The aim of this study was to investigate the longitudinal effects of electroacupuncture (EA) on Zusanli (ST36) and Ashi acupoints in promoting skeletal muscle regeneration and inhibiting excessive fibrosis after contusion in rabbits. Sixty rabbits were randomly divided into four groups: normal, contusion, EA, and recombinant human insulin-like growth factor-I (rhIGF-I). An acute skeletal muscle contusion was produced on the right gastrocnemius (GM) by an instrument-based drop-mass technique. EA was performed for 15 minutes every two days with 0.4 mA (2 Hz), and GM injections were executed with rhIGF-I (0.25 mL once a week). Rabbits treated with EA had a higher T-SOD and T-AOC serum activities and lower MDA serum level, the blood perfusion of which was also significantly higher. In the EA group, the diameter of the myofibril was uniform and the arrangement was regular, contrary to the contusion group. The number and diameter of regenerative myofibers and MHC expression were increased in the EA group. EA treatment significantly decreased fibrosis formation and reduced both GDF-8 and p-Smad2/3 expressions in injured muscle. Our data indicate that EA may promote myofiber regeneration and reduce excessive fibrosis by improving blood flow and antioxidant capacities. Additionally, EA may regulate signaling factor expression after contusion.

Polytetrafluoroethylene/Poly(methyl methacrylate) (PTFE/PMMA) composite was prepared by mixing PTFE into PMMA matrix which synthesized by the PMMA powder mixture and methyl methacrylate (MMA) liquid mixture. The effects of the filling mass ratio of PTFE and powder/liquid (P/L) ratio on the friction and wear properties of PTFE/PMMA composites against bearing steel were studied by a ball-on-disk tribometer. Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDS) were used to characterize the synthesis of PTFE/PMMA composite. The shore hardness and glass transition temperature (Tg) were obtained respectively by shore hardness tester and differential scanning calorimetry (DSC). The results show that the friction coefficient and wear rate of PMMA based composite, comparing with the unfilled PMMA, can be significantly reduced by filling with PTFE. With the increasing of PTFE filling mass ratio, the wear rate of PTFE/PMMA composite increases. The friction coefficient and wear rate of the unfilled PMMA and PTFE/PMMA composite generally decrease with the P/L ratio increasing. The main wear mechanism of the unfilled PMMA is adhesive wear. While the main wear mechanisms of PTFE/PMMA composites are fatigue wear and abrasive wear.

Introduction: Currently, many clinical experiments are being conducted to study the effect of acupuncture on skeletal muscle contusions, and its therapeutic effect has been confirmed to some extent. However, the mechanism of recovery by electroacupuncture (EA) in skeletal muscles after blunt trauma remains unknown. Objective: To determine whether EA at Zusanli can contribute to the regeneration of contused skeletal muscle and the molecular mechanism involved. Methods: Masson’s trichrome staining and hematoxylin and eosin staining were used to measure the area of fibrotic tissue and determine the number of centrally nucleated muscle fibers respectively. The different immune phenotypes of macrophages were determined by flow cytometry. Then, ELISA was used to analyze the levels of interleukin-4 (IL-4), IL-6, interferon-α (IFN-α) and interferon-γ (IFN-γ) in the injured tissue. Finally, the expression of MyoD in the tissue was detected by quantitative real-time polymerase chain reaction. Results: EA at Zusanli helped regenerate contused skeletal muscle by alleviating fibrosis and increasing the size of the regenerating myofibres in the injured skeletal muscle. EA at Zusanli increased the number of M2 macrophages and decreased the number of M1 macrophages in contused skeletal muscle. EA at Zusanli decreased the level of cytokine IFN-γ and increased the levels of IL-4, interleukin-13 (IL-13), and IFN-α, which promoted macrophage polarization during the fibrosis recovery process in the contused skeletal muscle. EA at Zusanli could increase the expression of MyoD in tissues. Conclusions: EA at Zusanli promoted macrophage polarization during the fibrotic process in contused skeletal muscle by decreasing cytokine IFN-γ and increasing IL-4, IL-13, and IFN-α, which contributed to the regeneration of the contused skeletal muscle.

Orientations and weaves played an important role in the friction reduction and antiwear properties of PTFE/Kevlar fabric composite.