Difference of lipid-lowering efficacy of "Xinjianqu" before and after fermentation and its mechanism based on LKB1-AMPK pathway and 16S rDNA sequencing technology / 中国中药杂志

On the basis of establishing the prescription of Xinjianqu and clarifying the increase of the lipid-lowering active ingredients of Xinjianqu by fermentation, this paper further compared the differences in the lipid-lowering effects of Xinjianqu before and after fermentation, and studied the mechanism of Xinjianqu in the treatment of hyperlipidemia. Seventy SD rats were randomly divided into seven groups, including normal group, model group, positive drug simvastatin group(0.02 g·kg~(-1)), and low-dose and high-dose Xinjianqu groups before and after fermentation(1.6 g·kg~(-1) and 8 g·kg~(-1)), with ten rats in each group. Rats in each group were given high-fat diet continuously for six weeks to establish the model of hyperlipidemia(HLP). After successful modeling, the rats were given high-fat diet and gavaged by the corresponding drugs for six weeks, once a day, to compare the effects of Xinjianqu on the body mass, liver coefficient, and small intestine propulsion rate of rats with HLP before and after fermentation. The effects of Xinjianqu before and after fermentation on total cholesterol(TC), triacylglyceride(TG), high-density lipoprotein cholesterol(HDL-C), low-density lipoprotein cholesterol(LDL-C), alanine aminotransferase(ALT), aspartate aminotransferase(AST), blood urea nitrogen(BUN), creatinine(Cr), motilin(MTL), gastrin(GAS), and the Na~+-K~+-ATPase levels were determined by enzyme-linked immunosorbent assay(ELISA). The effects of Xinjianqu on liver morphology of rats with HLP were investigated by hematoxylin-eosin(HE) staining and oil red O fat staining. The effects of Xinjianqu on the protein expression of adenosine 5'-monophosphate(AMP)-activated protein kinase(AMPK), phosphorylated AMPK(p-AMPK), liver kinase B1(LKB1), and 3-hydroxy-3-methylglutarate monoacyl coenzyme A reductase(HMGCR) in liver tissues were investigated by immunohistochemistry. The effects of Xinjianqu on the regulation of intestinal flora structure of rats with HLP were studied based on 16S rDNA high-throughput sequencing technology. The results showed that compared with those in the normal group, rats in the model group had significantly higher body mass and liver coefficient(P<0.01), significantly lower small intestine propulsion rate(P<0.01), significantly higher serum levels of TC, TG, LDL-C, ALT, AST, BUN, Cr, and AQP2(P<0.01), and significantly lower serum levels of HDL-C, MTL, GAS, Na~+-K~+-ATP levels(P<0.01). The protein expression of AMPK, p-AMPK, and LKB1 in the livers of rats in the model group was significantly decreased(P<0.01), and that of HMGCR was significantly increased(P<0.01). In addition, the observed＿otus, Shannon, and Chao1 indices were significantly decreased(P<0.05 or P<0.01) in rat fecal flora in the model group. Besides, in the model group, the relative abundance of Firmicutes was reduced, while that of Verrucomicrobia and Proteobacteria was increased, and the relative abundance of beneficial genera such as Ligilactobacillus and Lachnospiraceae＿NK4A136＿group was reduced. Compared with the model group, all Xinjianqu groups regulated the body mass, liver coefficient, and small intestine index of rats with HLP(P<0.05 or P<0.01), reduced the serum levels of TC, TG, LDL-C, ALT, AST, BUN, Cr, and AQP2, increased the serum levels of HDL-C, MTL, GAS, and Na~+-K~+-ATP, improved the liver morphology, and increased the protein expression gray value of AMPK, p-AMPK, and LKB1 in the liver of rats with HLP and decreased that of LKB1. Xinjianqu groups could regulate the intestinal flora structure of rats with HLP, increased observed＿otus, Shannon, Chao1 indices, and increased the relative abundance of Firmicutes, Ligilactobacillus(genus), Lachnospiraceae＿NK4A136＿group(genus). Besides, the high-dose Xinjianqu-fermented group had significant effects on body mass, liver coefficient, small intestine propulsion rate, and serum index levels of rats with HLP(P<0.01), and the effects were better than those of Xinjianqu groups before fermentation. The above results show that Xinjianqu can improve the blood lipid level, liver and kidney function, and gastrointestinal motility of rats with HLP, and the improvement effect of Xinjianqu on hyperlipidemia is significantly enhanced by fermentation. The mechanism may be related to AMPK, p-AMPK, LKB1, and HMGCR protein in the LKB1-AMPK pathway and the regulation of intestinal flora structure.

