| The malignant tumor is a serious risk to human health disease. The usually treatment is surgical operation, and it is a comprehensive treatment assisted by chemical therapy, radiation therapy and immune therapy. The chemical therapy plays an important role in the treatments of cancer. The traditional chemical therapy play a certain role on the killing of tumor cells through systemic drugs injecting. However, it also has great toxic side effects, the patients can not bear it. So in recent years, more and more researches attend to directly kill the tumor and avoid the systemic side effects, including local injection, sustained-release implants ,controlled-release implants and so on. The choice of chemical treatment drugs maybe possible as the medical polymer materials development. It ensures a more stable local drug concentration and lighten the toxic side effects by combination with the biodegradable polymer materials. The experiment take PEG750- PLLA as the carrier. PEG750-PLLA is a copolymer of poly-L-lactic acid and polyethylene glycol whose molecular weight is 750. It is a synthetic biodegradable polymer materials. It has a good biocompati- bility and has no toxic side effect. Its degradation products of lactic acids and glycolic acids can attend in human metabolism, then eventually excreted out as the form of carbon dioxide and water. We used electrospinning technology to implant matrix vector adriamycin, Each unit biodegradable electrospun fiber contains 0.1mg doxorubicin,The ADM-fiber has been made. Our experiments have confirmed that the adriamycin sustained-releasing system has higher anti ectogenetic tumor cells. But its effects on the alive tumor tissue are not clear. The article observed the anti-tumor effect of the copolymer of poly-L-lactic acid and polyethylene glycol implanted in tumors with the expectation of providing experimental evidences and theoretical basis'of clinical application.Methods:1. Establishment of rat tumor model50 rats which was incubated C57BL for 7 days were included in the study. Cell concentration of 2×107/ml in ascites was injected into left posterior limbs subcutaneously. 1 week later the model was established.2. Animal groupsThe rats were divided into 4 groups with 10 rats each.Male and female was the same. (1)experimental group:Adriamycin delayed release system was implanted into rats. (2) control group 1:0.1mg Adriamycin diluted by 100uL saline was injected into the tumors.; (3) control group 2:0.1mg Adriamycin diluted by 100uL saline was injected into the rat by tail vein. 4) control group 3:Salin was injected into the rat by tail vein. In the period of experiment rats were fed with food and water.3. Tumor growth rate and inhibitory rate1,3,6,9,13 days later tumor long diameter and short diameterwere measured by vernier caliper. According to the formula:tumor volume (V) =long diameter×(tumor short diameter2/2. On the 14th day rats were killed and tumor samples were resected and weighed, then calculate the tumor inhibitory rate.4. Pathological changeRats H22 tumors were fixed by 10% formalin, routine dehydration, paraffin-embedded, slice up, HE staining, optic microscopy (×100), at last tumor necrosis was observed.5. Immunohistochemistry analysis of cell apoptosis-related protein Rats H22 tumors were fixed by 10% formalin,routine dehydration, paraffin-embedded, slice up. Immunohistochemistry staining was done by caspase-3 and Fas with rabbit anti human polyclonal antibody and ABC kit.After enveloping it, caspase-3 and fas positive cell numbers were observed by microscopy×200 in 100 cells.6. Cell apoptosis rate examinationRat H22 tumors were assimilated into cells fluid,fixed and PI staining. Tumor cell apoptosis was examined by FCM(BD carlibur,US).Apoptosis rate = subduplation numbers×100%/total duplation.7. Statistical analysisAll data was expressed by mean±SD, The computer software SPSS12.0 was used in the analysis of data.Results:1. Tumor size change and inhibitory rateTumor size was examined from first drug admistration to killing rats. On 6th day tumor size of experimental group and control group 1 are smaller than control group 2 and 3, and the difference is significant statistically (P>0.05). On the 9th and 13th day tumor size is smaller than control group, and the difference is significant statistically (P<0.05). On the 14th day, tumors were dissected from rats,weighed and calculated the inhibitory rate. Tumor inhibitory rate of experimental group is higher than that of control group (P<0.01).2. Pathological changeTumor samples were done immunohistochemistry staining. Tumor necrosis extent of experimental group is severe and expressed as +++, and control group 1 and 2 is ++ and control group 3 is+.3. Cell apoptosis examinationFas is a protein inducing apoptosis,and caspase-3 plays an important role in apoptosis.Their expression is positive relevant with cell apoptosis extent. Caspase-3 and Fas positive cells of experimental group is more than those of control groups (P<0.01). By FCM tumor cell apoptosis rate of experimental group is 24.21%±0.05 which is higher than that of control group which is 15.67%±0.03,control group 2 is 15.04%±0.02 and control group 3 is 10.90%±0.01 (P<0.01). |
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