AIM： To quantify changes in urinary excretion of aquaporin2 water channels （u-AQP2）, the sodium-potassium-chloride co-transporter （u-NKCC2） and the epithelial sodium channels （u-ENaC） during treatment with bend...AIM： To quantify changes in urinary excretion of aquaporin2 water channels （u-AQP2）, the sodium-potassium-chloride co-transporter （u-NKCC2） and the epithelial sodium channels （u-ENaC） during treatment with bendrofumethiazide （BFTZ）, amiloride and placebo.METHODS： In a randomized, double-blinded, placebo-controlled, 3-way crossover study we examined 23 healthy subjects on a standardized diet and fuid intake. The subjects were treated with amiloride 5 mg, BFTZ 1.25 mg or placebo twice a day for 4.5 d before each examination day. On the examination day, glomerular filtration rate was measured by the constant infusion clearance technique with 51Cr-EDTA as reference substance. To estimate the changes in water transport via AQP2 and sodium transport via NKCC2 and ENaC, u-NKCC2, the gamma fraction of ENaC （u-ENaCγ）, and u-AQP2 were measured at baseline and after infusion with 3% hypertonic saline. U-NKCC2, u-ENaCγ, u-AQP2 and plasma concentrations of vasopressin （p-AVP）, renin （PRC）, angiotensin Ⅱ （p-ANG Ⅱ） and aldosterone （p-Aldo） were measured, by radioimmunoassay. Central blood pressure was estimated by applanation tonometry and body fuid volumes were estimated by bio-impedance spectroscopy. General linear model with repeated measures or related samples Friedman’s two-way analysis was used to compare differences. Post hoc Bonferroni correction was used for multiple comparisons of post infusion periods to baseline within each treatment group.RESULTS： At baseline there were no differences in u-NKCC2, u-ENaCγ and u-AQP2. PRC, p-Ang Ⅱ and p-Aldo were increased during active treatments （P 〈 0.001）. After hypertonic saline, u-NKCC2 increased during amiloride （6% ± 34%; P = 0.081） and increased significantly during placebo （17% ± 24%; P = 0.010）. U-AQP2 increased signifcantly during amiloride （31% ± 22%; P 〈 0.001） and placebo （34% ± 27%; P 〈 0.001）, while u-NKCC2 and u-AQP2 did not change signifcantly during BFTZ （-7% ± 28%; P = 0.257 and 5% ± 16%; P = 0.261）. U- ENaCγ increased in all three groups （ P 〈 0.050）. PRC, AngⅡ and p-Aldo decreased to the same extent, while AVP increased, but to a smaller degree during BFTZ （ P = 0.048）. cDBP decreased significantly during BFTZ （P 〈 0.001）, but not during amiloride or placebo. There were no significant differences in body fuid volumes.CONCLUSION： After hypertonic saline, u-NKCC2 and u-AQP2 increased during amiloride, but not during BFTZ. Lower p-AVP during BFTZ potentially caused less stimulation of NKCC2 and AQP2 and subsequent lower reabsorption of water and sodium.展开更多
BACKGROUND: Obstructive jaundice is a common disease. Acute renal injury, secondary to obstructive jaundice, is one of the main causes of postoperative multiple system failure. This investigation evaluated renal funct...BACKGROUND: Obstructive jaundice is a common disease. Acute renal injury, secondary to obstructive jaundice, is one of the main causes of postoperative multiple system failure. This investigation evaluated renal function and renal aquaporin 2 (AQP2) expression changes in obstructive jaundice. METHODS: Forty male Wistar rats were equally randomized into two groups. Twenty in the obstructive jaundice group were subjected to common bile duct ligation, and then were subdivided into 7- and 14-day obstruction groups, and the other 20 sham-operated rats were also subdivided into 7- and 14-day groups. At the end of each experiment, rats were sacrificed, venous blood was collected from the inferior vena cava, and serum creatinine and urine nitrogen concentrations were measured. At the same time, the medulla of the right kidney was separated and AQP2 expression was assessed. The RT-PCR technique was used to detect AQP2 mRNA expression. RESULTS: Ligation of the common bile duct caused significant rises in serum bilirubin, creatinine clearance and urine nitrogen. AQP2 expression in the medulla decreased mere significantly (38.35 +/- 2.08) in the 7-day ligation group than in the sham-operated group (41.06 +/- 1.04), as did that in the 14-day ligation group, even more than (31.89 +/- 1.57). The expression of AQP2 mRNA also decreased more significantly in the 14-day group (0.5429 +/- 0.1107) than in the 7-day group (0.6071 +/- 0.1328). CONCLUSION: AQP2 expression is inhibited in obstructive jaundice, and so is its gene expression.展开更多
