Study Of Bio-distribution And Imaging For ⁹⁹Tc^m Labeling Anti-Zheng's Plant Protein(⁹⁹Tc^m-ZPPAb) In Bearing H₂₂ Hepatocarcinoma Mice

Objective:Application of radionuclides ⁹⁹Tc^m labeled anti-Zheng's plant protein antibody(⁹⁹Tc^m-ZPPAb),to study the biodistribution of ⁹⁹Tc^m-ZPPAb in bearing H₂₂ hepatocarcinoma mice, and make mice imaging with radioimmunoimaging principle, and evaluate the practicability of ⁹⁹Tc^m-ZPPAb as a new imaging agent of positive tumors.Methods : 1. Imaging agent labeling method and determination of labeling rate of imaging agent. ZPPAb was labeled with ⁹⁹Tc^m by the "pretinning" method. The labeling method and process of normal rabbit IgG was same as ZPPAb. The determination of labeling rate of imaging agent. In the system of Ethanol:H2O:Amonia (2:5:1) -filter paper,the RF value of every ingredient: ⁹⁹Tc^m-ZPPAb was 0.6⁰.9, ⁹⁹Tc^m-Colloid was 0,⁹⁹Tc^mO4 was 0.6⁰.9. In the system of physiologic saline - filter paper , the RF value of every ingredient: ⁹⁹Tc^m-ZPPAb was 0, ⁹⁹Tc^m-Colloid was 0,⁹⁹Tc^mO4 was 1.0.2. The biodistribution experiment of bearing H₂₂ hepatocarcinoma mice. 84 bearing H₂₂ hepatocarcinoma mice were randomly divided into 4 group, each group was 21. Experimental group and control group were injected ⁹⁹Tc^m-ZPPAb and normal rabbit ⁹⁹Tc^m-IgG 0.2ml(7.4MBq) through the tail intravenous, improved experimental group and improved control group were injected alb before above-mentioned two kinds of imaging agent. Each group mice were killed with orbital blood at 0.5h,1h,2h,3h,4h,5h,6h after injection of imaging agent. Dissect to gain the heart,liver,spleen,lung,kidney,stomach,small intestine,bone,blood,tumor tissue and the contralateral hindlimb muscle. These tissue were weighted and counted,and the percentage of radioactivity administered dose per gram of tissue(%ID/g) and ratio tumor to non-tumor(T/NT) were used to express the isotope retention.3. The imaging experiment of bearing H₂₂ hepatocarcinoma mice. 12 bearing H₂₂ hepatocarcinoma mice were randomly divided into 4 group, each group was 3. They were experimental group,control group,improved experimental group and improved control group. Experimental group and control group were injected ⁹⁹Tc^m-ZPPAb and normal rabbit ⁹⁹Tc^m-IgG 0.2ml (7.4MBq) through the tail intravenous, improved experimental group and improved control group were injected alb before above-mentioned two kinds of imaging agent. They were imaging at 0.5h,1h,2h,3h,4h,5h,6h after injection of imaging agent. And calculate the ratio tumor to the contralateral hindlimb muscle(T/NT) with the same ROI technique in imaging. Results: 1.The labeling rate of ⁹⁹Tc^m-ZPPAb:The labeling rate of ⁹⁹Tc^m-ZPPAb was 70%,the radiochemical purity of ⁹⁹Tc^m-ZPPAb was than 80 % after the G15 dextran gel purification column.2. The biodistribution experiment of bearing H₂₂ hepatocarcinoma mice. The %ID/g of kidney was highest in experimental group, The %ID/g of tumor tissue was second. The maximum %ID/g of tumor tissue was 0.93%ID/g at 5h after injection of imaging agent. The %ID/g of kidney was high,the maximum %ID/g of kidney was 23.03%ID/g at 5h after injection of imaging agent. The %ID/g of liver was similar with tumor tissue. The %ID/g of stomach and small intestine was very low. The results of improved experimental group was similar with experimental group,only the %ID/g of improved experimental group tumor tissue was lower than the experimental group,the maximum %ID/g of tumor tissue was 0.438%ID/g at 1h after injection of imaging agent. Analyzed the tumor tissue %ID/g of different groups,the result was significantly different(F=13.49,P<0.01),then compared each tow groups,the result showed that between experimental group respectively and control group,improved experimental group,improved control group was significantly different(P<0.01).In experimental group,the T/NT of tumor to kidney was low all the way,the T/NT of tumor to muscle was gradually increased,the maximum was 8.89 at 6h after injection of imaging agent. In improved experimental group,the T/NT of tumor to muscle was between 2.8 and 5.24,the maximum was 5.24 at 3h after injection of imaging agent. Analyzed the T/NT of tumor to muscle of different groups , the result was significantly different(F=23.69,P<0.01),then compared each tow groups,the result showed that between experimental group respectively and control group,improved experimental group,improved control group was significantly different(P<0.01),between improved experimental group respectively and control group,improved control group was significantly different (P<0.01). The T/NT was significantly different between experimental group and control group,and the %ID/g of tumor still exist higher uptake in improved experimental group,it showed that there was specific uptake on the tumor tissue;The T/NT was significantly different between experimental group and improved experimental group,it showed that there was non-specific uptake on the tumor tissue.3. The imaging experiment of bearing H₂₂ hepatocarcinoma mice. In experimental group and improved experimental group,the tumor site of mice was imaging at 0.5h after injection of imaging agent. The tumor site radionuclide concentration on the most obvious at 3h after injection of imaging agent in experimental group , after the tumor site radionuclide concentration gradually decreased. In control group and improved control group imaging, there was radionuclide concentration image only on the abdomen and bladder site,but there was not obvious radionuclide concentration image on left hindlimb tumor site. And calculate the ratio tumor to the contralateral hindlimb muscle(T/NT) with the same ROI technique in imaging. In experimental group,the maximum T/NT value was 6.04 at 3h after injection of imaging agent,after the T/NT was gradually decreased. The T/NT of improved experimental group was lower than experimental group,the maximum T/NT was 5.75 at 4h after injection of imaging agent.Conclusion:This study showed that there was specific uptake with ⁹⁹Tc^m-ZPPAb on the tumor tissue in bearing H₂₂ hepatocarcinoma mice. ⁹⁹Tc^m-ZPPAb could stagnate for a period of time in the tumor tissue to facilitate imaging. ⁹⁹Tc^m-ZPPAb can be conveniently labeled with the satisfactory labeling rate, and it was the advantages that the labeling radionuclide and imaging equipment was generally. ⁹⁹Tc^m-ZPPAb was expected to become a potential new positive tumor imaging agent.