title: Activation of transgene expression in skeletal muscle by focused ultrasound.
abstract: To correlate thermal dose from focused ultrasound (FUS) with gene expression and tissue injury, a temperature plateau strategy was employed. Plasmids encoding luciferase gene under the control of hsp70B promoter were transfected into the right gastrocnemius muscle in a rat via electroporation. One day after transfection, hind limbs were treated with 3.3-MHz focused ultrasound, using one of four different temperature plateaus with spatial-peak time-average focal temperatures (T(SPTA)) of 46 degrees C, 48 degrees C, 51 degrees C and 62 degrees C. The treatment duration at the plateau temperature was varied from 0 to 30s. Gene expression was analyzed in vivo one day following FUS treatment, and H&E staining was employed to assess tissue injury. Gene activation and tissue damage correlated closely with thermal dose. The highest level of gene activation was induced by FUS at T(SPTA)=51 degrees C for 20s, which was found to be statistically equivalent to that produced by water-bath hyperthermia.
authors.affiliation: Department of Mechanical Engineering and Materials Sciences, Pratt School of Engineering, Duke University, Durham, NC 27708, USA.
authors.forename: X
authors.initials: X
authors.lastname: Lu
authors.forename: G
authors.initials: G
authors.lastname: Sankin
authors.forename: E C
authors.initials: EC
authors.lastname: Pua
authors.forename: J
authors.initials: J
authors.lastname: Madden
authors.forename: P
authors.initials: P
authors.lastname: Zhong
mesh_terms: D000818:Animals; D015870:Gene Expression; D015316:Genetic Therapy / Q000379:methods*; D006358:Hot Temperature; D018482:Muscle, Skeletal / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015533:Transcriptional Activation; D019076:Transgenes; D014465:Ultrasonics