1, Junctional Adhesion Molecule 1 (JAM-1), Corticotropin-Releasing Factor (CRF), and Corticotropin-Releasing Factor Receptor 1 (CRF-R1) were also detected. RESULTS: The study demonstrated that EA had a positive effect on body weight and food intake, GRR, and IPR in FD rats. Additionally, the EA group showed a decrease in serum levels of CRH, ACTH, and CORT, as well as a decrease in the number of duodenal mast cells and tryptase content. Furthermore, the expression of tight junction proteins Claudin-1 and JAM-1 was increased in the EA group compared to the model group. EA also reduced the levels of CRF and CRF-R1 in the hypothalamus and duodenum. CONCLUSION: EA has been shown to improve the stress state of FD rats, inhibit the activation of mast cells in the duodenum, and reduce low-grade inflammatory response and damage to the intestinal mucosal barrier. It is believed that EA achieves these effects by modulating the expression of CRF and its receptors in the brain-gut interaction pathway through the CRF signaling pathway. This provides a new approach to treating FD.

Identification of the periodontal ligament material parameters using response surface method.

The orthodontic treatment can be guided by the finite element (FE) simulation of periodontal ligament (PDL) mechanical properties, and the biomimetic degree of FE simulation can be primarily affected by the material properties of the PDL. According to the principle of parameter inverse, a method: response surface (RS) method and FE inverse method were proposed to identify the material parameters of PDL. The Prony series viscoelastic FE model was established based on the relaxation experiment. With root mean square error of simulation results and experimental results as the objective function, the optimal parameter combination was obtained by RS method, and the FE simulation result were compared with the experimental result. The result showed that the optimal parameters of the PDL were elastic modulus: 3.791 MPa, Poisson's ratio: 0.42, temperature: 29.294°C separately, and the simulation result of optimal combination maintained consistency with experiment with the correlation coefficient of 0.97258, indicating that the method proposed in this paper could well identify of PDL material parameters. The parameter identification method used in this paper can significantly improve the calculation efficiency, and reduce the parameter identification error compared with the simple FE inverse method, which has scientific significance and theoretical value.

Influence of dynamic compressive loading on the in vitro degradation behavior of pure PLA and Mg/PLA composite.

The effects of dynamic compressive loading on the in vitro degradation behavior of pure poly-lactic acid (PLA) and PLA-based composite unidirectionally reinforced with micro-arc oxidized magnesium alloy wires (Mg/PLA) are investigated. Dynamic compressive loading is shown to accelerate degradation of pure PLA and Mg/PLA. As the applied stress is increased from 0.1MPa to 0.9MPa or frequency from 0.5Hz to 2.5Hz, the overall degradation rate goes up. After immersion for 21days at 0.9MPa and 2.5Hz, the bending strength retention of the composite and pure PLA is 60.1% and 50%, respectively. Dynamic loading enhances diffusion of small acidic molecules resulting in significant pH decrease in the immersion solution. The synergistic reaction between magnesium alloy wires and PLA in the composite is further clarified by electrochemical tests. The degradation behavior of the pure PLA and PLA matrix in the composite under dynamic conditions obey the first order degradation kinetics and a numerical model is postulated to elucidate the relationship of the bending strength, stress, frequency, and immersion time under dynamic conditions. STATEMENT OF SIGNIFICANCE: We systematically study the influence of dynamic loading on the degradation behavior of pure PLA and Mg/PLA. Dynamic compressive loading is shown to accelerate degradation of pure PLA and Mg/PLA. The synergistic reaction between magnesium alloy wires and PLA in the composite is firstly clarified by electrochemical tests. The degradation behavior of the pure PLA and PLA matrix in the composite under dynamic conditions obey the first order degradation kinetics. Then, a numerical model is postulated to elucidate the relationship of the bending strength, stress, frequency, and immersion time under dynamic conditions.

In vitro degradation kinetics of pure PLA and Mg/PLA composite: Effects of immersion temperature and compression stress.

The effects of the immersion temperature and compression stress on the in vitro degradation behavior of pure poly-lactic acid (pure-PLA) and PLA-based composite unidirectionally reinforced with micro-arc oxidized magnesium alloy wires (Mg/PLA or MAO-MAWs/PLA) are investigated. The degradation kinetics of pure-PLA and the PLA matrix in MAO-MAWs/PLA exhibit an Arrhenius-type behavior. For the composite, the synergic degradation of MAO-MAWs maintains a steady pH and mitigates the degradation of PLA matrix during immersion. However, the external compression stress decreases the activation energy (Ea) and pre-exponential factor (k0) consequently increasing the degradation rate of PLA. Under a compression stress of 1MPa, Ea and k0 of pure PLA are 57.54kJ/mol and 9.74×107day-1, respectively, but 65.5kJ/mol and 9.81×108day-1 for the PLA matrix in the composite. Accelerated tests are conducted in rising immersion temperature in order to shorten the experimental time. Our analysis indicates there are well-defined relationships between the bending strength of the specimens and the PLA molecular weight during immersion, which are independent of the degradation temperature and external compression stress. Finally, a numerical model is established to elucidate the relationship of bending strength, the PLA molecular weight, activation energy, immersion time and temperature. STATEMENT OF SIGNIFICANCE: We systematically evaluate the effects of compression stress and temperature on the degradation properties of two materials: (pure-PLA) and MAO-MAWs/PLA (or Mg/PLA). The initial in vitro degradation kinetics of the unstressed or stressed pure-PLA and MAO-MAWs/PLA composite is confirmed to be Arrhenius-like. MAO-MAWs and external compression stress would influence the degradation activation energy (Ea) and pre-exponential factor (k0) of PLA, and we noticed there is a linear relationship between Ea and ln k0. Thereafter, we noticed that Mg2+, not H+, plays a significant role on the mitigation of the PLA degradation and external compression stress brings the molecular structure change of PLA. Finally, we proposed a model to predict the bending strength of the specimens versus immersion time at different immersion temperatures. This fundamental study could provide some scientific basis in our understanding for the evaluations and biomedical applications of these biodegradable materials.