Role of prostaglandin E2 in the modulation of renal water transport / 生理学报

Prostaglandin E2 (PGE2), a bioactive lipid mediator, is one of the most important locally acting factors involved in a variety of physiological and pathophysiological processes. PGE2 binds with four EP receptors (EP1-4) to activate G protein-coupled receptor signaling responses. Recent functional and molecular studies have revealed that PGE2 plays an essential role in regulation of renal fluid transport via a variety of mechanisms. The water balance mainly depends on the regulation of aquaporin-2 (AQP2) by arginine vasopressin (AVP) in renal collecting duct principal cells. In recent years, increasing evidence suggests that PGE2 plays an important role in renal water reabsorption in the collecting ducts. In this paper, we reviewed the role of PGE2 and its receptors in the regulation of water reabsorption in the kidney, which may provide a new therapeutic strategy for many diseases especially nephrogenic diabetes insipidus.

Clinical characteristics and molecular genetics of seven neonates with congenital nephrogenic diabetes insipidus / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical characteristics, genetic basis and clinical treatment of seven neonates with congenital nephrogenic diabetes insipidus (NDI).@*METHODS@#Clinical data of the patients were collected. High-throughput sequencing was carried out to detect potential variants. Sanger sequencing was used to verify the results.@*RESULTS@#The patients were all males, with the age of onset being 10 to 21 days. All patients were admitted to the hospital for intermittent fever as the first symptom during the neonatal period. Additional symptoms had included polydipsia and polyuria. After the treatment, 5 patients had recovered, the remainders still had NDI symptoms and developmental retardation. Five children were found to harbor pathogenic variants of the AVPR2/AQP2 gene, which included one in-frame mutation of c.645_646insGCACCTACCCTGGGTATCGCC, two missense mutations of c.541C>T and c.419C>A, and two hemizygous deletions of the AVPR2/AQP2 gene. Among these, two were unreported previously. Cases 6 and 7 were a pair of twins. Both had carried homozygous missense variants of c.538G>A of the AVPR2/AQP2 gene, which was known to be pathogenic.@*CONCLUSION@#AVPR2/AQP2 is the main pathogenic gene for congenital NDI, for which two novel pathogenic variants have been discovered in this study. Above results have provided a basis for clinical diagnosis and genetic counseling for the affected pedigrees.

Dryness comparison of different fractions of Aurantii Fructus extract on normal mice and gastrointestinal motility disorder rats and spectrum-dryness study / 中国中药杂志

Aurantii Fructus is a commonly used qi-regulating medicinal herb in China. Both traditional Chinese medicine theory and modern experimental research demonstrate that Aurantii Fructus has dryness effect, the material basis of which remains unclear. In recent years, spectrum-effect relationship has been widely employed in the study of active ingredients in Chinese medicinal herbs, the research ideas and methods of which have been constantly improved. Based on the idea of spectrum-effect study, the ultra-high perfor-mance liquid chromatography-quadrupole-time of flight mass spectrometry(UHPLC-Q-TOF-MS) fingerprints of different fractions of Aurantii Fructus extract were established for the identification of total components. Then, the dryness effects of the fractions on normal mice and gastrointestinal motility disorder(GMD) rats were systematically compared. Finally, principal component analysis(PCA), Pearson bivariate correlation analysis and orthogonal partial least squares analysis(OPLS) were integrated to identify the dryness components of Aurantii Fructusextract. The results showed that narirutin, naringin, naringenin, poncirin, oxypeucedanin, and eriodictyol-7-O-glucoside had significant correlations with and contributed to the expression of AQP2 in kidney, AQP3 in colon, and AQP5 in submandibular gland, which were the main dryness components in Aurantii Fructus.

