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Background: Whole-body vibration (WBV) is used to enhance physical performance in sports and rehabilitation. The present study analyzed the effects of remobilization with WBV on the soleus muscle of Wistar rats. Methods: Twenty-eight animals were separated into four experimental groups (n = 7): CON (control); IM (immobilized); FR (immobilization and free remobilization); and WBV (immobilization and remobilization with WBV). The immobilization of the pelvic limb was carried out according to the standard protocol using a plaster cast for 15 days. For remobilization with WBV, a Frequency of 60 Hz was applied for 10 min, five days a week, for two weeks. After the remobilization period, the animals were euthanized, and the right soleus muscle was dissected followed by processing for histomorphometric analysis and immunolocalization of Aquaporin 1 (AQP1). Results: We observed a reduced larger diameter in IM compared to CON, with restored values in WBV. For the estimation of connective tissue, a significant increase was observed in the immobilized groups, while a reduction was noted in the remobilized groups. AQP1 expression decreased significantly in IM and increased in WBV. Conclusion: Immobilization caused morphofunctional damage to the soleus muscle, and remobilization with WBV is efficient and offers advantages over free remobilization.

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Diabetic nephropathy (DN) is a prevalent diabetic microvascular condition. It is the leading cause of kidney disease in the advanced stages. There is no currently effective treatment available. This research aimed to investigate the curative potentials of exosomes isolated from mesenchymal stem cells affecting DN. This study was performed on 70 male adult albino rats. Adult rats were randomized into seven groups: Group I: Negative control group, Group II: DN group, Group III: Balanites treated group, Group IV: MSCs treated group, Group V: Exosome treated group, Group VI: Balanites + MSCs treated group and Group VII: Balanites + exosome treated group. Following the trial period, blood and renal tissues were subjected to biochemical, gene expression analyses, and histopathological examinations. Results showed that MDA was substantially increased, whereas TAC was significantly decreased in the kidney in the DN group compared to normal health rats. Undesired elevated values of MDA levels and a decrease in TAC were substantially ameliorated in groups co-administered Balanites aegyptiacae with MSCs or exosomes compared to the DN group. A substantial elevation in TNF-α and substantially diminished concentration of IGF-1 were noticed in DN rats compared to normal health rats. Compared to the DN group, the co-administration of Balanites aegyptiacae with MSCs or exosomes substantially improved the undesirable elevated values of TNF-α and IGF-1. Furthermore, in the DN group, the mRNA expression of Vanin-1, Nephrin, and collagen IV was significantly higher than in normal healthy rats. Compared with DN rats, Vanin-1, Nephrin, and collagen IV Upregulation were substantially reduced in groups co-administered Balanites aegyptiacae with MSCs or exosomes. In DN rats, AQP1 expression was significantly lower than in normal healthy rats. Furthermore, the groups co-administered Balanites aegyptiacae with MSCs or exosomes demonstrated a substantial increase in AQP1 mRNA expression compared to DN rats.

