Experimental Study On Inhibition Of VEGF Antisense Oligonucleotides On Bladder Carcinoma In Nude Mice Mediated By Ultrasound Microbubble

Objective: To investigate the effect of inhibition of vascular endothelial growth factor(VEGF)antisense oligonucleotides on human bladder carcinoma in nude mice mediated by ultrasound microbubbe.methods: 24 Balb/c nude mice were subcutaneously inoculated human bladder cancer cell line T24. The mice were randomly divided into 4 groups when transplantation tumor was established: UM+ ASODN group, liposome+ASODN group ,UM(ultrasound microbubble) group and control group,6 mice each group. For UM+ ASODN group,0.3ml mixture of microbubble and VEGF-ASODN(with 66ug VEGF-ASODN) was inject into every mice from caudal vein plus 1MHz 0.75w/cm2 ultrasound tumor local irradiation by the CGZZ gene transfection equipment. The irradiation was given 10 seconds with 10 seconds interval and the total time was 2 minutes.For liposome+ASODN group, 0.3ml mixture of liposome and VEGF-ASODN(with 66ug VEGF-ASODN) was inject into every mice from caudal vein.For UM group,0.3ml microbubble was inject into very mice from caudal vein plus local irradiation with the same condition. For control group, 0.3ml physiological saline was inject into every mice from caudal vein.The treatment was performed every 3 days with total 5 times.The tumor volume was measured regularity from the beginning of treatment.48 hours after the last treatment,separate the tumor completely; Evaluate the expression of VEGF and CD34 and Ki67 with immunohistochemistry dyeing and calculate the microvessel density (MVD) and cell proliferation index;TUNEL assay was used to analyse the apoptosis of tumor cells.Result: The growth speed of nude mice tumor in UM+ASODN group and liposome+ASODN group were obviously slower than UM group and control group.The tumor average volume in UM+ASODN group and liposome+ASODN group were 158.44±20.25mm3,176.38±19.90mm3, obviously different with UM group and control group(P<0.01);The tumor inhibition ratio in UM+ASODN group and liposome +ASODN group were 67.22% and 63.49% ;The expression of VEGF in UM+ ASODN group and liposome+ASODN group was lower than UM group and control group(P<0.05);The MVD and tumor cell proliferation index in UM+ASODN group and liposome+ASODN group was lower than UM group and control group(P < 0.05); The apoptosis index in UM+ASODN group and liposome+ASODN group was obviously higher than UM group and control group(P < 0.01),but there is no difference in each test between UM+ASODN group and liposome+ASODN group(P>0.05).Conclusion:VEGF antisense oligonucleotides mediated by ultrasound microbubbe can efficiently inhibit the growth of the nude mouse transplantation tumor with human bladder cancer.The mechanisms may be that microbubble irradiated by low intensity ultrasound can increase the permeability of the tumor tissue and cells.It can increase the transfection efficiency of VEGF antisense oligonucleotides which will inhibit the growth of tumor new vessels.