外源性四氢生物蝶呤改善小鼠颈总动脉内膜损伤的实验研究

Tetrahydrobiopterin ameliorates the prognosis of vascular injury by increasing NO synthesis

目的:探讨四氢生物蝶呤(tetrahydrobiopterin,BH4)对血管内膜损伤修复的影响。方法:将6周龄的C57BL/6J(B6)小鼠,用专用糙面钢丝做成左侧颈总动脉内膜损伤模型,然后随机分为2组,每组12只,实验组给予20mg/kg BH4腹腔注射治疗2周,对照组给予等量生理盐水治疗。治疗2周后获取左侧颈总动脉,并以右侧颈总动脉作为对照。行苏木精-伊红染色及免疫组织化学检测观察血管内膜的变化,HPLC法检测两组受损段颈总动脉BH4水平,Western blot法检测两组血管组织eNOS表达情况,ELISA法检测两组血浆8-异构前列腺素水平和VEGF水平,Griess试剂法分析两组血浆一氧化氮(NO)水平。结果:形态学检测发现对照组有新内膜形成,并有VSMC迁移。实验组血管壁的面积明显比对照组少,两组比较差异有统计学意义(P<0.01);实验组血管组织BH4水平明显比对照组高,两组比较差异有统计学意义(P<0.01);两组血管组织eNOS表达比较差异无统计学意义(P>0.05);实验组血浆8-异构前列腺素水平明显比对照组低,两组比较差异有统计学意义(P<0.05);实验组血浆VEGF水平明显比对照组低,两组比较差异有统计学意义(P<0.01);实验组血浆NO水平明显比对照组高,两组比较差异有统计学意义(P<0.01)。结论:综合以上数据,BH4能够在不影响eNOS表达的情况下,减少实验动物血浆8-异构前列腺素及VEGF水平,促进NO合成,从而改善动脉内膜损伤的组织学表现,该研究结果为血管内膜损伤的治疗提供了一种新的策略,相关的机制需要进一步的研究支持。

Objective：To explore the effects of Tetrahydrobiopterin on the neointimal hyperplasia after vascular injury for C57BL/6J mice. Method.. C57BL/6J mice were subjected to carotid injury, and divided to two groups, and then accepted respectively intraperitoneal injection of the BH4 or saline for two weeks. The histological ap- pearance and BH4, eNOS protein expression, serum 8-isoprostane, nitrite/nitrate, and VEGF levels were meas- ured. Result：The neointimal hyperplasia and VSMC were significant in the saline group, and wall area was lower in the BH4 group than those of the saline group. The serum BH4 levels was higher in the BH4 group than those of the saline group. The nitrite/nitrate levels in the serum were significantly increased by≈2-fold in the BH4 group compared with the saline group. The free radical indicator 8-isoprostane was reduced approximately 24~ in the BH4 group compared with the saline group. The serum VEGF levels was lower in the BH4 group than those of the saline group. Western blotting showed that the level of eNOS protein between the groups was not significantly dif- ferent. Conclusion：BH4 significantly inhibited the neointimal hyperplasia after the carotid injury. This was sup- ported by the histological findings, and the mechanism was explored. According to the results, we suggested that BH4 prevents neointimal hyperplasia from vascular injury by attenuating reactive oxygen species and increasing NO synthesis and might provide a novel and promising therapeutic option for preventing vascular injury.