An improved biopsy technique for rabbits with VX2 bone tumors

Abstract

The present study aimed to investigate the efficacy of an improved biopsy method for reducing local exudation and metastasis. After resecting the VX2 tumor in cancer-bearing VX2 rabbits, a tumor cell suspension was prepared. Tumor cells were transplanted into the tibias of 20 rabbits in order to establish a bone tumor model. These adult rabbits underwent a puncture procedure after 2 weeks. All the left tibias were punctured using the improved biopsy method (the experimental group), where bolt closures were implanted into puncture holes through the metallic casing following biopsy. All the right tibias were punctured using a traditional biopsy technique (the control group). Color Doppler ultrasonography was used to assess the exudation of each puncture hole after 1 h. After 7 days, a pathological study was performed on the soft tissue near each puncture hole. The success rate of the bone model was 100% for the 20 rabbits. The exudation rate in the experimental group was lower than that in the control group (25 vs. 80%, respectively; χ²=12.13; P<0.05). The tumor-spreading rate in the experimental group was lower than that in the control group (35 vs. 85%, respectively; χ²=10.41; P<0.05). Overall, it was shown that the improved biopsy method can prevent local bleeding and tumor metastasis.

Keywords: biopsy; bone tumor; exudation; tumor metastasis.

Figure 1.

(A) Puncture instrument and (B) bolt closure.

Figure 2.

X-Rays of the tibia bone tumor of the rabbits at the first, second and third week after the VX2 tumor cells were transplanted. (A) The tumor is growing slowly in the medullary space, but the cortex of the bone is unbroken at the first week. Arrows indicate the tumor. (B) The area of the tumor destruction is larger in the second week, as indicated by the arrows. (C) The tumor is growing quickly and the cortex of the bone is destroyed partly at the third week. Arrows indicate the area of the tumor destruction.

Figure 3.

Operational process of the improved biopsy technique: 1, the metallic casing with stylet is inserted in the VX2 bone tumor; 2, the stylet is pulled out, and the casing is kept stable; 3, the needle is used to obtain the tumor tissue across the casing; 4 and 5, the bolt closures are implanted into the puncture holes through the casing after the biopsy.

Figure 4.

Representative images of exudation. (A) A certain degree of exudation (arrows) around the puncture holes in the rabbits of the control group. (B) No exudation around the puncture hole after implantation of the bolt closure (arrow).

Figure 5.

Pathological results. (A) There are no tumor cells in the muscle tissue near the puncture hole in the experimental group, only normal muscle cells (HE staining; magnification, ×20). (B) Tumor cells are present in the muscle tissue near the puncture hole in the control group; the tumor cell volume is large, with irregular cell shapes, karyomegaly, mitotic figures in certain cells and marked nucleoli staining (HE staining; magnification, ×20). HE, hematoxylin and eosin.