OBJECTIVETo study the interaction among aquaporin1 (AQP), aquaporin2 (AQP2) and antisecretory factor( AF) , and their expression in the rat inner ear for furthur understanding of Meniere' s disease.

METHODSInner ear tissue section of six healthy male Sprague-Dawley rats was performed and Envision immunochemical staining was applied to detect the expression of AF, AQP1 and AQP2 in the rat inner ear. Vestibular and cochlear tissues of twenty healthy male Sprague-Dawley rats were dissected. Coimmunoprecipitation and Western Blot were used to specifically immunoprecipitate AF protein in the vestibular and cochlear tissues with monoclonal antibodies against AQP1 and polyclonal antibodies antibodies against AQP2 to detect the above precipitate with specific antibodies against AF.

RESULTS(1) AF was widely distributed in the inner ear, such as marginal cells of stria vascularis , five classes of spiral ligament fibrocyte , Reissner's membrane, basilar membrane, ampullar crest and so on with mild or moderate staining. In addition, round membrane was moderately or markedly stained. Positive immunostaining was found in the cochlear spiral ganglion, vestibular nerve and cochlear nerve. AQP1 was distributed in the intermediate cells in stria vascularis, type III fibrocyte of spiral ligament, basilar membrane and round membrane with moderate to marked degree of immunostaining intensity. AQP2 was mainly localized to the type II, IV, and V fibrocyte of spiral ligament, with moderate to marked degree of immunostaining intensity, round membrane was weakly stained. (2) No band was observed in the control and a single immunoreactive band of 60 000 was observed, which was equal to the molecular mass of AF.

CONCLUSIONS(1) AF, AQP1 and AQP2 have its individual specific localization in the rat inner ear, which was close to the parts of endolymph, so regulating water of the endolymph may be possible. (2) The range of localization of AF overlapped the distribution of AQP1 and AQP2. The results showed the existence of AF protein in the immunoprecipitate using co-immunoprecipitation combined with Western Blot. It suggested that the interaction between AQP1, AQP2 and AF might be possible.

Animals ; Aquaporin 1 ; metabolism ; Aquaporin 2 ; metabolism ; Cochlea ; metabolism ; Ear, Inner ; metabolism ; Male ; Neuropeptides ; metabolism ; Rats ; Rats, Sprague-Dawley

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.
Aquaporin 2/metabolism* ; Biological Transport ; Diabetes Insipidus, Nephrogenic ; Dinoprostone ; Humans ; Water/metabolism*

OBJECTIVETo study the estrogen-like action mechanism of Menoprogen on ovariectomized female rats.

METHODOvariectomized rat model (OVX) was established and estradiol (17beta-estradiol, E2) was used as positive control. The uterine coefficient and serum E2 level were determined after administration of Menoprogen for 2 weeks. The uterine vascular endothelial growth factor (VEGF), water channel protein (aquaporin, AQP), estrogen receptor (ER), progesterone receptor (PR) and the expression of proto-oncogenes (c-jun, c-fos) were observed by immunohistochemical method. Yeast two-hybrid assay was applied to detect the existence of components combining with ERalpha or ERbeta in Menoprogen.

RESULTBoth Menoprogen and E2 could significantly elevate the uterine coefficient of OVX rats, increase the level of serum E2 and up-regulate the expressions of VEGF, AQP2 as well as AQP5 in uterus. E2, not as E2 Menoprogen couldn't promote the expressions of ERalpha, PR, c-jun and c-fos in OVX rat uterus. And yeast two-hybrid assay showed no components combining with ERalpha or ERbeta in Menoprogen.

CONCLUSIONMenoprogen has estrogen-like effect, and can be used to treat menopause syndrome. The risk of estrogen-mediated endometrial cancer is low for this treatment because its mechanism is different from estrogen-like substances.

Animals ; Aquaporin 2 ; metabolism ; Aquaporin 5 ; metabolism ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; Estradiol ; blood ; Estrogen Receptor alpha ; metabolism ; Estrogens ; pharmacology ; Female ; Ovariectomy ; adverse effects ; Rats ; Rats, Wistar ; Receptors, Progesterone ; metabolism ; Vascular Endothelial Growth Factor A ; metabolism

OBJECTIVETo investigate the effect of rhubarb on expressions of aquaporin-2 and 4 (AQP2 and AQP4) in rat's kidney.

METHODSThirty-two SD rats were randomly divided into 4 groups, the normal control group, and the three rhubarb groups medicated via gastrogavage with low, mid and high dose of rhubarb extract (total anthraquinone) respectively. The 6 h and 24 h urine volume were measured, and the protein and mRNA expressions of AQP2 and AQP4 in renal tissue were determined with immunohistochemistry, Western blot and RT-PCR.

