Apoptosis is activated in an early period after radiofrequency ablation of liver tissue.
OBJECTIVE
Hyperthermia induced apoptosis may lead to tumor cell death thus expanding the volume of non-viable tissue and warrant a "safety margin" of at least 10mm to exclude the possibility of tumor recurrence. We carried out an experimental study to investigate the cellular injury produced by radiofrequency ablation in the area surrounding the ablated tissue and to describe early apoptotic processes in the transition zone following radiofrequency ablation procedure in a porcine liver model.


METHODS
Nine anesthetized pigs underwent laparotomy and local thermal ablation of the liver parenchyma. The ablated tissue and the surrounding parenchyma were investigated for apoptosis applying Western blot analysis and immunohistochemistry.


RESULTS
The active (cleaved) caspase-3 17-kDa subunit was detected in the transition zone one hour after ablative procedure at a distance of 9-10 mm from the rim of the necrosis zone. In contrast analysis of tissues in necrosis zone and in surrounding normal liver parenchyma revealed no markers of apoptotic activity.


CONCLUSIONS
We determined that apoptosis, leading to further cell death, is activated in the majority of cells in the transition zone, thus supporting the hypothesis that the "safety margin" of 10 mm is encompassed by the indirect thermal effect.
Vanagas
Tomas
T
Department of Surgery, Kaunas University of Medicine Hospital, Eiveniu 2, Kaunas LT-50009, Lithuania. tvanagas@gmail.com
Gulbinas
Antanas
A
Sadauskiene
Ilona
I
Dambrauskas
Zilvinas
Z
Pundzius
Juozas
J
Barauskas
Giedrius
G
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D017115:Catheter Ablation; D007150:Immunohistochemistry; D008099:Liver / Q000473:pathology* / Q000601:surgery*; D013552:Swine