Expression of V2R and AQPs in the renal medulla of high-fat nutritional obesity of rat / Expresión de V2R y AQPs en la médula renal de ratas con obesidad nutricional alta en grasas

Recent evidence has indicated that adipose tissue produces bioactive substances that contribute to obesity-related kidney disease, altering the renal function and structure. Eight of the AQPs are expressed in the kidney, where several of them contribute to water absorption and maintenance of body water balance. In the study, we mainly examined the localization of AQP2, AQP3 and V2R in renal medulla of Normal Diet (ND) and High-fat Diet (HFD) of rats, respectively. In renal medulla of HFD, immunolight microscopy revealed weak expression of AQP2 at the apical plasma membrane and intracellular vesicles of principal cells of the IMCD and OMCD. AQP3 and V2R expression also observed a decrease in immunolabelling in the IMCD and OMCD. It was suggested that excess lipid accumulation may lead to lipotoxicity and may be the major driver of organ dysfunction such as water reabsorption dysfunction, which may be resulted from abnormal response of rphan G-protein-coupled receptors in kidney.

La evidencia reciente ha indicado que el tejido adiposo produce sustancias bioactivas que contribuyen a la enfermedad renal relacionada con la obesidad, alterando la función y la estructura renal. Ocho de los AQP se expresan en el riñón, donde varios de ellos contribuyen a la absorción de agua y al mantenimiento del equilibrio hídrico corporal. En el estudio, examinamos principalmente la localización de AQP2, AQP3 y V2R en la médula renal de ratas con dieta normal (ND) y ratas con dieta alta en grasas (HFD). En la médula renal del grupo HFD, la microscopía electrónica de barrido reveló una expresión débil de AQP2 en la membrana plasmática apical y las vesículas intracelulares de las células principales de IMCD y OMCD. La expresión de AQP3 y V2R también observó una disminución en el inmunomarcador en IMCD y OMCD. Se sugiere que el exceso de acumulación de lípidos puede conducir a lipotoxicidad y ser el principal impulsor de la disfunción orgánica, como la disfunción de reabsorción de agua, que puede ser el resultado de la respuesta anormal de los receptores acoplados a proteína rphan G en el riñón.

Immunohistochemical study of aquaporin 1 and 2 in the hepatobiliary system of Qinghai lizard (Pphrynocephalus vlangalii ) / Estudio inmunohistoquímico de aquaporin 1 y 2 en la sistema hepatobiliar del lagarto de Qinghai ( Phrynocephalus vlangalii )

A serous membrane covering the liver and the hepatic parenchyma, consists of hepatocytes, arteries, veins, hepatic sinusoids and biliary ductuli. There are erythrocytes, thrombocytes, melanin particles and Kupffer cell in the hepatic sinusoids and the blood vessels. The gall bladder wall consists of a mucous layer a muscle layer and a serous layer. The bottom of the epithelium abounds with round or oval secretory. In liver, immunohistochemistry results show that AQP1 have intense reaction in hepatic lobule, Kupffer cells (Macrophagocytus stellatus), hepatocytes, portal tract, blood islands, vein and artery, but almost no reaction of AQP2 was detected. In gallbladder, mucous epithelium, endothelial cells from vein and artery all have strong AQP1 expression, AQP2 showed minor diffused positive reaction in gallbladder, which suggesting that AQP1 may have the main role in the absorption and transportation of fluid in hepatobiliary system of Qinghai Lizard.

Una membrana serosa cubre el hígado y el parénquima hepático el cual está formado por hepatocitos, arterias, venas, sinusoides hepáticos y conductos biliares. Se encuentran eritrocitos, trombocitos, partículas de melanina y células de Kupffer en los sinusoides hepáticos y en los vasos sanguíneos. La pared de la vesícula biliar presenta tres capas: mucosa, muscular y serosa. En el hígado, la inmunohistoquímica mostró que AQP1 tiene una reacción intensa en el lóbulo hepático, células de Kupffer, hepatocitos, tracto portal e islotes sanguíneos. En venas y arterias, no se detectó reacción alguna de AQP2. En la vesícula biliar, el epitelio mucoso, las células endoteliales venosas y arteriales tuvieron una importante expresión de AQP1, sin embargo, AQP2 mostró una reacción positiva difusa menor, lo que sugiere que la AQP1 podría tener una función principal en la absorción y transporte de líquido en el sistema hepatobiliar del Lagarto Qinghai.

