颅内新型隐球菌感染对血-脑屏障乳腺癌耐药蛋白功能的影响

Effect of intracranial Cryptococcus neoformans infection on the function of efflux transporter breast cancer-resistance protein

目的探索颅内新型隐球菌感染对血-脑屏障上外排蛋白乳腺癌耐药蛋白(BCRP)转运氟康唑功能的影响。方法健康雄性SD大鼠24只,随机分为4组。A组:正常大鼠静脉给予氟康唑;B组:正常大鼠静脉给予氟康唑+BCRP抑制剂泮托拉唑;C组:大鼠采用颅内接种法建模后静脉给予氟康唑;D组:大鼠建模后静脉给予氟康唑+泮托拉唑。各组大鼠纹状体植入微透析探针,静脉给药后,连续采集脑细胞外液(间隔20min,采集至给药后300min)及外周血(给药后5、10、15、30、45、60、90、150、210、300min)标本。采用高效液相色谱技术测定标本中氟康唑浓度并绘制浓度-时间曲线,计算曲线下面积(AUC)及氟康唑血-脑屏障透过率,并进行组间比较。结果采用颅内接种法成功建立了新型隐球菌脑膜脑炎大鼠模型。新型隐球菌感染可明显提高氟康唑的血-脑屏障透过率(P<0.05)。BCRP抑制剂泮托拉唑未改变正常大鼠氟康唑的血-脑屏障透过率,但明显提高了模型大鼠氟康唑的血-脑屏障透过率(P<0.05)。结论颅内新型隐球菌感染可破坏血-脑屏障的结构功能,BCRP抑制剂有助于提高血-脑屏障对氟康唑的透过率,但同时也削弱了血-脑屏障对神经毒素或其他有害外源物质的屏障作用,其临床应用的安全性及有效性仍须深入研究。

Objective To explore the effect ofintracranial Cryptococcus neoformans （Cr. neoformans） infection on the function of fluconazole transport by breast cancer-resistance protein （BCRP）, a kind of efflux transporter on the blood-brain barrier （BBB）. Methods Twenty-four male Sprague-Dawley rats were randomly divided into 4 groups （6 each）： normal rats received 20mg/kg fluconazole by intravenous injection （Group A）, normal rats received 20mg/kg fluconazole with co-administration of pantoprazole （a kind of BCRP inhibitor） by intravenous injection （Group B）, rats with intracranial Cr. ncoformans infection received 20mg/kg fluconazole （Group C）, and infected rats received 20mg/kg fluconazole with co-administration ofpantoprazole （Group D）. Microdialysis probes were implanted into the rats＇ striatum to continuously collect brain extracellular fluid （ECF） after the intravenous infusion of fluconazole with or without BCRP inhibitor pantoprazole. High-performance liquid chromatography （HPLC） was applied to measure the fluconazole concentrations in blood and brain ECF. The area under the concentration-time curves of fluconazole and the penetration of fluconazole passing though BBB were then calculated. Results Meningoencephalitis rat model was successfully established by intracerebral inoculation of Cr. neoforrnans. The infection significantly increased the penetration of fluconazole passing through BBB （P〈0.05）. Pantoprazole did not alter the distribution of fluconazole in normal rat＇s brain, but significantly increased the penetration of fluconazole passing through BBB of the infected rats （P〈0.05）. Conclusion Cr. neoformans infection can reduce the BBB resistance to fluconazole, and induce the efflux transport offluconazole from the brain ECF back into the blood by BCRP.