四氢生物蝶呤促进胃腺癌发展及淋巴管生成的作用

Role of tetrahydrobiopterin in gastric adenocarcinoma progression and lymphangiogenesis

摘要:

目的：探讨外源性四氢生物蝶呤（tetrahydrobiopterin，BH4）对BALB/c-nu小鼠MNK-45胃腺癌皮下移植瘤生长的影响。方法：体外培养人胃癌细胞MNK-45，建立人胃癌MKN-45裸小鼠皮下移植瘤模型。随机分为BH4组和生理盐水组，每组5只。BH4组给予BH4腹腔注射（20 mg/kg），每天1次，生理盐水组给予等量生理盐水，共给药2周。给药期间记录肿瘤体积变化，给药结束后脱颈椎处死小鼠，剥离肿瘤测量称重。分别采用免疫组织化学染色法检测肿瘤组织诱导型一氧化氮合酶（inducible nitric oxide synthase，iNOS）及D2-40染色程度，Western blot检测iNOS蛋白表达，Greiss法检测一氧化氮（nitric oxide，NO）含量及ELISA法检测BH4含量。结果：BH4组肿瘤体积明显大于生理盐水组（P＜0.001）。且BH4组肿瘤组织内BH4含量、NO浓度、iNOS表达及D2-40表达均明显高于生理盐水组（P＜0.05）。结论：BH4可能通过偶联iNOS导致NO合成过量，诱导淋巴管生成，进而促进胃腺癌发展。

Abstract:

Objective：To investigate the effect of exogenous tetrahydrobiopterin on the growth of subcutaneous tumor graft of MNK-45 gastric adenocarcinoma in BALB/c-nu mice. Methods：Human gastric cancer cell MKN-45 was cultured in vitro，and a subcutaneous transplanted tumor model of human gastric cancer MKN-45 was established in nude mice. Randomized groups were divided into BH4 group and saline group，each with 5 rats. The BH4 group were injected intraperitoneally with BH4（20 mg/kg），once a day for two weeks. Equal volumes of saline were injected in saline group. The changes in tumor growth during treatment were observed. After the treatment，the mice were killed by removing the neck cone，and the tumor was stripped and weighed. The staining extent of inducible nitric oxide synthase（iNOS） and D2-40 was evaluated with immunohistochemical staining，the protein expression was detected with Western blot，nitric oxide（NO） content was determined by Greiss reaction and BH4 content was determined by ELISA analysis. Results：The tumor size in BH4 group was significantly greater than that in saline group（P<0.001）. The contents of BH4 and NO in tumor tissue，and the expression of iNOS and D2-40 were significantly higher in BH4 group than those in saline group（P<0.05）. Conclusion：BH4 may enhance excessive NO synthesis by coupling iNOS，and then induce lymphangiogenesis and promote tumor growth in gastric adenocarcinoma.