Study On The Effect Of Transcatheter Arterial Chemoembolization Combining Endostatin On The Expression Of VEGF And MVD In Rabbit VX2 Hepatic Implantation Tumor

Objective:To investigate the effect on the expression of microvascular density (MVD) and vascular endothelial growth factor(VEGF) in hepatic implantation tumor after transcatheter arterial chemoembolization(TACE) combining angiogenesis inhibitor(endostatin),the correlation between MVD and VEGF,the relationship between them and the image and pathology characters in VX2 hepatic implantation tumor.To evaluate the therapeutic effect and angiogenesis of the rabbit VX2 hepatic implantation tumor.Materials and Methods:The rabbit bearing tumor was provided by Pecking Union Medical College;the New Zealand white rabbits were provided by Institute of Shandong Agricultural Science.According to the method introduced by the documents,the tumor pieces were implanted into the left lobe of the livers of the rabbits,planar sonogaphy was applied to detect the size and the growth of the tumor after implantation.When the diameter of tumors grewed to 1-2cm in models,the rabbits bearing tumor were randomly divided into three groups,with ten rabbits in each group.Group A:control group;group B:treated with transcatheter arterial chemoembolization(TACE) only;group C:treated with chemoembolization combining endostatin.The TACE were operated three weeks after the implantation. For group A,normal saline was administered via the hepatic artery;For group B, lipiodol(0.2ml/kg) and ADM(2mg/kg) were administered for every one;For group C.lipiodol(0.2ml/kg).ADM(2mg/kg) and endostatin(2mg/kg) were administered for each rabbit.The dose administered for each rabbit was identical for all three groups.Seven days after embolism,the rabbits were sacrificed and the tumors were taken out.All specimens were fixed 10%neutral formalin,embedded with paraffin completely and consecutive sections were made with a 5μm-thickness.The sections were stained by hematoxylin and eosin to demonstrate the changes of tumor morphology,and then immunohistochemistry were performed to demonstrate the expression of VEGF and CD31.The VEGF mRNA expression of tumor tissue was analyzed by RT-PCR.MSCT scanning was performed with pre- and post-contrast enhancement to observe the growth of the tumor before and after the TACE as well as before the killing of rabbits.Results:The implantation rates of all these "three groups are 100%. Morphologic observation showed the tumors are in the shape similar to round and of grey color;the cross section is similar to fish flesh.As the rapid growth of the tumor, liquefaction necrosis emerged quickly in the center of tumor.The pathological sections showed that the shape of tumor cells were irregular with big core and anachromasis,heteromorphism was obvious and nuclear fission could be seen frequently,karyoplasmic ratio was large,and the kytoplasm was abundance with carmoisine staining.Tumor stain was clearly shown by DSA.As was shown by MSCT,the tumor appeared as isodensity or low density in plain scan,circu-enhanced in arterial phase, and low density in venous phase after enhancement.After the embolism,lipiodol often deposited in ring-like shape on the edge of the tumor.The size of the tumor decreased after the treatment in group B and C,the growth rate were(-8.91±21.77%) and(-20.40±36.07%) respectively.There was no significant difference between them (P＞0.05).The tumor size in group A enlarged obviously,with the growth rate of (270.86±148.94%),and there was significant difference between this rate and the rates of the other two groups(P＜0.01).The expression of VEGF mRNA was detected by RT-PCR,two bands corresponding to VEGF121 and VEGF165 expressed respectively.As for the expression of VEGF 165,the relative light intensity of group B(1.10±0.087) was higher than that of the other two groups,and there was significant difference among them(P＜0.01).The relative light intensity of group C (0.72±0.065) was lower than that of group A(0.85±0.056).but there was no significant difference between them.As for VEGF121 mRNA,the relative light intensity of group B(1.13±0.23) was the highest,but there were no significant difference(P＞0.05) among all of the groups.VEGF protein was detected by immunohistochemistry,the expression intensity in the group B is the highest with a optical density(OD) value of 0.20±0.049 per unit area.Compared with the data of the other two groups,it had obvious differences(P＜0.01).The OD value per unit area of the group C(0.12±0.047) was lower than that of group A(0.13±0.038),but there was no significant difference between them(P＞0.05).Among the three groups the MVD of group C(57.00±13.26)was minimum,there was significant difference compared with group A(80.00±17.14) and B(84.22±16.45)(P＜0.05),and no significant difference lied between group A and B.According to correlation analysis, there was statistical correlation between VEGF and MVD among three groups (r=0.40,P＜0.05),but both of them were not correlated with the growth rate(GR) of tumor(r=-0.27,P＞0.05;r=0.16,P＞0.05).Conclusion:Rabbit VX2 hepatic implantation tumor is a tumor with sufficient blood supply.Compared with chemoembolism only,chemoembolism combining endostatin can obviously depress the expression of VEGF and lessen angiogenesis of the tumor.Both the treatments can inhibit the growth of the tumor implanted on the rabbits,and the effect of the combing method is much better.