New insights into the transcriptional regulation of aquaporin-2 and the treatment of X-linked hereditary nephrogenic diabetes insipidus

The kidney collecting duct (CD) is a tubular segment of the kidney where the osmolality and final flow rate of urine are established, enabling urine concentration and body water homeostasis. Water reabsorption in the CD depends on the action of arginine vasopressin (AVP) and a transepithelial osmotic gradient between the luminal fluid and surrounding interstitium. AVP induces transcellular water reabsorption across CD principal cells through associated signaling pathways after binding to arginine vasopressin receptor 2 (AVPR2). This signaling cascade regulates the water channel protein aquaporin-2 (AQP2). AQP2 is exclusively localized in kidney connecting tubules and CDs. Specifically, AVP stimulates the intracellular translocation of AQP2-containing vesicles to the apical plasma membrane, increasing the osmotic water permeability of CD cells. Moreover, AVP induces transcription of the Aqp2 gene, increasing AQP2 protein abundance. This review provides new insights into the transcriptional regulation of the Aqp2 gene in the kidney CD with an overview of AVP and AQP2. It summarizes current therapeutic approaches for X-linked nephrogenic diabetes insipidus caused by AVPR2 gene mutations.

Notch signaling in the collecting duct regulates renal tubulointerstitial fibrosis induced by unilateral ureteral obstruction in mice

BACKGROUND/AIMS: Mind bomb-1 (Mib1) encodes an E3 ubiquitin ligase, which is required for the initiation of Notch signaling. Recently, it was demonstrated that the renal collecting duct plays an important role in renal fibrosis. Here, we investigated the role of Notch signaling in renal fibrosis using conditional knockout mice with the specific ablation of Mib1 in renal collecting duct principal cells. METHODS: Mib1-floxed mice (Mib1f/f ) were crossed with aquaporin 2 (AQP2)-Cre mice in order to generate principal cell-specific Mib1 knockout mice (Mib1f/f :AQP2-Cre+). Unilateral ureteral obstruction (UUO) was performed, and mice were sacrificed 7 days after UUO. RESULTS: After performing the UUO, renal tubulointerstitial fibrosis and the expression of transforming growth factor β were markedly enhanced in the obstructed kidneys of Mib1f/f mice compared with the sham-operated kidney of Mib1f/f mice. These changes were shown to be even more pronounced in the obstructed kidneys of Mib1f/f :AQP2-Cre+ mice than in those of the Mib1f/f mice . Furthermore, the number of TUNNEL-positive cells in renal collecting duct was higher in the obstructed kidneys of Mib1f/f :AQP2-Cre+ mice than in the kidneys of Mib1f/f mice. CONCLUSIONS: Notch signaling in the renal collecting duct plays an important role in the regulation of renal tubulointerstitial fibrosis and apoptosis after UUO.

Effect of Zhenwu Tang on regulating of "AVP-V2R-AQP2" pathway in NRK-52E cells / 中国中药杂志

This study was aimed to investigate the effect and mechanism of Zhenwu Tang on AVP-V2R-AQP2 pathway in NRK-52E cells . Forty eight male SD rats were randomly divided into eight groups with 6 animals in each group. Distilled water or 22.68 g·kg⁻¹·d⁻¹ Zhenwu Tang(calculated by raw drug dosage meter) was given by gavage. Blood samples were collected by cardiac puncture， and the medicated serum was centrifuged from the blood by 3 000 r·min⁻¹. NRK-52E cells were treated with different medicated serum or dDAVP. The condition of cell proliferation was detected by RTCA. The distribution of V2R and AQP2 in cells were detected by immunofluorescence. The expression of V2R， PKA and AQP2 were detected by Western blot and AQP2 mRNA level was detected by real-time PCR. Results showed that the level of AQP2 mRNA(<0.01) and protein expression of V2R， PKA and AQP2(<0.05， <0.01， <0.05) of Z7d group which was treated with Zhenwu Tang medicated serum for 24 h were significantly higher than that of normal rat serum group. And the expression level of V2R， p-AQP2 and AQP2(<0.01， <0.05， <0.01) of Z7d+dDAVP group were significantly increased comparing to normal rat serum group. The results indicate that the applying of Zhenwu Tang medicated serum could increase the expression level of V2R， PKA and AQP2 which exist in AVP-V2R-AQP2 pathway in NRK-52E， and there is synergistic effect between Zhenwu Tang medicated serum and dDAVP. So the pathway of AVP-V2R-AQP2 may be one of the mechanism for which Zhenwu Tang regulate balance of water transportation.

