冰片对H2受体介导组胺开放血脑肿瘤屏障的作用及机制

The treatment of intracranial malignant tumors is not satisfied because it is difficult for drugs to enter the tumor tissue due to the existence of blood-brain tumor barrier (BTB). This study is the further research about the effect and mechanism of borneol on the open of BTB based on its aromatic resuscitation function and the previous results that borneol could increase the content of irinotecan into the brain. The mRNA expressions of H2 receptor in tumors of model rats implanted with cells of C6, RG2, 9L glioma and NCI-H250 brain metastatic small cell lung cancer are detected, and the open of BTB is also observed after borneol administration. The histamine concentration in model rats brains is determined in the use of microdialysis coupled with high performance liquid chromatography -electrochemical detector after borneol administration. The mRNA expressions of H2 receptor in four kinds of BTBs in vitro are detected respectively, and their permeabilities are also observed through two ways of paracellular pathway and transcellular transport after histamine intervention. This study will clarify the function and mechanism of borneol openning BTB selectively mediated by histamine-H2 receptor. It will provide basis for the study of combination of borneol with chemotherapeutic drugs in clinic, and provide experimental proof for H2 receptor as molecular marker for individual combined administration. The results of this study will open a new way for the treatment of intracranial malignant tumors.

由于血脑肿瘤屏障存在，药物不易进入肿瘤组织，颅内恶性肿瘤治疗效果差。本项目基于冰片的"芳香开窍"作用及前期研究结果"冰片可促进化疗药伊立替康进入脑内"，进一步研究其对血脑肿瘤屏障开放的作用及分子机制。测定移植性C6、RG2、9L胶质瘤和NCI-H250脑转移性小细胞肺癌模型大鼠肿瘤组织的H2受体mRNA表达水平，观察冰片作用后血脑肿瘤屏障开放情况；脑微透析-HPLC-电化学偶联技术在体测定冰片作用后模型大鼠脑内组胺的动态变化；测定四种体外血脑肿瘤屏障的H2受体mRNA表达水平，从细胞旁路和跨细胞转运两条途径观察组胺作用后各屏障通透性的变化。通过本项目研究，将阐明冰片选择性开放BTB的作用及其组胺-H2受体途径介导机制，为临床开展联合应用冰片和化疗药物研究奠定基础，并为H2受体表达作为个体化联合用药的分子标志物提供实验依据。本项目研究成果将为颅内恶性肿瘤治疗开辟新途径。

由于血脑肿瘤屏障存在，药物不易进入肿瘤组织，颅内恶性肿瘤治疗效果差。建立C6、RG2和9L大鼠颅内移植瘤模型、裸鼠颅内SCLC移植瘤模型以及制作了伊文氏蓝含量标准曲线，通过伊文思蓝实验提示冰片开放血脑肿瘤屏障（blood-brain tumor barrier, BTB）的程度与BTB上H2受体平均光密度具有较好的一致性。通过微透析实验显示冰片联合化疗药物伊立替康与单用伊立替康比较能增加组胺的释放。分别取C6、RG2、9L脑胶质瘤细胞与脑微血管内皮细胞共培养建立体外BTB模型，从细胞旁路和跨细胞转运两条途径观察各屏障在组胺作用后的开放情况及机制，结果显示组胺可开放BTB并能被H2受体拮抗剂西咪替丁抑制，组胺开放BTB的作用与下调紧密连接相关蛋白的表达有关，组胺开放BTB程度与H2受体有一定的相关性。本项目的研究成果为临床开展联合应用冰片和化疗药物研究奠定基础，并为颅内恶性肿瘤的中西医结合治疗提供新思路。本项目资助下培养硕士研究生2名，已发表SCI论文1篇，其他英文论文1篇，中文核心期刊论文2篇，中文核心期刊综述2篇，授权国家发明专利1项，参加国际学术交流2次。