Low-intensity pulsed ultrasound inhibits messenger RNA expression of matrix metalloproteinase-13 induced by interleukin-1β in chondrocytes in an intensity-dependent manner. Author: Ito A, Aoyama T, Yamaguchi S, Zhang X, Akiyama H, Kuroki H. Affiliation: Motor Function Analysis, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan. Conference/Journal: Ultrasound Med Biol. Date published: 2012 Oct Other: Volume ID: 38 , Issue ID: 10 , Pages: 1726-33 , Word Count: 160 The effect of low-intensity pulsed ultrasound (LIPUS) on articular cartilage metabolism has been characterized. However, the effect of LIPUS intensity on articular cartilage degradation factors remains unknown. This study aimed to investigate the immediate effect of LIPUS at several intensities on cultured chondrocytes treated with interleukin-1β (IL-1β) to induce an inflammatory response and on articular cartilage explants. Cultured chondrocytes and articular cartilage explants were treated by LIPUS at intensities of 0, 7.5, 30 and 120 mW/cm(2) or 0, 27 and 67 mW/cm(2), respectively. mRNA analysis revealed that LIPUS inhibited induction of MMP13 mRNA expression by 100 pg/mL IL-1β in cultured chondrocytes in an intensity-dependent manner. LIPUS also inhibited MMP13 and MMP1 mRNA expression in articular cartilage explants. Our results indicate that LIPUS may potentially protect articular cartilage by inhibiting MMP mRNA expression in an intensity-dependent manner and should thus be considered a useful candidate for daily treatment of OA. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved. PMID: 22920551