A Non-woven Path: Electrospun Poly(lactic acid) Scaffolds for Kidney Tissue Engineering

Chronic kidney disease is a major global health problem affecting millions of people; kidney tissue engineering provides an opportunity to better understand this disease, and has the capacity to provide a cure. Two-dimensional cell culture and decellularised tissue have been the main focus of this research thus far, but despite promising results these methods are not without their shortcomings. Polymer fabrication techniques such as electrospinning have the potential to provide a non-woven path for kidney tissue engineering. In this experiment we isolated rat primary kidney cells which were seeded on electrospun poly(lactic acid) scaffolds. Our results showed that the scaffolds were capable of sustaining a multipopulation of kidney cells, determined by the presence of: aquaporin-1 (proximal tubules), aquaporin-2 (collecting ducts), synaptopodin (glomerular epithelia) and von Willebrand factor (glomerular endothelia cells), viability of cells appeared to be unaffected by fibre diameter. The ability of electrospun polymer scaffold to act as a conveyor for kidney cells makes them an ideal candidate within kidney tissue engineering; the non-woven path provides benefits over decellularised tissue by offering a high morphological control as well as providing superior mechanical properties with degradation over a tuneable time frame.

Immunohistochemical study of aquaporin 1 and 2 in the reproductive tract of the bactrian camel (Camelus bactrianus) / Estudio inmunohistoquímico de acuaporina 1 y 2 en el tracto reproductivo del camello bactriano (Camelus bactrianus)

Spermatogenesis is associated with considerable fluid secretion or absorption in the male reproductive tract. Aquaporins (AQPs) are membrane protein channels that allow the rapid movement of water through epithelium. In the present study, immunohistochemistry was utilized to localize the expression of AQP 1, AQP2 in the testis and prostate of adult bactrian camel (Camelus bactrianus). Results show that AQP1 have intense reaction in rete testis, efferent ducts, vessels, seminiferous duct and in the prostate, AQP2 was found minor expression in the rete testis, vessels and prostate, which suggesting that AQP1 may have the main role in the absorption of the large amount of testicular fluid in male camel reproductive tract. Investigations of AQPs biology in camel could be relevant with technologies for assisted procreation in animal husbandry and aquaculture.

La espermatogénesis se asocia con la secreción de una cantidad considerable de líquido o absorción en el tracto reproductor masculino. Las acuaporinas (ACPs) son canales de proteínas de membrana que permiten el movimiento rápido de agua a través del epitelio. En el presente estudio, se utilizó inmunohistoquímica para localizar la expresión de ACP 1, ACP2 en el testículo y la próstata del camello bactriano adulto (Camelus bactrianus). Los resultados muestran que ACP1 tiene una reacción intensa en la rete testis, conductos eferentes, vasos, conductos seminíferos y en la próstata. La expresión ACP2, de menor importancia, se observó en la rete testis, vasos y próstata, lo que sugiere que ACP1 puede tener el papel principal en la absorción de gran cantidad de líquido testicular en el tracto reproductivo masculino del camello. Las investigaciones de la biología del ACP en camello podrían ser relevantes para las tecnologías de reproducción asistida de la ganadería y la acuicultura.

Altered Nitric Oxide System in Cardiovascular and Renal Diseases / 전남의대학술지

Nitric oxide (NO) is synthesized by a family of NO synthases (NOS), including neuronal, inducible, and endothelial NOS (n/i/eNOS). NO-mediated effects can be beneficial or harmful depending on the specific risk factors affecting the disease. In hypertension, the vascular relaxation response to acetylcholine is blunted, and that to direct NO donors is maintained. A reduction in the activity of eNOS is mainly responsible for the elevation of blood pressure, and an abnormal expression of iNOS is likely to be related to the progression of vascular dysfunction. While eNOS/nNOS-derived NO is protective against the development of atherosclerosis, iNOS-derived NO may be proatherogenic. eNOS-derived NO may prevent the progression of myocardial infarction. Myocardial ischemia/reperfusion injury is significantly enhanced in eNOS-deficient animals. An important component of heart failure is the loss of coronary vascular eNOS activity. A pressure-overload may cause severer left ventricular hypertrophy and dysfunction in eNOS null mice than in wild-type mice. iNOS-derived NO has detrimental effects on the myocardium. NO plays an important role in regulating the angiogenesis and slowing the interstitial fibrosis of the obstructed kidney. In unilateral ureteral obstruction, the expression of eNOS was decreased in the affected kidney. In triply n/i/eNOS null mice, nephrogenic diabetes insipidus developed along with reduced aquaporin-2 abundance. In chronic kidney disease model of subtotal-nephrectomized rats, treatment with NOS inhibitors decreased systemic NO production and induced left ventricular systolic dysfunction (renocardiac syndrome).