Objective To investigate the role of extracellular signal-regulated kinase1/2（ERK1/2） pathway in the regulation of aquaporin 4（AQP4） expression in cultured astrocytes after scratch-injury. Methods The scratch-inju...Objective To investigate the role of extracellular signal-regulated kinase1/2（ERK1/2） pathway in the regulation of aquaporin 4（AQP4） expression in cultured astrocytes after scratch-injury. Methods The scratch-injury model was produced in cultured astrocytes of rat by a 10-μL plastic pipette tip. The morphological changes of astrocytes and lactate dehydrogenase（LDH） leakages were observed to assess the degree of scratch-injury. AQP4 expression was detected by immunofluorescence staining and Western blot, and phosphorylated-ERK1/2（p-ERK1/2） expression was determined by Western blot. To explore the effect of ERK1/2 pathway on AQP4 expression in scratch-injured astrocytes, 10 μmol/L U0126（ERK1/2 inhibitor） was incubated in the medium at 30 min before the scratch-injury in some groups. Results Increases in LDH leakage were observed at 1, 12, and 24 h after scratch-injury, and AQP4 expression was reduced simultaneously. Decrease in AQP4 expression was associated with a significant increase in ERK1/2 activation. Furthermore, pretreatment with U0126 blocked both ERK1/2 activation and decrease in AQP4 expression induced by scratch-injury. Conclusion These results indicate that ERK1/2 pathway down-regulates AQP4 expression in scratch-injured astrocytes, and ERK1/2 pathway might be a novel therapeutic target in reversing the effects of astrocytes that contribute to traumatic brain edema.展开更多
In current study, the effect of angiotensin receptor blocker Micardis on the localization and expression of aquaporin-2 （AQP2） was investigated in the renal medullary collecting duct of mice with diabetic nephropat...In current study, the effect of angiotensin receptor blocker Micardis on the localization and expression of aquaporin-2 （AQP2） was investigated in the renal medullary collecting duct of mice with diabetic nephropathy （DN）. Mice were divided into three groups： normal group, DN group and Micardis-treated group. Six weeks after establishment of STZ-induced DN model in mice, the expression of AQP2 in renal medulla was detected measured by semiquantitative immunofluorescence histochemistry and Western blot techniques, and the localization of AQP2 by confocal immunofluorescence laser scanning microscopy. The results showed that the urinary osmolality was decreased in DN group as compared with normal group （2.39±0.11 vs 3.16±0.16, P〈0.05）. Although the localization of AQP2 on the renal medulla was unchanged, the expression of AQP2 was increased significantly in DN group as compared with normal group. Micardis could partly attenuate above changes. It was concluded that treatment with Micardis could partly rectify the abnormal expression of AQP2 in renal medulla of DN mice, which suggested that rennin-angiotensin system （RAS） is implicated in the pathogenesis of DN by regulating the expression of AQP2.展开更多
In this study,the effects of hyperosmolality on the expression of urea transporter A2 (UTA2) and aquaporin 2 (AQP2) were investigated in transfected immortalized mouse medullary collecting duct (mIMCD3) cell line.AQP2...In this study,the effects of hyperosmolality on the expression of urea transporter A2 (UTA2) and aquaporin 2 (AQP2) were investigated in transfected immortalized mouse medullary collecting duct (mIMCD3) cell line.AQP2-GFP-pCMV6 and UTA2-GFP-pCMV6 plasmids were stably transfected into mIMCD3 cells respectively.Transfected mIMCD3 and control cells were cultured in different hy-pertonic media,which were made by NaCl alone,urea alone,or an equiosmolar mixture of NaCl and urea.The mRNA and protein expression of AQP2 was elevated by the stimulation of NaCl alone,urea alone and NaCl plus urea in AQP2-mIMCD3 cells;whereas NaCl alone and NaCl plus urea rather than urea alone increased the mRNA and protein expression of UTA2 in UTA2-mIMCD3 cells,and all the expression presented an osmolality-dependent manner.Moreover,the mRNA and protein expression of UTA2 rather than AQP2 was found to be synergistically up-regulated by a combination of NaCl and urea in mIMCD3 cells.It is concluded that NaCl and urea synergistically induce the expression of UTA2 rather than AQP2 in mIMCD3 cells,and hyperosmolality probably mediates the expression of AQP2 and UTA2 through different mechanisms.展开更多
