Purpose: Concerns remain regarding the potential adverse effects of ultrasound contrast agents (UCA), particularly on local organs, following the identification of inflammation during the development of these agents. This study examined the expression of inflammatory genes in major organs during UCA administration and assessed their effect.

Subjects and Methods: Sprague-Dawley rats were divided into the UCA group (Sonazoid^®, 0.015 mL/kg), which received subsequent ultrasound irradiation for 10 min, and control group, which received 0.015 mL/kg of saline instead of UCA. Major organs (heart, lungs, liver, and kidneys) were excised, and the expression of monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-6, IL-10, and tumor necrosis factor-alpha (TNF-α) was evaluated.

Results and Discussion: Significantly higher levels of expression of MCP-1, IL-6, and IL-10 were observed in all organs within the UCA-treated group than in the control group, with TNF-α significantly elevated in the liver and lungs. These findings suggest that UCA administration triggers local inflammation in organs, specifically in the liver and lungs. UCA microbubble accumulation within capillaries may induce inflammation via vascular endothelial injury.

Conclusions: This study provides novel insights into the adverse effects of UCA administration on major organ localization, confirming increased inflammatory gene expression induced by UCA in major organs. Notably, the liver and lungs demonstrate more pronounced effects.