癌症化學治療通常被用來對付無法用手術去除的癌細胞，不過在接受癌症化學治療的過程中，會對病人產生不良的副作用，影響病人健康。真菌幾丁聚醣(Chitosan)為真菌類細胞壁中的主要成分。研究發現幾丁聚醣具有許多生物活性作用，如增進免疫功能、保護腸胃道及抑制腫瘤細胞生長等。本研究的目的在探討真菌幾丁聚醣對於癌症化學治療所產生的副作用是否有改善的效果，且不影響癌症化療藥物的抗癌效果，並探討其相關的機制。首先利用動物實驗模式，以骨髓毒性、胃腸毒性、免疫功能作為副作用指標，來評估真菌幾丁聚醣對於癌症化學治療藥物(5-氟尿嘧啶，5-FU) 所引發的副作用是否有改善的效果。小鼠實驗中單獨以5-FU給藥及5-FU合併真菌幾丁聚醣方式給藥，藉由測定腫瘤體積與重量、骨髓中CD 19細胞百分比、血液中白血球與淋巴球數量、小腸蔗糖酶活性、腹瀉發生率、微核試驗及彗星分析來評估抗癌效果、副作用發生情形和相關機轉的探討。研究結果顯示，5-FU合併真菌幾丁聚醣給藥並不影響5-FU抑制癌細胞生長的效果。真菌幾丁聚醣減輕了由5-FU所造成骨髓中CD 19百分比及血液中白血球與淋巴球細胞數量的下降情形。5-FU合併真菌幾丁聚醣可以降低小腸黏膜受到損害及延緩小鼠腹瀉的發生率。在微核測驗與彗星分析結果中顯示出5-FU合併真菌幾丁聚醣減少了5-FU對於正常細胞染色體與DNA的傷害。由實驗結果推論，真菌幾丁聚醣可能經由降低5-FU對於正常細胞之DNA傷害，而改善了5-FU所誘發骨髓毒性、免疫毒性與腸胃毒性之副作用。

　Cancer chemotherapy is used to treat tumor cells that can not be removed by surgery. In the process of treatment, however, cancer chemotherapy often induces side effects and reduces health of cancer patients. Chitosan is the main component of the fungi’s cell wall. Chitosan has several biological activities such as immuno-enhancing ability, protection mucosa damage in gastrointestinal track and anti-tumor activity. The purpose of this study was to investigate whether Chitosan could improve the side effects induced by chemotherapeutic agent without loss its anti-tumor ability and their related mechanisms. The study examined the anti-tumor activity and side effects (meylotoxicity, immunotoxicity and gastrointestinal toxicity) of combined treatment of chemotherapeutic drug 5-Fluorouracil (5-FU) and Chitosan in vivo. We measured the weight and volume of tumor, percentage of CD19 in bone marrow, leukocyte number, lymphocyte number, sucrase activity, incidence of diarrhea, micronucleated polychromatic erythrocytes (MNPCE) frequency and Comet assay in mice treated with 5-FU plus Chitosan or 5-FU alone to evaluate the effects of Chitosan on the 5-FU-induced anti-tumor activity and side effects. The results showed that 5-FU plus Chitosan inhibited the tumor growth as well as 5-FU alone. Chitosan improved the reduction of leukocyte number, lymphocyte number and CD19 percentage of bone marrow induced by 5-FU. 5-FU combined with Chitosan reduced the injury of the small intestinal mucosa and delayed the onset of diarrhea in mice. 5-FU combined with Chitosan also decreased MNPCE frequency and DNA damage caused by 5-FU in bone marrow cells. The results demonstrate that Chitosan may improve adverse effects induced by 5-FU through reduction DNA damage of normal cell.

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