中国血液净化

中国血液净化 ›› 2015, Vol. 14 ›› Issue (11): 676-680.doi: 10.3969/j.issn.1671-4091.2015.11.009

• 基础研究 • 上一篇    下一篇

脑型失衡综合症可能的分子基础：尿毒症小鼠脑组织水通道蛋白1,5及尿素转运蛋白B1表达的变化

史振伟,刘毅,刘伟,许焱,李晓璐,刘庆阳,王质刚   

  1. 煤炭总医院肾内科
  • 收稿日期:2015-05-19 修回日期:2015-09-15 出版日期:2015-11-12 发布日期:2015-11-12
  • 通讯作者: 刘庆阳 ：llqq2003yy@aliyun.com.cn E-mail:llqq2003yy@aliyun.com.cn

Expression changes of aquaporin 1, 5 and urea transporter B1 in brain tissues of uremic mice: the possible molecular basis for the brain-type dialysis disequilibrium syndrome in humans

  • Received:2015-05-19 Revised:2015-09-15 Online:2015-11-12 Published:2015-11-12

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摘要： 【摘要】目的探讨水通道蛋白1,5 及尿素转运蛋白B1 在慢性肾衰竭小鼠脑组织中表达水平的变化及影响，进一步揭示血液透析脑型失衡综合征可能的分子基础。方法选用6～8 周龄，雄性BALB/c 小鼠，将小鼠分为正常组(N)、假手术组(S)和慢性肾衰竭模型组(CRF 组)。CRF 模型小鼠通过对其右肾2/3肾皮质透热毁损，并在1 周后将左肾完全切除的方法建立。假手术组小鼠只进行麻醉和手术切口，肾脏不做处理。正常组的小鼠不做任何处理。模型建立后10、40 和70 天3 个时间点每组各处死5 只小鼠，并留取小鼠的肾脏、血清和脑组织标本。检测三组小鼠肾组织病理、血清肌酐和尿素氮；用Western Blotting方法测定在造模后10 天、40 天和70 天3 组小鼠脑组织内水通道蛋白1,5(Aquaporin,AQP)及尿素转运蛋白B1(Urea Transportprotein,UT-B1)的表达。结果CRF 模型组在造模后10 天肾组织病理结果显示部分肾小囊扩张，球囊粘连，肾小管上皮细胞颗粒样变性。造模后40 天、70 天表现为部分肾小球增生硬化，部分肾小管萎缩。造模10,40,70,天CRF 模型组血清肌酐分别是(841.80±336.93)umol/L、(1885.17±689.49)umol/L、(1276.56±496.09)umol/L，与正常组和假手术组肌酐值相比均显著升高(10d：F=26.768，P=0.007；40d：F=34.928，P=0.004；70d：F=29.998，P=0.005)，提示慢性肾衰竭模型成功。Western Blotting 检测实验各组脑组织AQP1、AQP5 及UT-B1 的表达，结果显示：在造模10,40,70 天，CRF模型组UT-B1 均未表达，正常组及假手术组表达差别无统计学意义。在造模后10 天正常组AQP1 表达量与假手术组及CRF 组比较均有统计学差异(P＜0.05)。CRF 模型组较正常组AQP1 表达量升高46.67%(t=0.122,P=0.001)；AQP-5 表达量较正常组升高41.09%(t=0.012, P= 0.001)。在造模后40 天，假手术组与正常组AQP- 1,5 表达量无显著性差异；而CRF 模型组AQP- 1 表达量较正常组升高28.98% (t=4.926,P=0.001)，AQP-5 表达量较正常组升高20.83%(t=0.857,P=0.003)。在造模后70 天，假手术组与正常组AQP-1,5 表达量无显著性差异，而CRF 模型组AQP-1 表达量较正常组升高30.26%(t=8.471,P=0.001)；AQP-5 表达较正常组升高45.67%(t=3.352,P=0.001)。结论CRF 模型小鼠脑组织AQP1,5 的表达明显增加，同时伴有尿素转运蛋白B1 的不表达或表达明显下降，这一结果为揭示脑型失衡综合症提供了线索。脑组织尿素转运蛋白的低表达导致快速血液透析脑中尿素清除延迟，进而形成脑血尿素浓度梯度，驱动水分通过过多表达的水道蛋白进入脑组织，导致脑水肿。

关键词: 脑型失衡综合症, 尿素转运蛋白, 慢性肾功能衰竭, 水通道蛋白, 脑水肿

Abstract: Objectives To investigate the expression changes of aquaporin (AQP) 1, 5 and urea transporter B1 (UT-B1) in brain tissues of mice with chronic renal failure, which may be useful to explain the molecular basis of brain- type dialysis disequilibrium syndrome in humans. Methods We randomly divided BALB/c mice into 3 groups: normal group, sham operation group, and chronic renal failure group after diathermy of the 2/3 right kidney cortex and then nephrectomy of the left kidney. Five mice in each group were sacrificed at 10 days, 40 days and 70 days after operation. Renal pathology, serum creatinine and blood urea nitrogen were examined. AQP and UT-B1 expressions in brain were assayed by western blotting. Results In chronic renal failure group at 40, 70 days after operation, renal pathological examination showed glomerular proliferation and sclerosis, kidney tubule atrophy and fibrosis. In chronic renal failure group at 10, 40, 70 days after operation, serum creatinine was 841.80±336.93 μmol/L, 1885.17±689.49 μmol/L, and 1276.56±496.09 μmol/L, respectively, significantly higher than that in normal group and that in sham group at 10 days (F= 26.768, P=0.007), 40 days (F=34.928, P=0.004) and 70 days (F=29.998, P=0.005) after operation. In chronic renal failure group, brain AQP1 expression increased by 46.67% (1.10±0.05 vs. 0.75±0.05, t =0.122, P=0.001) at 10 days after operation, by 28.98% (0.89±0.02 vs. 0.69±0.04, t=4.926, P=0.001) at 40 days after operation, and by 30.26% (0.99±0.07 vs. 0.76±0.05, t= 8.471, P=0.001) at 70 days after operation, as compared with that in control group; brain AQP5 expression increased by 41.09% (1.03±0.03 vs. 0.73±0.02, t=0.012, P=0.001) at 10 days after operation, by 20.83% (0.87±0.03 vs. 0.72±0.04, t= 0.857, P=0.003) at 40 days after operation, and by 45.67% (1.18±0.09 vs. 0.81±0.04, t =3.352, P=0.001) at 70 days after operation, as compared with that in control group; brain UT-B1 expression reduced significantly as compared with that in normal group and in sham operation group at 10 days, 40 days and 70 days after operation. Conclusions The increase of AQP1, 5 expressions and decrease of UT-B1 expression in brain of chronic renal failure mice may suggest the molecular basis of brain-type dialysis disequilibrium syndrome in humans. During rapid hemodialysis, delayed urea clearance happened due to the low expression of UT-B1, resulting in a concentration gradient of urea between brain and blood which drives water into brain by the over-expressed aquaporins and brain edema.

Key words: Brain-Type dialysis disequilibrium syndrome, Urea transport- protein, Chronic Renal Failure, Aquaporin, BrainEdema