The Effect Of Mitomycin Intraoperative Peritoneal Hyperthermia Chemoperfusion On Form Of Neovascularization Around Colonic Stoma Of Wistar Rat

Background and Ojective:It was a long history that people tried to use chemical medicine to cure tumor. From 1960th an accomplished system about chemotherapy began to be organized. Now many kinds of cancer could be cured by chemotherapy. Of course, tumor treatment is a comprehensive subject, it needs more experience and knowledge. Intraoperative Peritoneal Hyperthermia Chemoperfusion (Neoadjuvant Chemotherapy) is a new method on tumor treatment, which formed after 1980th. It is a local ancillary treatment after cytoreductive surgery, which combined intraperioneal chemoperfusion with local thermotherapy. Compared with the traditional chemoperfusion, IPHC has many advantages in the aspects like killing abdominal intracavitary tumor cell, minimum cancer metastastasis, prevention of tumor palindromia as well as improvement of survival rate. However, IPHC will bring cytotoxic effect on both tumor cell and normal cell. such effect is especially obvious in stoma site. It is well known that neovascularization is very important for healing of wound. This study focused on the influence of intraoperative peritoneal hyperthermia ehenmtherapy (IPHC)with mitomycin (MMC) on neovascularization in the process of healing of gastrointestinal stoma. To evaluate the safety and feasibility of IPHC.Methods:Left hemicolon mutilation and end-to-end anastomosis was performed in 54 healthy rats. All the animals were randomly divided into three groups( n=18 each group) and given different treatment as follows: Group A:37℃intraoperative peritoneal normothermaperfusion(IPNP) for twenty minutes; Group B: 43℃intraoperative peritoneal hyperthermoperfusion (IPHP) for twenty minutes and Group C:43℃IPHP with MMC 8 mg/L(IPHC) for twenty minutes.Resect colon aroundstoma on the first, third, fifth, eventh, fourteenth and twenty-eighth after the establishment of aninimal model and conduct HE and immunohistochemical dyeing,MVD,Examined VEGF-mRNA expression by using RT-PCR. Single factor analysis of variance and Pearson test was used, and significant level was established when P<0.05.Results:1.HE dyeing pathology show that novascularization of IPNH rose at 1st day , rose markedly at 3rd day , reached the peak value at 5th day , began to fall of 7th day , and had fallen towards the basic level at 28th day. The result of IPHP is agree with that of IPNP in the change of neovascularization. While IPHC rose markedly at 5th day, reached the peak value at 14th day, began to fall of after that, and had fallen towards the basic level at 28th day.2.Immunohistochemical dyeing pathology show that slightly positive expression of VEGF was seen in the vascular endothelial,fibroblastcells and partly inflammatory cells around normal colonic stoma.The VEGF protein of IPNP was positive in plasma of endothelial cells at the 1st day, and strong positive at the 5th day, and decreased gradually afeter the 7th day of the wound. The result of IPHP is agree with that of IPNP in the change of immunohistochemical dyeing. Compared with IPNH and IPHP, The VEGF protein of IPHC was positive in plasma of some endothelial cells or slightly positive partly at the 3rd day, and strong positive at the 5th and the 7th day, and positive at 14th, and then decreased after the 14th day after wound, and slightly positive expression of VEGF was seen at 28th day.3.IPNP paralleled to IPHP in the fluctuation of MVD. They rose markedly at 1st day, reached the peak value at 5th day and keeping a high level, began to fall of 7th day, and had fallen towards the basic level at 28th day. while MVD of IPHC trended to slowly, there is slight fluctuation in early postoperative period, rose markedly at 3rd day, reached the peak value at 14th day, began to fall of after that, and had fallen towards the basic level at 28th day. Compared IPHP with IPNP, significant differences were only showed in 1st day. There were no significant differences in the other postoperative period between IPNP and IPHP;Compared IPHC with IPNP, There were significant differences in each times except 7th,28th days.4.With MVD being enhanced, VEGF expression being increased in each experimental group. Compared IPHP with IPNP, significant differences were only showed in 1st day,There were no significant differences in the other postoperativeperiod between IPNP and IPHP. Compared IPHC with IPNP, There was significant differences in each times except 7th,28th days. Pearson test showed that VEGF expression was significantly correlated with MVD. (r1=0.92 p1<0.01; r2=0.97 p2<0.01; r3=0.94 p3<0.01 )Conclusions:1.Hyperthermia impairs generate of neovascularization around colonic stoma, which are confined to early postoperative period. MMC combined with Hyperthermia for IPHC might aggravate this inhibition to the process of generate of neovascularization. The synergic effects is showed remarkably and lastingly.2.Neovascularization around colonic stoma increase a high level at 7 th day after operation in each groups, and there were no significant differences in each groups. So we can presume that it is critical time for the healing of stoma.3 . VEGF has specific function in promoting mitosis growth of vascular endothelial cells and is an effective endogenetic vascular growth factor in rat. VEGF is correlated with colonic neovascularization after colocolic anastomosis. VEGF plays a very important role in the formation of neovascularization of colonic stoma.4. Hyperthermia combined with MMC for IPHC has a detrimental effect on transcription and expression of VEGF in molecular level, which impairs generate of neovascularization around colonic stoma.