【摘要】： 目的探索雙歧桿菌對腫瘤的抑制作用，并從信號轉(zhuǎn)導這一層次探索青春雙歧桿菌的抑瘤途徑。 方法將青春雙歧桿菌體外直接作用于大腸癌LoVo細胞，以MTT法、流式細胞儀法和免疫細胞化學方法分別測定了雙歧桿菌對腫瘤細胞的殺傷作用及其對腫瘤細胞周期、細胞凋亡、酪氨酸激酶(PTK)的活性以及核因子(NF-κB)的活化狀況的影響。 結(jié)果本實驗中MTT結(jié)果顯示雙歧桿菌對體外培養(yǎng)的大腸癌LoVo細胞具有明顯的生長抑制作用，且雙歧桿菌的濃度越大、作用時間越長，其對腫瘤的抑制作用越強，具有濃度和時間依賴性。經(jīng)濃度為1×10~7CFU／ml的青春雙歧桿菌作用72h后，其對大腸癌LoVo細胞的生長抑制率達到52％，經(jīng)濃度為1×10~(11)CFU／ml的雙歧桿菌作用72h后，，其對大腸癌LoVo細胞的生長抑制率達到78％(P0．05)。流式細胞儀檢測發(fā)現(xiàn)，濃度為1×10~9CFU／ml的雙歧桿菌作用48h后能將腫瘤細胞阻滯于G_0／G_1期，在細胞周期G_1峰的左側(cè)出現(xiàn)了凋亡峰。流式細胞儀法檢測細胞凋亡發(fā)現(xiàn)，雙歧桿菌具有誘導大腸癌細胞凋亡的作用與細胞周期所得結(jié)果一致，腫瘤對照組細胞凋亡率為(9．48±0．91)％，經(jīng)濃度為1×10~7CFU／ml的雙歧桿菌作用48h后，腫瘤細胞的凋亡率為(26．37±2．41)％，經(jīng)濃度為1×10~9CFU／ml的雙歧桿菌作用48h后，腫瘤細胞的凋亡率為(40．99±1．66)％(P0．05)。雙歧桿菌作用組PTK的熒光強度顯著低于腫瘤對照組(P0．01)，表明雙歧桿菌能降低大腸癌LoVo細胞PTK的活性。免疫組細胞化學結(jié)果顯示，雙歧桿菌作用組的NF-κB的表達明顯低于腫瘤對照組(P0．05)。 結(jié)論本實驗發(fā)現(xiàn)雙歧桿菌對腫瘤細胞具有生長抑制作用，可以誘導大腸癌LoVo細胞凋亡，將腫瘤細胞阻滯在G_1期，同時降低腫瘤細胞PTK的活性，抑制NF-κB的活化。雙歧桿菌抑制腫瘤的途徑可能通過誘導腫瘤細胞凋亡及影響腫瘤細胞信號轉(zhuǎn)導途徑中的關(guān)鍵信號分子的活性與表達。圖[17]表[5]參[59]
[Abstract]:Objective to explore the inhibitory effect of Bifidobacterium on tumor and explore the inhibition pathway of Bifidobacterium pubertii from signal transduction level. Methods Bifidobacterium pubericiae was directly exposed to colorectal cancer LoVo cells in vitro. The killing effect of bifidobacterium on tumor cells, cell cycle and apoptosis were determined by MTT, flow cytometry and immunocytochemistry, respectively. Effects of tyrosine kinase (PTK) activity and activation of NF- 魏 B. Results the results of MTT showed that Bifidobacterium could inhibit the growth of LoVo cells in vitro, and the higher the concentration of Bifidobacterium, the longer the time of action, the stronger the inhibitory effect of Bifidobacterium on the tumor. It is concentration-dependent and time-dependent. After 72 hours of treatment with 1 脳 10~7CFU/ml Bifidobacterium pubernum, the growth inhibition rate of LoVo cells reached 522%. After 72 hours of treatment with 1 脳 10 ~ (11) CFU/ml Bifidobacterium, the growth inhibition rate of LoVo cells was 78% (P0.05). Flow cytometry showed that Bifidobacterium at concentration of 1 脳 10~9CFU/ml could block tumor cells in G_0/G_1 phase after 48 h, and apoptosis peak appeared on the left side of cell cycle G _ (1) peak. The results of flow cytometry showed that Bifidobacterium could induce the apoptosis of colorectal cancer cells, and the apoptosis rate of tumor control group was (9.48 鹵0.91). The apoptotic rate of tumor cells was (26.37 鹵2.41) after exposure to 1 脳 10~7CFU/ml bifidobacterium for 48 h, and (40.99 鹵1.66)% (P0.05) after 48 h treatment with 1 脳 10~9CFU/ml Bifidobacterium. The fluorescence intensity of PTK in Bifidobacterium treated group was significantly lower than that in tumor control group (P0.01), which indicated that Bifidobacterium could reduce the activity of PTK in LoVo cells of colorectal cancer. The expression of NF- 魏 B in the bifidobacterium treated group was significantly lower than that in the tumor control group (P0.05). Conclusion Bifidobacterium can inhibit the growth of tumor cells, induce the apoptosis of LoVo cells, block the tumor cells in G _ 1 phase, decrease the activity of PTK and inhibit the activation of NF- 魏 B. Bifidobacterium inhibits tumor cells by inducing apoptosis and affecting the activity and expression of key signal molecules in the signal transduction pathway of tumor cells. Fig [17] Table [5] Ref [59]
【學位授予單位】：安徽理工大學
【學位級別】：碩士
【學位授予年份】：2008
【分類號】：R371;R735.34

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