Localized delivery of compounds into articular cartilage by using high-intensity focused ultrasound

Sci Rep. 2019 Nov 4;9(1):15937. doi: 10.1038/s41598-019-52012-z.

Abstract

Localized delivery of drugs into an osteoarthritic cartilaginous lesion does not yet exist, which limits pharmaceutical management of osteoarthritis (OA). High-intensity focused ultrasound (HIFU) provides a means to actuate matter from a distance in a non-destructive way. In this study, we aimed to deliver methylene blue locally into bovine articular cartilage in vitro. HIFU-treated samples (n = 10) were immersed in a methylene blue (MB) solution during sonication (f = 2.16 MHz, peak-positive-pressure = 3.5 MPa, mechanical index = 1.8, pulse repetition frequency = 3.0 kHz, cycles per burst: 50, duty cycle: 7%). Adjacent control 1 tissue (n = 10) was first pre-treated with HIFU followed by immersion into MB; adjacent control 2 tissue (n = 10) was immersed in MB without ultrasound exposure. The MB content was higher (p < 0.05) in HIFU-treated samples all the way to a depth of 600 µm from AC surface when compared to controls. Chondrocyte viability and RNA expression levels associated with cartilage degeneration were not different in HIFU-treated samples when compared to controls (p > 0.05). To conclude, HIFU delivers molecules into articular cartilage without major short-term concerns about safety. The method is a candidate for a future approach for managing OA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cartilage, Articular / chemistry
  • Cartilage, Articular / metabolism*
  • Cattle
  • Cell Survival / drug effects
  • Chondrocytes / cytology
  • Chondrocytes / metabolism
  • High-Intensity Focused Ultrasound Ablation*
  • Matrix Metalloproteinases / genetics
  • Matrix Metalloproteinases / metabolism
  • Methylene Blue / chemistry
  • Methylene Blue / metabolism
  • Methylene Blue / pharmacology
  • Osteoarthritis / metabolism
  • Osteoarthritis / pathology
  • Osteoarthritis / veterinary
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta / metabolism

Substances

  • Transforming Growth Factor beta
  • Matrix Metalloproteinases
  • Methylene Blue