Expression of VEGF and apoptosis of tumor cells in different regions of VX2 tumor in rabbit liver after radiofrequency ablation / 中国介入影像与治疗学

ABSTRACT

Objective To explore the expression of vascular endothelial growth factor (VEGF) and apoptosis of the tumor cells in the different regions of rabbit liver VX2 tumor after radiofrequency ablation (RFA).Methods Forty-eight experimental rabbits were implanted with VX2 tumor.After successfully established the model,the rabbits were randomly divided into control group (n=6) and RFA group (n=42).In the RFA group,7 rabbits at each time point were killed at immediately,1 day,2 days,1 week,2 weeks,3 weeks after RFA,and the tumor specimens were retained and performed with HE staining,VEGF,Annexin V-FITC/PI labeling,flow cytometry analysis.The changes of VEGF and apoptosis of the cells in different periods and different zones after RFA were observed.Results After the operation,the difference of the VEGF value of the needle zone,coagulation necrotic zone and junction zone had statistically significant (all P＜0.05).The difference of the VEGF value in each zone between immediately and the other time points after operation by pairwise comparisons were significantly different (all P＜0.05).The VEGF value of the needle zone and coagulation necrotic zone reached the peak after operation immediately,which declined from 1 day to 3 weeks after operative.And VEGF of the junction zone increased from immediately to 1 week after operation,and declined 2 weeks after operation.There were significant differences in the apoptosis rate of the three zones after RFA compared with control group (all P＜0.05).The apoptosis rate in all zones were at the peak on the 1 day after operation,and then showed a downward trend.Conclusion The reduction of VEGF and apoptosis of tumor cells in the needle zone and coagulation necrotic zone are significant,but tumor remnant remains visible in the junction zone.In the third week after RFA,the proliferation of the remaining tumor cells can be recurrent to preoperative levels,which suggests that the further treatment should be performed at this period.