Effect of Diet and Water Intake on Aquaporin 2 Function

Appropriate control of diet and water intake is important for maintaining normal blood pressure, fluid and electrolyte homeostasis in the body. It is relatively understood that the amount of sodium and potassium intake directly affects blood pressure and regulates ion transporters; Na and K channel functions in the kidney. However, little is known about whether diet and water intake regulates Aquaporin (AQP) function. AQPs, a family of aquaporin proteins with different types being expressed in different tissues, are important for water absorption by the cell. Water reabsorption is a passive process driven by osmotic gradient and water permeability is critical for this process. In most of the nephron, however, water reabsorption is unregulated and coupled to solute reabsorption, such as AQP1 mediated water absorption in the proximal tubule. AQP2 is the only water channel founded so far that can be regulated by hormones in the kidney. AQP2 expressed in the apical membrane of the principal cells in the collecting tubule can be regulated by vasopressin (antidiuretic hormone) controlling the final volume of urine excretion. When vasopressin binds to its receptor on the collecting duct cells, it stimulates the translocation of AQP2 to the membrane, leading to increased water absorption via this AQP2 water channel. However, some studies also indicated that the AQP2 is also been regulated by vasopressin independent mechanism. This review is focused on the regulation of AQP2 by diet and the amount of water intake on salt and water homeostasis.

Altered Nitric Oxide System in Cardiovascular and Renal Diseases / 전남의대학술지

Nitric oxide (NO) is synthesized by a family of NO synthases (NOS), including neuronal, inducible, and endothelial NOS (n/i/eNOS). NO-mediated effects can be beneficial or harmful depending on the specific risk factors affecting the disease. In hypertension, the vascular relaxation response to acetylcholine is blunted, and that to direct NO donors is maintained. A reduction in the activity of eNOS is mainly responsible for the elevation of blood pressure, and an abnormal expression of iNOS is likely to be related to the progression of vascular dysfunction. While eNOS/nNOS-derived NO is protective against the development of atherosclerosis, iNOS-derived NO may be proatherogenic. eNOS-derived NO may prevent the progression of myocardial infarction. Myocardial ischemia/reperfusion injury is significantly enhanced in eNOS-deficient animals. An important component of heart failure is the loss of coronary vascular eNOS activity. A pressure-overload may cause severer left ventricular hypertrophy and dysfunction in eNOS null mice than in wild-type mice. iNOS-derived NO has detrimental effects on the myocardium. NO plays an important role in regulating the angiogenesis and slowing the interstitial fibrosis of the obstructed kidney. In unilateral ureteral obstruction, the expression of eNOS was decreased in the affected kidney. In triply n/i/eNOS null mice, nephrogenic diabetes insipidus developed along with reduced aquaporin-2 abundance. In chronic kidney disease model of subtotal-nephrectomized rats, treatment with NOS inhibitors decreased systemic NO production and induced left ventricular systolic dysfunction (renocardiac syndrome).

