title: Pulsed and Continuous Ultrasound Increase Chondrogenesis through the Increase of Heat Shock Protein 70 Expression in Rat Articular Cartilage.
abstract: [Purpose] The present study was aimed to investigate the effects of pulsed and continuous ultrasound (US) irradiation on heat shock protein (HSP) 70 and mRNA levels of chondrogenesis-related gene expression in rat tibial articular cartilage. [Subjects and Methods] Forty-eight rats with body weights of 200-250 g were randomly divided into three groups. In the control (CON) group, three rats were treated with sham sonication. The pulsed US irradiation group was irradiated with a pulse rate of 20%, a frequency of 1 MHz, and an intensity of 1.5 W/cm(2) for 10 minutes. The continuous US irradiation group was continuously with a frequency of 1 MHz and an intensity of 1.5 W/cm(2) for 10 minutes. Immunohistochemistry for evaluation of HSP 70 and RT-PCR for expression of the chondrogenesis-related mRNA were used. [Results] The expression of HSP70 protein was increased in the pulsed and continuous US groups. The increase in the continuous US group was more prominent than in the pulsed US group. In addition, pulsed and continuous US irradiation increased the expression of Mustn1 and Sox9. [Conclusion] The results of this study show that US increases chondrogenesis via the increase of HSP 70 and chondrogenesis-related mRNA expressions in rat articular cartilage.
authors.affiliation: Department of Physical Therapy, College of Health and Welfare, Dongshin University, Republic of Korea.
authors.forename: Ki Won
authors.initials: KW
authors.lastname: Nam
authors.affiliation: Department of Physical Therapy, Graduate School of Dongshin University, Republic of Korea.
authors.forename: Dong Yel
authors.initials: DY
authors.lastname: Seo
authors.affiliation: Department of Physical Therapy, College of Health Science, Eulji University, Republic of Korea.
authors.forename: Min Hee
authors.initials: MH
authors.lastname: Kim
keywords: Articular cartilage; Heat shock protein 70; Ultrasound