基金Supported by Grants from The Lundbeck FoundationAase and Ejnar Danielsens Foundation+1 种基金Helen and Ejnar Bjoernows FoundationRegion Midjutlands Research Fund
文摘AIM： To quantify changes in urinary excretion of aquaporin2 water channels （u-AQP2）, the sodium-potassium-chloride co-transporter （u-NKCC2） and the epithelial sodium channels （u-ENaC） during treatment with bendrofumethiazide （BFTZ）, amiloride and placebo.METHODS： In a randomized, double-blinded, placebo-controlled, 3-way crossover study we examined 23 healthy subjects on a standardized diet and fuid intake. The subjects were treated with amiloride 5 mg, BFTZ 1.25 mg or placebo twice a day for 4.5 d before each examination day. On the examination day, glomerular filtration rate was measured by the constant infusion clearance technique with 51Cr-EDTA as reference substance. To estimate the changes in water transport via AQP2 and sodium transport via NKCC2 and ENaC, u-NKCC2, the gamma fraction of ENaC （u-ENaCγ）, and u-AQP2 were measured at baseline and after infusion with 3% hypertonic saline. U-NKCC2, u-ENaCγ, u-AQP2 and plasma concentrations of vasopressin （p-AVP）, renin （PRC）, angiotensin Ⅱ （p-ANG Ⅱ） and aldosterone （p-Aldo） were measured, by radioimmunoassay. Central blood pressure was estimated by applanation tonometry and body fuid volumes were estimated by bio-impedance spectroscopy. General linear model with repeated measures or related samples Friedman’s two-way analysis was used to compare differences. Post hoc Bonferroni correction was used for multiple comparisons of post infusion periods to baseline within each treatment group.RESULTS： At baseline there were no differences in u-NKCC2, u-ENaCγ and u-AQP2. PRC, p-Ang Ⅱ and p-Aldo were increased during active treatments （P 〈 0.001）. After hypertonic saline, u-NKCC2 increased during amiloride （6% ± 34%; P = 0.081） and increased significantly during placebo （17% ± 24%; P = 0.010）. U-AQP2 increased signifcantly during amiloride （31% ± 22%; P 〈 0.001） and placebo （34% ± 27%; P 〈 0.001）, while u-NKCC2 and u-AQP2 did not change signifcantly during BFTZ （-7% ± 28%; P = 0.257 and 5% ± 16%; P = 0.261）. U- ENaCγ increased in all three groups （ P 〈 0.050）. PRC, AngⅡ and p-Aldo decreased to the same extent, while AVP increased, but to a smaller degree during BFTZ （ P = 0.048）. cDBP decreased significantly during BFTZ （P 〈 0.001）, but not during amiloride or placebo. There were no significant differences in body fuid volumes.CONCLUSION： After hypertonic saline, u-NKCC2 and u-AQP2 increased during amiloride, but not during BFTZ. Lower p-AVP during BFTZ potentially caused less stimulation of NKCC2 and AQP2 and subsequent lower reabsorption of water and sodium.
基金This study was supported by a grant from the Liaoning Province Research Project for Institution of Higher Education (2004D282).
文摘BACKGROUND: Obstructive jaundice is a common disease. Acute renal injury, secondary to obstructive jaundice, is one of the main causes of postoperative multiple system failure. This investigation evaluated renal function and renal aquaporin 2 (AQP2) expression changes in obstructive jaundice. METHODS: Forty male Wistar rats were equally randomized into two groups. Twenty in the obstructive jaundice group were subjected to common bile duct ligation, and then were subdivided into 7- and 14-day obstruction groups, and the other 20 sham-operated rats were also subdivided into 7- and 14-day groups. At the end of each experiment, rats were sacrificed, venous blood was collected from the inferior vena cava, and serum creatinine and urine nitrogen concentrations were measured. At the same time, the medulla of the right kidney was separated and AQP2 expression was assessed. The RT-PCR technique was used to detect AQP2 mRNA expression. RESULTS: Ligation of the common bile duct caused significant rises in serum bilirubin, creatinine clearance and urine nitrogen. AQP2 expression in the medulla decreased mere significantly (38.35 +/- 2.08) in the 7-day ligation group than in the sham-operated group (41.06 +/- 1.04), as did that in the 14-day ligation group, even more than (31.89 +/- 1.57). The expression of AQP2 mRNA also decreased more significantly in the 14-day group (0.5429 +/- 0.1107) than in the 7-day group (0.6071 +/- 0.1328). CONCLUSION: AQP2 expression is inhibited in obstructive jaundice, and so is its gene expression.