Effect of Yixintai Granule on mRNA and protein expression levels of AQP, in renal medulla of chronic heart failure rabbits / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To explore the effect of Yixintai Granule (YG) on mRNA and protein expression levels of AQP2 in renal medulla of chronic heart failure (CHF) rabbits.</p><p><b>METHODS</b>CHF rat model was established by ear marginal vein injection of adriamycin. Successfully modeled rabbits were divided into the model group, the high (8.4 g/kg), middle (4.2 g/kg), and low dose (2.1 g/kg) YG group, and the Furosemide group (2 mg/kg). Besides, a normal control group was set up. Equal volume of physiological saline was administered to rabbits of the model group and the normal control group by gastrogavage. YG at different doses was administered to rabbits of the 3 YG groups by gastrogavage. The intervention lasted for 4 weeks, once per day. After treatment the urine volume and pathomorphological changes of renal medulla tissue were observed. mRNA and its protein expression levels of AQP2 were detected.</p><p><b>RESULTS</b>Compared with the normal control group, the urine volume decreased significantly, mRNA and protein expression levels of renal medulla AQP2 increased significantly in the model group (all P < 0.01). Compared with the model group, the urine volume increased significantly, and mRNA and protein expression levels of renal medulla AQP2 decreased significantly in all medicated groups (all P < 0.01). Compared with the low dose YG group, the urine volume significantly increased and the mRNA expression level of renal medulla AQP2 significantly decreased in the middle and high dose YG groups (all P < 0.01). The expression level of AQP2 protein significantly decreased in the high dose YG group (P < 0.01). Pathological changes of the renal medulla was the most obviously seen in the model group. But they were alleviated to various degrees in all medicated groups. They were more obviously attenuated in the middle and high dose YG groups.</p><p><b>CONCLUSION</b>YG could improve CHF possibly through down-regulating mRNA and protein expression levels of AQP2 in renal medulla, and elevating the urine volume.</p>

A Minireview on Vasopressin-regulated Aquaporin-2 in Kidney Collecting Duct Cells

The kidney collecting duct is an important renal tubular segment for the regulation of body water and salt homeostasis. Water reabsorption in the collecting duct cells is regulated by arginine vasopressin (AVP) via the vasopressin V2-receptor (V2R). AVP increases the osmotic water permeability of the collecting duct cells through aquaporin-2 (AQP2) and aquaporin-3 (AQP3). AVP induces the apical targeting of AQP2 and transcription of AQP2 gene in the kidney collecting duct principal cells. The signaling transduction pathways resulting in the AQP2 trafficking to the apical plasma membrane of the collecting duct principal cells, include AQP2 phosphorylation, RhoA phosphorylation, actin depolymerization and calcium mobilization, and the changes of AQP2 protein abundance in water balance disorders have been extensively studied. These studies elucidate the underlying cellular and molecular mechanisms of body water homeostasis and provide the basis for the treatment of body water balance disorders.

Relationship between regulation effect of salvia miltiorrhiza on AQP2 in kidney and promoting blood circulation and diuresis / 中国中药杂志

Partial nature of "promoting blood circulation and dieresis" of Salvia Miltiorrhizain was initially demonstrated by investigating the regulation effect of AQP2 expression in kidney of trauma blood stasis model rats with the Salvia Miltiorrhizain so as to provide guidance for its clinical deployment of administration. Random allocation was taken to averagely divide 30 SD rats into two groups: 10 rats in normal group and 20 rats in blood stasis syndrome group. Trauma blood stasis rat model was established by quantitatively beating. Then the rat model group was divided into model group and salvia group. After 7 days of treatment, the rat kidney AQP2 expression was detected, the content of urine AQP2 was compared and the damaged local muscle and kidney pathological changes were observed by immunohistochemical method and western blot method. Compared with that of the normal group, rats in model group had inflammatory cells infiltration, blood stasis and edema of the injured local muscles and up-regulated AQP2 expression, decreasing urinary output, and kidney tissues blood stasis and edema (P < 0.05). On the other hand, compared with that of the model group, those parameters of rats in salvia group were all decreasing except urine output (P < 0.05). Such result indicated that Salvia Miltiorrhiza can reduce trauma blood stasis rat content of urine AQP2 and down-regulated AQP2 expression in kidney tissue, so as to reduce the reabsorption of water by renal tubular and increase urine output. The promoting blood circulation effect of Salvia Miltiorrhizain can alleviate the degree of the damaged tissue edema and encourage urine drainage. This therapy is closely related to the effect of regulating AQP2 in kidney by salvia, so the purpose of this study by verifying "promoting blood circulation and diuresis" as the mechanism for the regulation effect of the salvia on AQP2 expression.

