半叶马尾藻多糖对小鼠S180肉瘤的抑制作用及其机制

Therapeutic Effect of Seaweed Polysaccharide from Sargassum Confusum on Sarcoma S180 in Mice and Its Mechanism

背景与目的:由于目前使用的化疗药物在肿瘤治疗中副作用较大,严重制约了化疗药物在肿瘤治疗方面的应用。本实验目的是研究野生半叶马尾藻多糖(SP)对S180肉瘤小鼠肿瘤生长的抑制作用和机制,为寻找低毒和高效的治疗肿瘤药物提供有价值的实验资料。方法:称重法检测SP对小鼠S180肉瘤的抑瘤率,流式细胞术分析SP对S180肉瘤小鼠胸腺细胞和脾淋巴细胞周期的影响,3H-TdR和3H-TyR掺入法测定S180肉瘤小鼠胸腺细胞、脾淋巴细胞DNA合成及蛋白质合成,脾淋巴细胞转化实验检测SP对S180肉瘤小鼠的免疫增强作用。结果:在肿瘤接种前10天给予小鼠SP50、100和200mg/kg,抑瘤率分别为28.7%、32.9%和50.3%,其中100mg/kg和200mg/kg的SP组与NS对照组比较抑瘤率有显著性差异(P<0.05)。小鼠接种肿瘤细胞后,脾脏和胸腺明显缩小,其脏器指数与正常对照组比较有显著性差异(P<0.05)。SP可以缓解小鼠脾淋巴细胞和胸腺细胞在接种肿瘤细胞后发生的G1期阻滞。各浓度SP组小鼠胸腺细胞3H-TdR掺入值显著高于NS对照组。200mg/kgSP组小鼠脾细胞DNA合成及100mg/kg和200mg/kgSP组小鼠脾细胞蛋白质合成显著高于NS对照组,说明SP对肿瘤接种后引起的小鼠脾细胞DNA和蛋白质合成显著降低也有拮抗作用。各浓度SP组刀豆素A(concanavalinA,ConA)和脂多糖(lipopolysaccharide,LPS)诱导的小鼠脾淋巴细胞增殖显著高于NS对照组。结论:SP对S180肉瘤小鼠肿瘤生长有抑制作用,其机制可能是通过提高小鼠的脾淋巴细胞和胸腺细胞的数量和功能而实现的。

BACKGROUND ＆ OBJECTIVE： Previous chemotherapeutic drugs have side effects which restrict their application in treating tumors. This research was to explore the inhibitory effect of wild Seaweed Polysaccharide from Sargassum confusum （SP） on sarcoma S180 xenograft in mice and its mechanism to offer experimental basis for searching for antitumor drugs with high efficiency and low toxicity. METHODS; SP were prepared and injected abdominally in mice at the doses of 50, 100, and 200 mg/kg, respectively, for 10 days before tumor cell transplantation. The mice with injection of 0.85% normal saline were set as negative control. The weight of S180 xenografts in mice was measured to calculate the inhibitory rate of SP on S180 tumor; the cell cycle of thymocytes and splenocytes were measured by flow cytometry （FCM）; DNA and protein syntheses in thymocytes and splenocytes were measured by incorporation of ^3H-TdR; the immunopotentiative effect of SP on mice was assessed by splenic lymphocytes transformation assay. RESULTS： The inhibitory rates of S180 xenografts in mice treated with 50, 100, and 200 mg/kg SP were 28.7%, 32.9%, and 50.3%, respectively. The thymocytes and splenocytes functions were significantly enhanced in SP groups than in control group （P〈0.05, P〈0.01）. CONCLUSIONS, SP might inhibit the growth of S180 xenograft in mice through improving the functions of thymocytes and splenocytes.