Ultrasound Enhances Transforming Growth Factor β-Mediated Chondrocyte Differentiation of Human Mesenchymal Stem Cells

Abstract

In clinical studies and animal models, low-intensity ultrasound (US) promotes fracture repair and increases mechanical strength. US also promotes cartilage healing by increasing glycosaminoglycan synthesis of chondrocytes. As mesenchymal stem cells (MSCs) have the ability to differentiate into chondrocytes, US may promote their differentiation. Here, we evaluated the effects of US on the differentiation of MSCs toward chondrocytes and cartilage matrix formation. When human MSCs cultured in pellets were treated with transforming growth factor beta (TGF-beta, 10 ng/mL), they differentiated into chondrocytes as assessed by alcian blue staining and immunostaining for aggrecan, but nontreated cell pellets did not. Furthermore, when low-intensity US was applied for 20 min every day to the TGF-beta-treated cell pellets, chondrocyte differentiation was enhanced. Biochemically, aggrecan deposition was increased by 2.9- and 8.7-fold by treatment with TGF-beta alone, and with both TGF-beta and US, respectively. In contrast, cell proliferation and total protein amount appeared unaffected by these treatments. These results indicate that low-intensity US enhances TGF-beta-mediated chondrocyte differentiation of MSCs in pellet culture and that application of US may facilitate larger preparations of chondrocytes and the formation of mature cartilage tissue.

A mechano-regulatory model for bone healing predictions under the influence of ultrasound

“…The osteoblast density was also found to be about 10% greater in the ultrasound model from PFW1 to PFW4, which is also reported in previous experimental studies [50][51][52][53][54]. Nevertheless no safe conclusions can be drawn for this enhancement influence since this is downstream effect and has not been explicitly modeled herein.…”

Low‐intensity Ultrasound Stimulation Enhances Chondrogenic Differentiation in Alginate Culture of Mesenchymal Stem Cells

“…Recently, Ebisawa et al showed that the LIUS treatment enhanced the TGF-β-mediated aggrecan deposition in pellet culture of human MSC (10). However, no further details on LIUS effects such as the changes in the expression of collagen type II and other related proteins were suggested in their experiment.…”

“…Among them, TGF-β is known as a critical factor for initiation of chondrogenic differentiation in vitro and in vivo (5,7). TGF-β1 was used originally in the chondrogenic differentiation of chondrocytes and MSCs (2,8), but TGF-β2 or TGF-β3 were also shown to be effective in MSCs (5,9,10). In addition to the protein factors, mechanical factors such as cyclic compressive loading and three-dimensional (3-D) culture system are also known to induce chondrogenesis of MSCs in vitro (2,3,(11)(12)(13).…”

Low Intensity Pulsed Ultrasound: A Laboratory and Clinical Promoter in Tissue Engineering Abstract

“…Also, LIPUS was used for 20 minutes for one day to stimulate MSCs expansion and differentiation into chondrocytes. Matrix production was enhanced; however, cell proliferation was not enhanced (Ebisawa et al, 2004). This may also be due to using LIPUS in pellet culture.…”