A case of primary aldosteronism combined with acquired nephrogenic diabetes insipidus

Aldosterone-producing adrenal adenoma can induce various clinical manifestations as a result of chronic exposure to aldosterone. We report a rare case of a 37-year-old man who complained of general weakness and polyuria. He was diagnosed with aldosterone-producing adrenal adenoma and nephrogenic diabetes insipidus. Aldosterone enhances the secretion of potassium in the collecting duct, which can lead to hypokalemia. By contrast, nephrogenic diabetes insipidus, which manifests as polyuria and polydipsia, can occur in several clinical conditions such as acquired tubular disease and those attributed to toxins and congenital causes. Among them, hypokalemia can also damage tubular structures in response to vasopressin. The patient's urine output was > 3 L/d and was diluted. Owing to the ineffectiveness of vasopressin, we eventually made a diagnosis of nephrogenic diabetes insipidus. Laparoscopic adrenalectomy and intraoperative kidney biopsy were subsequently performed. The pathologic finding of kidney biopsy revealed a decrease in aquaporin-2 on immunohistochemical stain.

Effects of perindopril on expression of kidney aquaporin-2 and urine aquaporin-2 excretion in chronic heart failure rats / 中华心血管病杂志

<p><b>OBJECTIVE</b>To determine the expression of kidney aquaporin-2 (AQP2) and urine AQP2 excretion in chronic heart failure (CHF) rats and investigate effects of perindopril on the expression and excretion of AQP2.</p><p><b>METHODS</b>Sixty rats were randomized into three groups: control group, CHF group, CHF + Perindopril group. According to left ventricular myocardial infarction size, CHF group and perindopril group were further divided into heart failure subgroup (LVMI ≥ 20%) and cardiac functional compensation subgroup (LVMI < 20%), respectively. Blood and urine samples were collected from the rats for measuring serum Na(+), urine volume and urine osmolality. The concentration of plasma arginine vasopressin (p-AVP) was detected by radioimmunoassay (RIA). Immunohistochemistry, semi-quantitative real time-polymerase chain reaction (RT-PCR) and Western blot were performed for measurement of kidney inner medullary AQP2. The concentration of Urine AQP2 was measured by indirect enzyme-linked immunosorbent assay (indirect ELISA).</p><p><b>RESULTS</b>Immunohistochemistry, RT-PCR, Western blot examinations revealed increased quantity of the inner kidney medullary AQP2 expression (0.2013 ± 0.0417), AQP2 mRNA (0.98 ± 0.33) and AQP2 protein expression (0.94 ± 0.21) in heart failure subgroup (n = 13) compared to control group (n = 20, 0.1518 ± 0.0214, 0.58 ± 0.51, 0.51 ± 0.46), which could be significantly by perindopril (n = 13, 0.0712 ± 0.0218, 0.76 ± 0.45, 0.82 ± 0.49, all P < 0.05 vs. heart failure subgroup). The concentration of plasma arginine AVP [(19.72 ± 3.91) ng/ml] and Urine AQP2 [(82.52 ± 11.77) ng/L] were significantly higher in heart failure subgroup than in control group [n = 20, (51.67 ± 12.58) ng/L, (6.94 ± 3.10) ng/ml] (P < 0.05), which were significantly reduced by perindopril [n = 13, (15.65 ± 4.10) ng/L, (71.65 ± 9.21) ng/ml].</p><p><b>CONCLUSION</b>Increased expression of the kidney inner medullary AQP2 and the excretion of urine AQP2 in chronic heart failure rats could be reduced by perindopril.</p>

Regulation of aquaporin-2 in the kidney : A molecular mechanism of body-water homeostasis

The kidneys play a key role in the homeostasis of body water and electrolyte balance. Aquaporin-2 (AQP2) is the vasopressin-regulated water-channel protein expressed at the connecting tubule and collecting duct, and plays a key role in urine concentration and body-water homeostasis through short-term and long-term regulation of collecting duct water permeability. The signaling transduction pathways resulting in the AQP2 trafficking to the apical plasma membrane of the collecting duct principal cells, including AQP2 phosphorylation, RhoA phosphorylation, actin depolymerization, and calciumm obilization, and the changes of AQP2 abundance in water-balance disorders have been extensively studied. Dysregulation of AQP2 has been shown to be importantly associated with a number of clinical conditions characterized by body-water balance disturbances, including hereditary nephrogenic diabetes insipidus (NDI), lithium-induced NDI, electrolytes disturbance, acute and chronic renal failure, ureteral obstruction, nephrotic syndrome, congestive heart failure, and hepatic cirrhosis. Recent studies exploiting omics technology further demonstrated the comprehensive vasopressin signaling pathways in the collecting ducts. Taken together, these studies elucidate the underlying molecular mechanisms of body-water homeostasis and provide the basis for the treatment of body-water balance disorders.