The effect of hepatic radiofrequency ablation on stem cell trafficking in the rat model.

Purpose: To determine whether radiofrequency (RF) ablation causes increased hepatic embryonic stem cell trafficking in the rat liver model.

Materials And Methods: Right hepatic lobe RF ablation was performed in rats for 5 minutes at 15 minutes (n = 2) and 48 hours (n = 2) before administration of rat hepatic embryonic stem cells (rhESCs). Green fluorescent protein-labeled rhESCs were injected intravenously, and all rats were killed 5 days after rhESC injection. Tissue was removed from RF ablation areas and untreated liver, the latter of which served as control. Slides were evaluated with fluorescent microscopy, and software fluorescence count was performed for evaluation of rhESC distribution. Regions of rhESC destination were divided into inner coagulation (zone A), periablational (zone B), and peripheral (zone C) zones. Fluorescence comparison was additionally performed between RF ablation areas and corresponding control tissues of the left hepatic lobe (segment II). Kruskal-Wallis testing was used for evaluations.

Results: Fluorescent pixel count was significantly higher in RF ablation areas than in respective controls: mean at 15 minutes, 10,471 +/- 3,830 (SD) versus 1,889 +/- 1,427 (P < .05); mean at 48 hours, 15,177 +/- 7,091 versus 2,868 +/- 1,714 (P < .05). High-power field samples showed significant distribution differences across zones: zone B, mean, 1,015.4 +/- 311; zone A, mean, 17.8 +/- 11; and zone C, mean, 141.2 +/- 51.4 (P < .05).

Conclusions: RhESCs administered after RF ablation are trafficked to the periablational margin in significantly greater numbers than the remaining liver.