The Influence Of Interstitial Brachytherapy With ¹²⁵I Seeds On The Microvessel

The gastric tumor is one of the most digestive tract tumor which does great harm to health of the people. At present, surgical operation is a main procedure which is often combined with other methods in order to improve therapeutic efficacy. The disease is charactered with poor prognosis and higher metastasis and higher mortality. So the medical workers are looking for novel therapeutic methods all the time. because cure dosage of external irradiation is very higher than tolerance dosage of normal gastric body. The application of radiotherapy is limited,interstitial implantation of radioactive Iodine-125 seeds,one kind of brachytherapy,is a good method which can greatly injury tumor by implanting radioactive microsources which can irradiateγrays with low capacity continuously. It has many advantages:strong damage on tumor whereas normal tissue is not or slightly injured. There has derived dream therapeutic efficacy in clinical application. But its study of underlaying is less. We study on it through animal experiment and principal review radioactive iodine-125 seeds effective for tumor vessel. At the same time,the mechanism of radioactive iodine-125 seeds is explored preliminarily.PartⅠThe microvessel influence of interstitial brachytherapy with 125I seeds in the stomach cancer bare mouse transplant lumpObjective: To observes the morphological influence of interstitial brachytherapy with 125I seeds on the microvessel in nude mice with the human gastric tumorMethods: 40 nude mice models of the human gastric poorly differentiated gland BGC-823 cell tumor were established first through the injection of the cells into nude mice subcutaneously. Mice were divided into treated group and control group randomly,The 125I seeds were implanted into the tumors according to the treatment plan defined by the computer three dimensional treatment planning system (TPS) in treated group,with a prescription dose of 120 Gy. The control group was given the implantation with cold seeds. The structure of the microvessel was observed by the light microscope and electron microscope at the 15th day and the 30th day after 125I seeds implantation.Results:In the control group the number of microvessel was multitude; the vascular endothelial cell structure was manifest. The microvilli of lumen of blood vessel structure was integrity; the number of micropinocytotic vesicles was multitude on the electron microscope ; In the treated group the number of microvessel decreased obviously,the vascular endothelial cell proliferation,tumescent,felled off. The microvilli reduced,the line plastochondria was fusion,the number of micropinocytotic vesicles in the rough endoplasmic reticulum,the connective tissue become thinner on the electron microscope. There was not manifest structure change of tumors micrangium between control group and treated group after 15 days and 30days.Conclusions:The 125I seeds implantation can destruct tumor microvessel structure directly,which can inhibit the formation and growth of microvessel.PartⅡThe influence of expressions of VEGF and MVD for interstitial brachytherapy with 125I seeds in the stomach cancer bare mouse transplant lumpObjective:To observed the influence of expressions of VEGF and MVD for interstitial brachytherapy with 125I seeds on the cancer cell in nude mice with the human gastric tumorMethods:40 nude mice models of the human gastric poorly differentiated gland BGC-823 cell tumor were established first through the injection of the cells into nude mice subcutaneously. Mice were divided into treated group and control group randomly,The 125I seeds were implanted into the tumors according to the treatment plan defined by the computer three dimensional treatment planning system (TPS) in treated group,with a prescription dose of 120 Gy. The control group was given the implantation with cold seeds. The expression of VEGF and MVD which signed with CD34 were detected by immunohistochemistry at the 15th day and the 30th day after 125I seeds implantation.Results:The expression of MVD of control group and treated group after 15 days and 30days were (12.7±0.68) piece/0.72mm2,(13.5±0.97)piece /0.72mm2,(7.6±0.63)piece /0.72mm2 and 3.9±0.87piece/0.72mm2;The expression of VEGF of control group after 15 days and 30days,the positive cell were 6,6,and The expression of VEGF of treated group after 15 days and 30days,the positive cell were 3,2. The expressions of VEGF and MVD in control group were lower than the treated group at the 15th day and the 30th day (P<0.05),but there was no statistically significant differences in same group at two time(P>0.05).Conclusions:The expressions of VEGF in tumor are suppressed,and the 125I seeds implantation has the anti-tumor capillaries production function which can inhibit the formation and growth of microvessel.