Recruitment of mesenchymal stem cells and expression of TGF-$beta;1 and VEGF in the early stage of shock wave-promoted bone regeneration of segmental defect in rats

Abstract

Extracorporeal shock wave (ESW) treatment has recently been established as a method to enhance bone repair. Here, we reported that ESW-promoted healing of segmental defect via stimulation of mesenchymal stem cell recruitment and differentiation into bone forming cells. Rats with a segmental femoral defect were exposed to a single ESW treatment (0.16 mJ/mm?, 1 Hz, 500 impulses). Cell morphology and histological changes in the defect region were assessed 3, 7, 14, and 28 days post-treatment. Presence of mesenchymal stem cell was assayed by immuno-staing for RPS9, a recently discovered marker, and also production of TGF-PI and VEGF was monitored. ESW treatment increased total cell density and the proportion of RP59 positive cells in the defect region. High numbers of round-and cuboidal-shaped cells strongly expressing RPS9 were initially found. Later, the predominant cell type was spindle-shaped fibroblastic cells, subsequently, aggregates of osteogenic and chondrogenic cells were observed. Histological observation suggested that bone marrow stem cells were progressively differentiated into osteoblasts and chondrocytes. RP59 staining was initially intense and decreased with the appearance of expression depended on the differentiation states of osteogenic and chondrogenic cells during the regeneration phase. Mature chondrocytes and osteoblasts exhibited only slight RP59 immunoreactivity. Expression of TGF-PI and VEGF-A mRNA in the defect tissues was also significantly increased ( P < 0.05) after ESW treatment as determined by RT-PCR. Intensive TGF-PI immuno-reactivity was induced immediately, whereas a lag period was observed for VEGF-A. Chondrocytes and osteoblasts at the junction of ossified cartilage clearly exhibited VEGF-A expression. Our findings suggest that recruitment of meseoblasts at the junction of ossified cartilage clearly exhibited mesenchymal stem cells is a critical step in bone reparation that is enhanced by ESW treatment. TGF-P1 and VEGF-A are proposed to play a chemotactic and mitogenic role in recruitment and differentiation of mesenchymal stem cells.

Shock Wave Treatment Enhances Cell Proliferation and Improves Wound Healing by ATP Release-coupled Extracellular Signal-regulated Kinase (ERK) Activation

“…Our findings with these different cell types suggest that ESWT may aid tissue repair by influencing the inflammatory and regenerative aspects of wound healing. The effects of shock waves on primary human stem cells suggest that clinical ESWT may promote the growth and perhaps the differentiation of stem or progenitor cells during tissue regeneration (1,(57)(58)(59). In all three cell types we tested in vitro, we found a uniform scheme of shock wave-induced ATP release, subsequent stimulation of purinergic receptors, and the activation of Erk1/2 signaling, finally resulting in enhanced cell proliferation.…”

Extracorporeal Shock Wave Treatment Improves Incisional Wound Healing in Diabetic Rats

“…Increasing the endogenous release of growth factors is one potential mechanism by which ESWT facilitates tissue repair. Up-regulation of TGF-β1 expression following ESWT has been observed in various cell types, such as dermal fibroblasts (Berta et al 2009), tenocytes (Chen et al 2004a), mesenchymal stem cells, chondral cells and osteoblastic cells (Chen et al 2004b). In the proliferative phase, TGF-β1 is mainly released from fibroblasts.…”

Effects of shock wave therapy in the skin of patients with progressive systemic sclerosis: a pilot study

“…It has been recently demonstrated that, in addition to angiogenesis due to migration and proliferation of endothelial cells in situ, EPCs contribute to neovascularization in ischemic tissue through a vasculogenetic mechanism and through secretion of a variety of angiogenic factors [18][19]. Finally, recent studies have marked out that ESW are able to recruit stem cells and to stimulate their differentiation in various damaged tissues inducing reparative phenomena [20][21][22].…”