The Experimental Study On Iodine-125 Interstitial Brachytherapy In Hepatoma

Objective To investigate the inhibitory effect of the iodine-125granule of different dosage, in vitro, upon the growth of the humanhepatoma cell line BEL-7402,(and to obtain the growth curve of the cellline). In this study, the animal models of the BEL-7402 tumor wereestabilished first through the injection of the cells into nude micesbcutaneously, followed by the implant of the iodine-125 granule ofdifferent dosage into the tumor mass. By this method, not only theefficiency of the therapy can be verified, but the relative vailableIn of thetherapeutic dosage of iodine-125 can be indicated. The mechanism of theiodine-125 inducing the apoptosis of the tumor cell was also concerned.In a word, we tried to find a new, effective strategy in coping with theclinically middle-advanced or recurrent hepatoma. Methods First, made the growth curve of the BEL-7402 cell linebasing on MTT (or: cell counting) method results, which indicate theimpact of the iodine-125 granule of different dosage upon the BEL-7402cell growth. At the same time, the value of IC50 were also recorded.Second, the animal tumor model estabilished precedently were dividedinto five groups (one group contains 6 nude mice), each group receivingthe different dosage of iodine-125 granule respectively (high-, middle-,low-, zero-, control). The width and length of tumor, in order to caculatethe volume, were measured every four days till four weeks, when thetumor mass were dissected for the further examination such asimmuhistochemical stain (VEGF, PCNA, p53), TUNEL (to find thedegree of apoptosis induced by the different dosage of iodine-125), andelectron microscope (to find the morphological change of the positiondifferent distance away from the irradiation granule ). Results The IC50 of BEL-7402 is 0.6mCi. In the in vivo study, theinhibitary rate by different dosage in the BEL-7402 nude mouse tumor model 4 重庆医科大学博士研究生学位论文were 41.31%,30.53%,14.59% respectively. The expression of VEGF,PCNA in iodine-125 group were found significantly lower than thecontrol. At the same time, the phenomenon of high degree apoptosis werefound in iodine-125 group. As for the expression of P53, there wasremarked difference between the treatment and the control group, and thesame result was also observed between the high/middle dosage and thelower dosage group. Conclusions 1.This study verifies the efficiency of the iodine-125granule in inhibiting the growth of hepatoma cell, which offered theexperimental evidence that it can be a potent strategy in the clinicaltherapy of HCC, especially for those being in terminal stage, those beingof surgery contraindication, those being of postoperative reccurence, andthose suffering the histological non-negative dissection edge. 2.This studyalso indicates that the dosage vailableIn of iodine-125 is between 0.4 and0.8 mCi, which is of a little difference from that we adapted nowadays(between 0.3 and 0.5mCi). 3.Iodine-125 interstitial brachytherapy lowersthe expression of VEGF and PCNA as well as induces the expression ofP53.