The Effects of Low Intensity Ultrasound on Chondrogenic Differentiation of Rabbit Mesenchymal Stem Cells In Vivo

In this study of using a low-intensity ultrasound (LIUS), investigated the effects of LIUS on chondrogenic differentiation of bone marrow-derived mesenchymal stem cells (BM-MSCs). The hypothesis is that LIUS may be a non-invasively effective stimulant to a biological system in vivo by turning on differentiation of MSCs and promotion of chondrogenesis. MSCs were isolated from the bone marrow of New Zealand white rabbit and cultured in monolayer for two weeks. They were then harvested and seeded into polyglycolic acid (PGA) non-woven mesh at a number of 5x106 cells and cultured with a chondrogenic-defined media for a week before in vivo implantation. In the Study I, the PGA/MSCs constructs were implanted into the subcutaneous in the back of nude mice. While ultrasound group received the direct stimulation with the LIUS in vivo for 20 min every day up to 4 weeks, control group had no LIUS stimulation. In the Study II, PGA-MSCs constructs were divided into four subgroups of the untreated control, LIUS, TGF and LIUS/TGF groups. For a week before nude mice subcutaneously implantation, the LIUS groups were subjected to ultrasound treatment for 20 min daily, the TGF groups were treated with 10 ng/ml TGF-β1. In the Study III, the PGA-MSCs constructs were divided into two subgroups of the untreated control and LIUS group. The LIUS group received the LIUS stimulation for every day 20 minutes for a week. The constructs were then implanted into the cartilage defects that were created in rabbit femoral trochlea. In the Study II and III, the chondrocytes-seeded PGA constructs served as a positive control. Analyses of gross examination, histology, biochemical assays, mechanical test and RT-PCR were made at different time point. Total DNA contents showed no significant difference between the two groups. Total collagen and glycosaminoglycan (GAG) increased more significantly in the US-stimulated group than the control. Safranin O/Fast green staining revealed that the chondrogenic differentiation of MSCs was more widespread throughout the constructs in the LIUS-treated groups. In the RT-PCR analysis before implantation, the mRNA levels of Sox-9, aggrecan and TIMP-2 were higher in the LIUS-treated groups, while those of type I and type X collagens, and MMP-13 were higher in the non-LIUS groups. In the rabbit cartilage defect model, histology and immunohistochemisty confirmed more intensive and widespread proteoglycans and type II collagen distribution in the US-preconditioned group than in the non US-treated one. This study presents that LIUS does have a great potential to stimulate the chondrogenic differentiation of MSCs in vivo without using chondrogenic growth factors.

Author dc:creator

• 최, 기호

Contributors dc:contributor

• 민, 병현
• 대학원 의학과
• 200224229

• Mesenchyamal stem cells
• chondrogenic
• preconditioning
• cartilage regeneration
• low intensity ultrasound

Language dc:language

en

Identifier

http://dcoll.ajou.ac.kr:9080/dcollection/jsp/common/DcLoOrgPer.jsp?sItemId=000000002653
000000002653

OAI identifier oai:identifier

oai:repository.ajou.ac.kr:201003/1307