In Vivo Low-Intensity Pulsed Ultrasound (LIPUS) Following Tendon Injury Promotes Repair During Granulation but Suppresses Decorin and Biglycan Expression During Remodeling

Abstract

Low-intensity pulsed ultrasound (LIPUS) has been shown to be effective in promoting tendon healing in different animal models of tendon injuries, [3][4][5][9][10][11]14 but the mechanism is not completely understood. In vitro studies on cultured tendon fibroblasts from intact tendons indicated that ultrasound could stimulate collagen production 16 t meTHoDS: In a rat model of patellar tendon donor site injury, a single sonication of LIPUS or mock sonication was delivered to the injured knee of the rats on the fourth, 14th or 28th day postinjury. Tendon samples were harvested at 4 hours and 24 hours after sonication and the mRNA expression of COL1A1, COL3A1, decorin, biglycan, and TGF-beta 1 was analyzed.t reSuLTS: The results showed that a single sonication of LIPUS increased COL1A1 and COL3A1 mRNA in healing patellar tendons when administered on the fourth or 14th day postinjury, but not when administered on the 28th day postinjury. Both decorin and biglycan mRNA were decreased by treatment with LIPUS on the 28th day postinjury. Our results showed that LIPUS enhanced collagen synthesis in vivo only during the granulation phase. Matrix remodeling may be affected by LIPUS with the suppressed expression of decorin and biglycan.t ConCLuSion: Our findings suggest that LIPUS should be applied during the granulation phase but not during the remodeling phase, to promote tendon healing.

Low-intensity pulsed ultrasound promotes cell motility through vinculin-controlled Rac1 GTPase activity

“…Many in vivo studies have demonstrated that LIPUS can be beneficial in improving healing in several other tissue types, including the skin wounds of diabetic and aged mice by increasing fibroblast migration into the wound site (Roper et al, 2015), ischemic heart disease by increasing angiogenesis (Hanawa et al, 2014), tendon repair (Jeremias Junior et al, 2011;Lu et al, 2016) by increasing collagen synthesis (Fu et al, 2010), and muscle repair after injury by increasing myofibre regeneration .…”

Low Intensity Ultrasound for Promoting Soft Tissue Healing: A Systematic Review of the Literature and Medical Technology

“…27,28 Additionally, an examination of treatment time and duration found that introducing LITUS in the earlier stages of healing increased tensile strength and matrix synthesis compared to the later stages of healing. 21,29 In three human studies examining epicondylitis and patellar tendinopathy, tendon pain was significantly decreased in a clinically meaningful way by up to 70% with daily applied continuous LITUS over the course of 6 weeks, 47 although in two of the studies pulsed LITUS produced similar decreases in pain with the control groups. 11,14 …”

Low-Intensity Pulsed Ultrasound Accelerates Healing in Rat Calcaneus Tendon Injuries

“…7,14,15 In addition, it has been shown that low-intensity pulsed ultrasound has a positive effect on tendon healing. 14,15,35 Although many results are encouraging, the influence of ultrasound on the structural properties of healing tendons is far from being universally agreed upon. 22 Among parameters that influence treatment effectiveness, particular attention must be given to current intensity.…”

“…In vitro and in vivo studies have shown that therapeutic ultrasound promotes formation and maturation of healing tissues 26 through increased protein synthesis, 8,27 increased fibroblast proliferation, 6,28 increased growth factor release, 16,30 angiogenesis, 36 and collagen reorganization. 3,14,17 Its most significant benefits occur during the inflammatory, granulation, and proliferative phases of the healing process. 7,14,15 In addition, it has been shown that low-intensity pulsed ultrasound has a positive effect on tendon healing.…”

“…3,14,17 Its most significant benefits occur during the inflammatory, granulation, and proliferative phases of the healing process. 7,14,15 In addition, it has been shown that low-intensity pulsed ultrasound has a positive effect on tendon healing. 14,15,35 Although many results are encouraging, the influence of ultrasound on the structural properties of healing tendons is far from being universally agreed upon.…”