Embolic effects of Bletilla striata microspheres in renal artery and transplanted VX2 liver tumor model in rabbits.

OBJECTIVE

To evaluate the characteristics of Bletilla striata microspheres (BSMs) and its effects as an embolic agent in a rabbit model.

METHODS

BSMs were prepared with an emulsifification-cool condensation-chemical cross-linking method. The characteristics of BSMs in vitro were observed. Embolization experiments were performed in renal artery of rabbit and in a rabbit liver VX2 carcinoma model. Seventy-two New Zealand rabbits were divided into 2 groups, and the right renal artery was embolized with BSMs (200 μm in diameter) in the experimental group and with polyvinyl alcohol (PVA) of the same size in the control group. The pathological findings were examined with hematoxylin-eosin and Masson stainings. Liver and renal functions were tested before and after embolization. VX2 tumor was transplanted in 15 New Zealand rabbits, which were randomly divided into 3 groups (n=5). Group A were treated with saline, group B with a mixture of doxorubicin and lipiodol, and group C with hepatic arterial infusion of BSMs (200 μm in diameter). Tumor growth rate was evaluated by magnetic resonance imaging scan. Apoptosis-related factors (bax, bcl-2) and tumor vascular endothelial cell growth factor (VEGF) were evaluated through immunohistochemical staining.

RESULTS

The characteristics of BSMs in vitro were in full compliance with the requirements for use in interventional procedures. In the renal artery embolization experiment, after BSMs intervention, it was more diffificult to form collateral circulation than that with PVAs, and the kidney manifested atrophy and calcifification. There were no signifificant difference of liver and renal functions in rabbits between groups. In the liver VX2 carcinoma embolization experiment, compared with group A, the growth rate of VX2 liver tumor and Bcl-2 levels was reduced, while apoptosis index, Bax, and VEGF were increased in group B (P<0.05). There were no signifificant difference between groups B and C (P>0.05).

CONCLUSIONS

The characteristics of BSMs in vitro and in vivo meet the requirements for its use as an embolic agent in interventional approaches.