基金supported by the National Natural Science Foundation of China,No.81271286 to YUAN Fang and No.81228009 to YANG Shao Hua
文摘Objective To investigate the role of extracellular signal-regulated kinase1/2（ERK1/2） pathway in the regulation of aquaporin 4（AQP4） expression in cultured astrocytes after scratch-injury. Methods The scratch-injury model was produced in cultured astrocytes of rat by a 10-μL plastic pipette tip. The morphological changes of astrocytes and lactate dehydrogenase（LDH） leakages were observed to assess the degree of scratch-injury. AQP4 expression was detected by immunofluorescence staining and Western blot, and phosphorylated-ERK1/2（p-ERK1/2） expression was determined by Western blot. To explore the effect of ERK1/2 pathway on AQP4 expression in scratch-injured astrocytes, 10 μmol/L U0126（ERK1/2 inhibitor） was incubated in the medium at 30 min before the scratch-injury in some groups. Results Increases in LDH leakage were observed at 1, 12, and 24 h after scratch-injury, and AQP4 expression was reduced simultaneously. Decrease in AQP4 expression was associated with a significant increase in ERK1/2 activation. Furthermore, pretreatment with U0126 blocked both ERK1/2 activation and decrease in AQP4 expression induced by scratch-injury. Conclusion These results indicate that ERK1/2 pathway down-regulates AQP4 expression in scratch-injured astrocytes, and ERK1/2 pathway might be a novel therapeutic target in reversing the effects of astrocytes that contribute to traumatic brain edema.
基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China (Grant No. 2007-1108)
文摘In current study, the effect of angiotensin receptor blocker Micardis on the localization and expression of aquaporin-2 （AQP2） was investigated in the renal medullary collecting duct of mice with diabetic nephropathy （DN）. Mice were divided into three groups： normal group, DN group and Micardis-treated group. Six weeks after establishment of STZ-induced DN model in mice, the expression of AQP2 in renal medulla was detected measured by semiquantitative immunofluorescence histochemistry and Western blot techniques, and the localization of AQP2 by confocal immunofluorescence laser scanning microscopy. The results showed that the urinary osmolality was decreased in DN group as compared with normal group （2.39±0.11 vs 3.16±0.16, P〈0.05）. Although the localization of AQP2 on the renal medulla was unchanged, the expression of AQP2 was increased significantly in DN group as compared with normal group. Micardis could partly attenuate above changes. It was concluded that treatment with Micardis could partly rectify the abnormal expression of AQP2 in renal medulla of DN mice, which suggested that rennin-angiotensin system （RAS） is implicated in the pathogenesis of DN by regulating the expression of AQP2.
基金supported by a grant from National Natural Science foundation of China (No. 30871173)
文摘In this study,the effects of hyperosmolality on the expression of urea transporter A2 (UTA2) and aquaporin 2 (AQP2) were investigated in transfected immortalized mouse medullary collecting duct (mIMCD3) cell line.AQP2-GFP-pCMV6 and UTA2-GFP-pCMV6 plasmids were stably transfected into mIMCD3 cells respectively.Transfected mIMCD3 and control cells were cultured in different hy-pertonic media,which were made by NaCl alone,urea alone,or an equiosmolar mixture of NaCl and urea.The mRNA and protein expression of AQP2 was elevated by the stimulation of NaCl alone,urea alone and NaCl plus urea in AQP2-mIMCD3 cells;whereas NaCl alone and NaCl plus urea rather than urea alone increased the mRNA and protein expression of UTA2 in UTA2-mIMCD3 cells,and all the expression presented an osmolality-dependent manner.Moreover,the mRNA and protein expression of UTA2 rather than AQP2 was found to be synergistically up-regulated by a combination of NaCl and urea in mIMCD3 cells.It is concluded that NaCl and urea synergistically induce the expression of UTA2 rather than AQP2 in mIMCD3 cells,and hyperosmolality probably mediates the expression of AQP2 and UTA2 through different mechanisms.
