| The growth of malignant tumor is dependent on angiogenesis. And the growth, infiltration, metastasis of primary tumor all need angiogenesis, therefore, the therapeutics of anti-angiogenesis of tumor has been come a hot point in the therapeutics study of tumor recently. But the therapeutics of anti-angiogenesis also has some unsolved problems. For example, it is still doesn' t has a good method to choose a proper case for the treatment. It is to say, we can' t conform exactly who should get beneficial from the therapy and we still no good ways to value the effect of this therapy. Since 1994 when the angiostatin was detected by 0 Reilly, it has attracted people' s notice because of the powerful anti-angiogenesis and anti-metastasis role. The current study has shown it has a highvalue in clinical using. This study labels AS with 99Tcm and try to establish an imaging method of angiogenesis, using for value the effect of anti-angiogenesis therapy. At the same time, it can offer a strong tool for the further study of AS.AIMTo explore the method of 99Tcm direct labeling angiostatin (AS) and investigate the stability and bioactivity of wTc'-AS in vitro ; observe the distribution in mice bearing tumor and explore the value of 99Tcm-AS in assessment of antiangiogenic effect and positive imaging of tumor .METHODS1. The extracted AS was validated, and then labeled with 99Tcm after having been reduced by 2-ME or SnCl2. The best labeling condition was screened by cross design.2. The labeling efficiency of the production was measured by thin layer chromatography(TLC) and validated by column chromatography. TLC supported by Newhua filter paper in saline. Rf : 99Tcm-AS =0.0, 99Tcm colloid =0.0, 99TcmO4-=1.0;3. The stability of the products were evaluated in bovine serum albumin (BSA) , saline and cysteine(Cys).4. We detected the bioactivity of 99Tcm-AS by inhibition experiment of vessel endothelial in ECV304 cell line.5. Tissue distribution studies and scintigraphic imaging studies: One blocking experiment was performed to identify whether has a competitive inhibition effect in the combination of 99Tcm-AS and tumor. Pretreated the Balb/c mice bearing EMT6 tumor 2hbefore injection of drug and make saline as control. Observed the distribution and imaging in mice at different time point when drug was injected.6. Statistics method: Significance test of mean value with t test and analysis of variance in SPSS software. We also used cross design in the screening of optima conditions.Results1. the optimum condition as follows , 2-ME approach: AS100 u g, PB(0.5M, pH7. 3)lml,2-MEl00ug, MDP 10 ul, added 99TcmO4-185MBq, the labeling efficiency can up to 97?. 5%; SnCl2 approach: added AS100 ug, boric acid buffer ( 0. 1 M, pH9. 0) 1 ml to the reaction bottle, 2% SnCl2( including IN hydrochloric acid) 20 u 1 , added into MDP, which is diluted with 1ml deoxygenized water, and then took 20ul ,and added 99TcmO4- 185MBq, the labeling efficiency can achieve 90+3.0%.2. The radioactivity associated with the 99Tcm-AS declined by 2% after 6h-competition with 10g/l BSA, declined by 1. 5% in saline. The radioactivity can be decreased in different molar ratios of Cys. The radioactivity decreased by 2% when the molar ratio was 5 and below. This indicates that the product is stable in vitro.3. Treated cells with AS and 99Tcm-AS in various dosage , took 0. 2 M 6- aminocaproic acid as control and the results indicated that the biological activity of suppressing endothelial cells of 99Tcm-AS was not significantly different with AS .4. Study of distribution in mice indicates: the radioactivity distribution decreased with prolong of time in both blocking andno blocking groups except in tumor. The uptake in liver and kidney is high and in lung and muscle is low. In blocking group, the tissue radioactivity distribution mostly decreased except liver and muscle. After 4h of the drug injection, the radioactivity distribution in blood, small intestine, heart, liver, lung and tumor is significance difference(p<0. 05)...
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