Effect Of Freezing And Medicine Coordination On The Viability Of PC-3 Cells In Cryochemotherapy

Cryosurgery is a safe method of treating cancer diseases. The advantages of cryosurgery, such as eliminating the chance of bleeding from the tissue;palliation of symptoms;enhancing cryoimmunologic response, and decreasing morbidity, are obvious in these early years of clinical use. Therefore, cryosurgical techniques have received more clinical attentions for treatment of a wide variety of diseases, such as cutaneous disease, tumors, gynecologic disease, visceral disease and so on. When it is the cryosurgical treatment of prostatic cancer, some modifications in technique are needed due to the proximity of the rectum to the posterior aspect of the prostate. Cryochemotherapy, which is the administration of antineoplastic agents in conjuction with cryotherapy theoretically traps the antineoplastic drugs in the tumor thereby providing a synergistic effect. In cryochemotherapy, it is necessary to administer the appropriate drug at the appropriate time. The aim of this study is to study the effect of different administration timing of 5-FU on PC-3 cells and the apoptosis of PC-3 cells in each group at different time points in cryochemotherapy.Firstly, in the case of seeding, two different methods are investigated experimentally and the changes of PC-3 cells are observed by cryomicroscope during cooling and thawing after seeding. The results indicate that the samples are nucleated at -4℃ using seeding point of the cryomicroscope system, and at -1. 5℃ using a pre-cooled needle. But when the samples are nucleated using seeding point of the cryomicroscope system, the lid of the stage aren't removed. This can avoid the effect of air on the sample. Therefore, in the next experiments, the samples are nucleated using seeding point of the cryomicroscope system. During the process of the slow cooling, PC-3 cells shrink due to cellular dehydration. In the course of the thawing, PC-3 cells swell.Secondly, the effects of cooling rate, temperature, and thawing rate on the survival rate of PC-3 cells are studied. Additionally, the mechanism of cell death is investigated through fluorescent staining with Hoechst 33342 and PI. The results reveal that the cell viability is lowest when the cells experience faster cooling and slower thawing at -15℃. Stained cell analysis from freezing at -15℃ indicate the presence of apoptotic, necrotic, and freeze-rupture cell death. But the major reason is primarily through the freeze-rupture and the necrosis.Finally, the effect of different administration timing of 5-FU on PC-3 cells and the apoptosis of PC-3 cells in each group at different time points are investigated experimentally in cryochemotherapy. Four treatment groups are compared: cryotherapy, drugs delivered before cryotherapy, drugs delivered during cryotherapy, and drugs delivered after cryotherapy.The results reveal that drugs delivered before cryotherapy and drugs delivered after cryotherapy are better functioned. The numbers of apoptotic cells of drugs delivered after cryotherapy are higher than those of other groups.