title: [Effect of thermo-sensitive Matrigel on minimization of thermal injury to the nearby structures in radiofrequency ablation of subcapsular hepatic tumors in a rat model].
abstract: OBJECTIVE
  To evaluate the effect and safety of using thermo-sensitive Matrigel as artificial ascites on minimizing thermal injury to the nearby structures in a rat model of radiofrequency (RF) ablation of the liver.
  
  
  METHODS
  In this research, the morphological characterization of Matrigel was observed at different temperatures in vitro. In vivo study was conducted by using 42 SD rats in Matrigel, Saline and control groups of 14 rats each. Artificial ascites with 10 ml of Matrigel or saline was produced under ultrasound guidance before RF in the experimental groups. Using a 0.7 cm exposed 17 G RF electrode for 5 minutes (90 ± 2) ℃, 41 hepatic ablations was performed abutting the diaphragm, abdominal wall and stomach. The 41 rats were sacrificed at 24 h, and necropsy was performed.Gross and histopathologic examinations were performed to compare the frequency and extent of thermal injury to the nearby organs.The animal status was followed up to achieve long term safety evaluation of Matrigel.
  
  
  RESULTS
  Matrigel was in liquid formation at 0-4 ℃, but was not moving in vials at temperature 37 ℃ in 1 min, presenting gel formation.In vivo experiment, the artificial fluid thickness of Matrigel in site was significant larger than that of saline group, especially at 5 min of ablation ((8.1 ± 1.1) mm vs (2.4 ± 0.8)mm, P<0.01). Thermal injury to the nearby structures was found in 12 of 13 cases in control group, 8 of 14 cases (P=0.037) in saline group, and 1 of 14 cases (P<0.01) in Matrigel group. The sizes of the ablation zone of the liver did not differ among the three groups. There was no difference in the incidence of operation related complications among the three groups. There was no significant difference in body weight and health related parameters between Matrigel and saline group during 60 days of follow up.
  
  
  CONCLUSIONS
  Using thermo-sensitive Matrigel as artificial ascites may be a safe and useful technique and help to further reduce the frequency and severity of collateral thermal injury to the nearby structures compare to conventional saline, during RF ablation of subcapsular hepatic tumors.
authors.affiliation: Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education), Department of Ultrasound, Peking University Cancer Hospital and Institute, Beijing 100142, China.
authors.forename: J J
authors.initials: JJ
authors.lastname: Fu
authors.forename: S
authors.initials: S
authors.lastname: Wang
authors.forename: R H
authors.initials: RH
authors.lastname: Guan
authors.forename: W
authors.initials: W
authors.lastname: Yang
authors.forename: K
authors.initials: K
authors.lastname: Yan
authors.forename: M H
authors.initials: MH
authors.lastname: Chen
mesh_terms: D000818:Animals; D001201:Ascites; D017115:Catheter Ablation; D003094:Collagen; D003964:Diaphragm; D004195:Disease Models, Animal; D004338:Drug Combinations; D004566:Electrodes; D007797:Laminin; D008113:Liver Neoplasms; D011509:Proteoglycans; D051381:Rats; D017207:Rats, Sprague-Dawley; D012965:Sodium Chloride; D013270:Stomach
chemical_list: D004338:Drug Combinations; D007797:Laminin; D011509:Proteoglycans; C059485:matrigel; D012965:Sodium Chloride; D003094:Collagen