Establishment Of The Liver Tumor Implanted Animal Model And Therapy Of E. Coli By Intratumoral Injection

Objective1 To establish a stable, simple, affordable, suitable model for screening the anti-liver tumor treatments.2 To study the anti-tumor effects of E.coli44104 by intratumoral injection.Methods1 The sarcoma 180 cell line of mice and the pGHAM-1 cell line of hamster, by tunnel implanted method, were used in the establishment of liver tumor- implanted animal model. Step 1: After recovering and centrifugation, the tumor cell of these two lines was subcutaneous injected in the right armpit of forelimb of the experiment animals. Step 2: The subcutaneous tumor (diameter≥2cm), formed in the animals, was taken out and put into the physiological saline (0-5℃) immediately, and the thriving part of tumor was taken out and cut into 0.1-0.2 cm pieces. Step 3: Under sterile conditions, the well-prepared tumor tissue, by surgery, were implanted into the left anterior lobe of liver in the experiment animals. Step 4: The biological characteristics of tumor were studied by measured the volume of tumors regularly and by the method of pathological section. The survival time of animal models were statistically analyzed. 2 The liver tumor- implanted models were divided randomly into three treatment groups and two control groups. A midline abdominal incision was performed in tumor-bearing animals, the tumor was exposed and the diameter was measured. The tumors of treatment groups and the control groups were injected with the same dosage of E.coli44104 suspensions and normal saline respectively. In the experiment, to observe the effect of E.coli44104 on tumor, experiment animals were killed, tumors were taken out, measured and observed by the histomorphology at the tenth day after treated. In the experiment, to observe the effect of E.coli44104 on survival time, from the 3rd day to 100th day after treated, the death date of the tumor -bearing animals was recorded. Finally, statistical analysis was used to the experimental data. Tumor volume, tumor suppression rate and morphological changes in tumor were compared between the experiment groups and the control group; the survival time of tumor -bearing animal was compared between the experiment groups and the control group, the conclusions were made and the potential mechanism was analyzed.Results1 97.5 percent of the S-180 liver tumor-implanted mice models and 100% percent of the pGHAM-1 liver tumor-implanted hamster models were successfully established. After implantation, the growth of tumors in the animal models was stable and quickly. From inspection of the entire cut surface, unclear interface between the tumor and normal liver parenchyma was observed; in most of tumors, gray-and-white and solid nodular was observed. During the terminal stage, the ascites and tumor metastasis were observed.2 The tumor volume, tumor suppression rate and survival time of tumor-bearing animal between the treatment groups and the control group were different. The middle-dose E.coli44104 treatment group had an obvious inhibitory effect on tumor and significantly extended bearing-animals lifespan. Pathological section showed accumulation of bacteria in the tumor of that E.coli44104 treatment group and obvious necrose and suppurate of tumor cells.Conclusions1The S-180 liver tumor-implanted mice models and the pGHAM-1 liver tumor-implanted hamster models were firstly established. These two kinds of new simple, affordable tumor models are established for the anti-tumor study.2 E. coli44104 had certain anticancer effect in the liver tumor-implanted models. This provides new experimental evidence for the anti-tumor effects of bacterial, and further investigations are worthy and needed.