OBJECTIVETo study location of MT1-MMP and effect of its change in expression on rabbit VX2 tumor tissues after transarterial embolization with hydroxyapatite nanoparticles loaded with lipiodol.

METHODSSixty rabbits implanted with tumor tissue of cell line VX2 were divided into three groups (control group, lipiodol group, hydroxyapatite nanoparticles loaded with lipiodol group). The transarterial embolization was performed super-selectively via gastro- duodenal artery of rabbits, each rabbit in control group was inserted with 1 ml normal saline,that in lipiodol group was inserted with 0.3 lipiodol ml/kg, also 0.3 ml hydroxyapatite nanoparticles loaded with lipiodol per kg for that in the last group. Results of embolization were detected by using CT scanning 3 days after operation. After two weeks, all tumors were took out as specimens to investigate location of MT1-MMP in VX2 tumor tissues,and also to determine the change of its expression in tumor tissues after embolization with different medicines, with three-step immunohistochemical technique (S-P). MT1-MMP mRNA was measured by RT-PCR to determine whether there were differences in three groups. Western blot technique was performed to determine difference of MT1-MMP protein expression of in three groups.

RESULTSImmunohistochemical results exposed that MT1-MMP was expressed on membrane of tumor cells and in extracellular matrix of tumor cells. Comparison of MT1-MMP expression in control group with that in other two groups, showed a significant lower level in control group (P < 0.05). There was no difference in MT1-MMP expression between lipiodol group, hydroxyapatite nanoparticles loaded with lipiodol group (P > 0.05). Western blot supported this conclusion. RT-PCR detecting MT1-MMP mRNA was found no differences among three groups (P > 0.05).

CONCLUSIONSMT1-MMP was mainly expressed on membrane of tumor cells and in extracellular matrix of tumor cells. There was an increasing tendency on expression of MT1-MMP in tumor tissues and extracellular matrix after transarterial embolization with hydroxyapatite nanoparticles loaded with lipiodol,it might be one of important mechanisms provoking high recurrence rate for hepatocellular carcinoma after treatment embolization.