title: Transforming growth factor-beta1 mediates the effects of low-intensity pulsed ultrasound in chondrocytes.
abstract: Low-intensity pulsed ultrasound (LIPUS) has been shown to accelerate fracture healing, but the precise mechanism is still unknown. We used aggregate chondrocyte culture system to analyze LIPUS-induced effects on chondrocytes. First, Northern analyses revealed that LIPUS maintained higher expression levels of type II collagen and aggrecan mRNA and delayed the appearance of type X collagen mRNA expression. We also showed that DNA content was increased and that alkaline phosphatase activity was maintained low by daily treatment. Moreover, LIPUS significantly promoted transforming growth factor (TGF)-beta1 mRNA expression and the protein production at 2 h and 12 h after the treatment, respectively. Furthermore, recombinant TGF-beta1 protein mimicked the LIPUS effect and anti-TGF-beta1 neutralizing antibody reversed all these changes induced by the LIPUS treatment. These results indicate that LIPUS promotes the proliferation and retains the differentiation state of chondrocytes in the aggregate culture and that TGF-beta1 plays an important role in mediating the LIPUS effects in chondrocytes.
authors.affiliation: Department of Orthopaedic Surgery, Kyoto University, Kyoto, Japan. smukai@kyotolan.hosp.go.jp
authors.forename: Shogo
authors.initials: S
authors.lastname: Mukai
authors.forename: Hiromu
authors.initials: H
authors.lastname: Ito
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Nakagawa
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Akiyama
authors.forename: Masatomo
authors.initials: M
authors.lastname: Miyamoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D053674:Aggrecans; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism*; D024042:Collagen Type I / Q000235:genetics; D024121:Collagen Type X / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000235:genetics; D017102:Fracture Healing / Q000502:physiology; D005786:Gene Expression Regulation; D037181:Lectins, C-Type / Q000235:genetics; D011509:Proteoglycans / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D014464:Ultrasonic Therapy / Q000379:methods*; D018617:Ultrasonography, Doppler, Pulsed / Q000379:methods*
chemical_list: C508321:Acan protein, rat; D053674:Aggrecans; D000906:Antibodies; D024042:Collagen Type I; D024121:Collagen Type X; D016326:Extracellular Matrix Proteins; D037181:Lectins, C-Type; D011509:Proteoglycans; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta