Insulin therapy restores impaired function and expression of P-glycoprotein in blood-brain barrier of experimental diabetes
Insulin therapy restores impaired function and expression of P-glycoprotein in blood-brain barrier of experimental diabetes
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DOI：
10.1016/j.bcp.2008.01.004
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发表时间：
2008-04-15
影响因子：
5.8
通讯作者：
Xie, Lin
中科院分区：
文献类型：
--
作者：
Liu, Haiyan;Liu, Xiaodong;Xie, Lin
目的探讨胰岛素对链脲佐菌素（STZ）诱导的糖尿病大鼠血脑屏障功能及P-糖蛋白（P-GP）表达的影响。以长春新碱（VCR）在大鼠体内的脑/血浆浓度比作为P-GP体内功能的指标。采用Western blot和定量真实的时间-聚合酶链反应（RT-PCR）分别检测大鼠大脑皮质P-GP蛋白水平及其mdr 1a/mdr 1b mRNA水平。采用罗丹明123（Rhodamine 123，Rho 123）摄取法和Western blot法观察胰岛素对原代培养的大鼠脑微血管内皮细胞（rBMEC）功能和P-GP表达的影响。结果表明，胰岛素治疗3周和5周后，糖尿病大鼠大脑皮质P-GP的外排功能、表达及mdr 1a/mdr 1b mRNA水平均明显改善。胰岛素治疗3周和5周后，正常大鼠大脑皮质P-GP水平和mdr 1a/mdr 1b mRNA水平均显著升高。在胰岛素缺乏的糖尿病大鼠血清中加入胰岛素使在糖尿病大鼠血清中培养的rBMEC中受损的功能和P-GP表达恢复正常。在含有不同胰岛素水平的正常培养液中，rBMEC表现出浓度依赖性的P-GP水平升高和Rho 123摄取降低。提示适当的胰岛素水平通过调节P-GP的功能和表达，对维持正常和糖尿病大鼠血脑屏障的正常功能起重要作用。(c)2008年爱思唯尔公司All rights reserved.
We aimed to investigate effects of insulin on function and expression of P-glycoprotein (P-GP) in the blood-brain barrier of streptozotocin (STZ)-induced diabetic rats. Brain-to-plasma concentration ratio of vincristine (VCR) in rats was used as an indicator of in vivo function of P-GP. Western blot and quantitative real time-polymerase chain reaction were used to determine protein levels of P-GP and its mdr1a/mdr1b mRNA levels, respectively, in cerebral cortex of rats. In vitro effects of insulin on function and expression of P-GP in primarily cultured rat brain microvessel endothelial cells (rBMECs) were evaluated using rhodamine 123 (Rho123) uptakes and Western blot, respectively. The results showed that 3- and 5-week insulin treatment alleviated the impaired efflux function, expression and mdr1a/mdr1b mRNA levels of P-GP in cerebral cortex of diabetic rats. The 3- and 5-week insulin treatments also significantly enhanced P-GP levels and mdr1a/mdr1b mRNA levels in the cerebral cortex of normal rats. Addition of insulin to the insulin-deficient diabetic rat serum normalized the impaired function and expression of P-GP in rBMECs cultured in diabetic rat serum. When incubated with normal culture medium containing different levels of insulin, the rBMECs exhibited the enhanced P-GP levels and the reduced Rho123 uptake in a concentration-dependent manner. So we may conclude that appropriate level of insulin plays an important role in maintaining the normal function of BBB through regulating the function and expression of P-GP in the diabetic and normal rats. (c) 2008 Elsevier Inc. All rights reserved.