RESULTSNo significant difference between the control group and the low dose rhubarb treated group was found in urine volume, as well as in AQP2 and AQP4 protein and mRNA expressions. But the urine volume was obviously higher, the protein and mRNA expressions of AQP2 and AQP4 were markedly lower in rats after mid/high dose rhubarb medication respectively when compared with those in the normal controls (all P < 0.01).

CONCLUSIONRhubarb can inhibit the protein and mRNA expressions of AQP2 and AQP4 in rats' kidney, which probably is one of the mechanisms of rhubarb for diuresis.

Animals ; Aquaporin 2 ; genetics ; metabolism ; Aquaporin 4 ; genetics ; metabolism ; Drugs, Chinese Herbal ; administration & dosage ; Gene Expression ; drug effects ; Kidney ; drug effects ; metabolism ; Male ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Rheum ; chemistry

OBJECTIVETo investigate the effect and mechanism of emodin for regulating aquapoin-2 (AQP2) in NRK cells cultured in vitro.

METHODSExperiments on NRK cells cultured with alpha-DMEM medium in vitro were conducted in two steps. (1) Cells were randomly divided into 4 groups: the control group, and the three emodin treated groups treated with different dosages of emodin (5, 10 and 20 mg/L) respectively. After 24 h treatment, the location of AQP2 was decided by indirect immunofluorescene, and the AQP2 protein and mRNA expression levels were detected by Western blot and semiquantive RT-PCR. (2) Cells were randomly divided into 4 groups, the control group, and the three treated groups treated respectively with 10 mg/L 8-Bromo-cAMP, 20 mg/L emodin, and 20 mg/L emodin +10 mg/L 8-Bromo-cAMP. The activity of protein kinase A (PKA) in NRK cells after 24 h treatment was determined with non-radioactive detecting method.

RESULTSAQP2 was located at the cell membrane of NRK cells. Western blot and semiquantitive RT-PCR found that AQP2 protein and mRNA expressions were significantly decreased in NRK cells of groups treated by 10 mg/L and 20 mg/L emodin (P < 0.05). PKA activity determination showed significantly decreased phosphorylation level of PKA in NRK cells of groups treated with 20 mg/L emodin group (P < 0.05).

CONCLUSIONEmodin can inhibit the genetic transcription and the translation of AQP2 gene in NRK cells, which demonstrates that the change of AQP2 expression regulated by emodin may be correlated with the diuresis effect of rhubarb, and it is likely that the regulation is going through PKA signal pathway.

Animals ; Aquaporin 2 ; genetics ; metabolism ; Cell Line ; Cyclic AMP-Dependent Protein Kinases ; metabolism ; Emodin ; pharmacology ; Kidney ; cytology ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats ; Signal Transduction ; drug effects

OBJECTIVETo 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.

METHODSSixty 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).

RESULTSImmunohistochemistry, 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].

CONCLUSIONIncreased expression of the kidney inner medullary AQP2 and the excretion of urine AQP2 in chronic heart failure rats could be reduced by perindopril.

Animals ; Aquaporin 2 ; metabolism ; urine ; Disease Models, Animal ; Heart Failure ; metabolism ; Kidney ; drug effects ; metabolism ; Male ; Perindopril ; pharmacology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the effect of Yixintai Granule (YG) on mRNA and protein expression levels of AQP2 in renal medulla of chronic heart failure (CHF) rabbits.

METHODSCHF 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.

RESULTSCompared 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.

CONCLUSIONYG could improve CHF possibly through down-regulating mRNA and protein expression levels of AQP2 in renal medulla, and elevating the urine volume.

Animals ; Aquaporin 2 ; genetics ; metabolism ; Chronic Disease ; Drugs, Chinese Herbal ; administration & dosage ; pharmacology ; therapeutic use ; Heart Failure ; drug therapy ; metabolism ; RNA, Messenger ; metabolism ; Rabbits ; Rats, Sprague-Dawley

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.
Animals ; Aquaporin 2 ; genetics ; metabolism ; Blood Circulation ; drug effects ; Diuresis ; drug effects ; Drugs, Chinese Herbal ; administration & dosage ; Humans ; Kidney ; blood supply ; drug effects ; metabolism ; physiopathology ; Kidney Diseases ; drug therapy ; genetics ; metabolism ; physiopathology ; Male ; Rats ; Salvia miltiorrhiza ; chemistry

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.
Animals ; Aquaporin 2 ; metabolism ; Cell Line ; Cyclic AMP-Dependent Protein Kinases ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Kidney ; cytology ; Male ; RNA, Messenger ; Rats ; Rats, Sprague-Dawley ; Receptors, Vasopressin ; metabolism ; Signal Transduction

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.
Rats ; Animals ; AMP-Activated Protein Kinases/metabolism* ; Rats, Sprague-Dawley ; Cholesterol, LDL ; Fermentation ; Aquaporin 2/metabolism* ; Lipid Metabolism ; Liver ; Lipids ; Hyperlipidemias/genetics* ; Adenosine Triphosphate/pharmacology* ; Diet, High-Fat/adverse effects*