目的 研究維生素D缺乏和過剩對大鼠腦內P-糖蛋白（P-gp）和乳腺癌耐藥蛋白（BCRP）功能和表達的影響。方法 18只雄性SD大鼠隨機分為對照組、去維生素D（NVD）組和高維生素D（HVD）組，分別使用標準飼料（1 000 IU/kg維生素D）、去維生素D（0 IU/kg維生素D）飼料和高維生素D（20 000 IU/kg維生素D）飼料飼養(yǎng)12周，誘導維生素D缺乏和過剩模型，測定大鼠血清中25-羥基維生素D₃[25（OH） D₃]、1α，25二羥基維生素D₃[1α，25（OH）₂D₃]水平以確證模型。造模成功后，尾iv含羅丹明123（0.2 mg/kg）、哌唑嗪（1 mg/kg）和熒光素鈉（2 mg/kg）的混合探針，采用LC-FLU或LC-MS法分別測定大鼠腦皮層、海馬和血漿中羅丹明123、哌唑嗪和熒光素鈉的濃度，計算腦血比，評價P-gp、BCRP功能和血腦屏障完整性；采用Western blotting法測定大鼠腦皮層和海馬P-gp和BCRP的相對表達量。用25（OH） D₃、1α，25（OH）₂D₃分別溫孵人微血管內皮細胞（hCMEC/D3），以羅丹明123、哌唑嗪為探針評價細胞中P-gp和BCRP的功能。結果 維生素D缺乏大鼠腦內P-gp功能和表達下調，而維生素D過剩大鼠腦內P-gp功能和表達上調，維生素D缺乏和過剩均不影響大鼠腦內BCRP的功能和表達。25（OH） D₃不影響hCMEC/D3細胞P-gp和BCRP的功能，而1α，25（OH）₂D₃上調hCMEC/D3細胞中P-gp的功能。結論 維生素D缺乏導致的體內1α，25（OH）₂D₃水平降低可能是下調大鼠腦內P-gp的功能和表達的原因之一，而維生素D過剩導致的體內1α，25（OH）₂D₃水平升高可能是上調大鼠腦內P-gp的功能和表達的原因之一。

Objective To study the effect of vitamin D deficiency and excess on the function and expression of brain P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) in rats. Methods Eighteen male SD rats were randomly divided into control group, no vitamin D (NVD) group, and high vitamin D group (HVD). The rats were fed with standard diet (1 000 IU/kg vitamin D), no vitamin D diet (0 IU/kg vitamin D), and high vitamin D diet (20 000 IU/kg vitamin D) for 12 weeks, respectively. The serum concentrations of 25(OH)D₃ and 1α,25(OH)₂D₃ were determined to confirm the successful establishment of the rat model of vitamin D deficiency and vitamin D excess. A mixed probe containing rhodamine 123 (0.2 mg/kg), prazosin (1 mg/kg), and fluorescein sodium (2 mg/kg) was injected into the tail vein of the rats. The concentrations of rhodamine 123, prazosin, and fluorescein sodium in rat cerebral cortex, hippocampus, and plasma were measured. The ratios of brain probe concentration to plasma probe concentration were calculated to evaluate the function of P-gp, BCRP, and the integrity of blood brain barrier. The relative protein expression of P-gp and BCRP in cortex and hippocampus was also measured by Western blotting. hCMEC/D3 cells were used to document the effects of 25(OH)D₃ and 1α,25(OH)₂D₃ on the function on of P-gp and BCRP. Results Function and expression of P-gp in the brain of vitamin D deficient rats were down-regulated, while the function and expression of P-gp in the brain of vitamin D excess rats were up-regulated. Vitamin D deficiency and excess did not affect the function and expression of BCRP in the brain of rats. 25(OH)D₃ did not affect the function of P-gp and BCRP in hCMEC/D3 cells, while 1α,25(OH)₂D₃ up-regulated the function of P-gp in hCMEC/D3 cells.Conclusion The decreased levels of 1α,25(OH)₂D₃ caused by vitamin D deficiency may be one of the reasons for down-regulating the function and expression of brain P-gp in rats, while the increased levels of 1α,25(OH)₂D₃ caused by vitamin D excess may be one of the reasons for up-regulating the function and expression of brain P-gp in rats.

R965

江蘇省自然科學基金面上項目（BK20161368）