A nefropatia diabética (ND) é uma condição microvascular diabética prevalente. É a principal causa de doença renal em estágios avançados. Atualmente, não há tratamento eficaz disponível. Esta pesquisa teve como objetivo investigar os potenciais curativos de exossomos isolados de células-tronco mesenquimais que afetam a ND. Este estudo foi realizado em 70 ratos albinos adultos machos. Ratos adultos foram randomizados em sete grupos: Grupo I: Grupo de controle negativo, Grupo II: Grupo DN, Grupo III: Grupo tratado com Balanites, Grupo IV: Grupo tratado com MSCs, Grupo V: Grupo tratado com exossomos, Grupo VI: Grupo tratado com Balanites + MSCs e Grupo VII: Balanites + grupo tratado com exossomas. Após o período experimental, o sangue e os tecidos renais foram submetidos a análises bioquímicas, de expressão gênica e exames histopatológicos. Os resultados mostraram que o MDA aumentou substancialmente, enquanto o TAC diminuiu significativamente no rim no grupo DN em comparação com ratos saudáveis normais. Valores elevados indesejados de níveis de MDA e uma diminuição no TAC foram substancialmente melhorados em grupos coadministrados Balanites aegyptiacae com MSCs ou exossomas em comparação com o grupo DN. Uma elevação substancial em TNF-α e uma concentração substancialmente diminuída de IGF-1 foram observadas em ratos DN em comparação com ratos saudáveis normais. Em comparação com o grupo DN, a coadministração de Balanites aegyptiacae com MSCs ou exossomas melhorou substancialmente os valores elevados indesejáveis de TNF-α e IGF-1. Além disso, no grupo DN a expressão de mRNA de vanina-1, nefrina e colágeno IV foi significativamente maior do que em ratos saudáveis normais. Comparado com ratos DN, Vanin-1, Nephrin e colágeno IV Upregulation foram substancialmente reduzidos em grupos co-administrados Balanites aegyptiacae com MSCs ou exossomos. Em ratos DN, a expressão de AQP1 foi significativamente menor do que em ratos saudáveis normais. Além disso, os grupos que coadministraram Balanites aegyptiacae com MSCs ou exossomos demonstraram um aumento substancial na expressão de mRNA de AQP1 em comparação com ratos DN.

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The physiological variations during the crustacean molting cycle have intrigued researchers for many years. Maintaining osmotic homeostasis in the face of hemolymph dilution and dealing with dynamic intracellular and extracellular calcium fluctuations are challenges these animals continuously confront. It has recently been shown that water channels present in the cell membrane (aquaporins) are essential for water uptake during premolt and postmolt. This study aims to investigate whether hypoosmotic shock and intracellular and extracellular calcium variations can lead to translocation of Aquaporin 1 (AQP-1) from the intracellular region to the plasma membrane during premolt and postmolt, thus allowing increased water flow in these stages. For this, we investigate in vitro the rapid change of AQP-1 positions in the abdominal muscle cells in the freshwater shrimp, Palaemon argentinus. Using cell volume analysis and immunohistochemistry, we show that hypoosmotic conditions and an elevation of the intracellular and extracellular calcium concentrations are concurrent with the translocation of AQP-1 to the plasma membrane. These results indicate that calcium flux and hypoosmotic shock may be regulators of AQP 1 in the translocation process.

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SUMMARY: The expression of aquaporin-1 (AQP1) in choroid plexus and aquaporin-4 (AQP4) in astrocyte of the hippocampal formation (HF) was studied in the rat to determine the role of AQP1 and AQP4 in the pathophysiology of systemic hyponatremia (SH). SH was induced by coadministration of dextrose solution intraperitoneally and through subcutaneous implantation of an osmotic minipump containing 8-deamino-arginin vasopressin (50ng/µl/h) for 24 and 48 h. Twenty- four and 48 h after the drug administration, there were significant reductions in Na+ concentration (111 ± 5 and 104 ± 2 mmol) and serum osmolarity (240 ± 13 and 221 ± 14 mOsm/L) as compared with control values (140 ± 4.7 mmol and 296 ± 5.2 mOsm/L), (p<0.01). The expression of AQP1 in the choroid plexus was increased three to five times from 24 h to 48 h after SH (329.86 ± 10.2 % and 531.5 ± 4.4 %, n=4, p<0.01). In contrast, AQP4 expression was significantly decreased up to 48 h after SH (36 ± 9 %, n=4, p<0.01). Quantitative immunoblotting revealed significant decreases of neuronal proteins in the HF after 24 to 48 h of SH. Therefore, we suggest that altered expression of AQP1 and AQP4 plays important role in the pathogenesis of systemic hyponatremia.

RESUMEN: En este análisis se estudió la expresión de acuaporina-1 (AQP1) en plexo coroideo y acuaporina-4 (AQP4) en astrocitos de la formación hipocampal (FH) en ratas para determinar el papel de AQP1 y AQP4 en la fisiopatología de la hiponatremia sistémica (HS). La HS fue inducida mediante la coadministración de solución de dextrosa por vía intraperitoneal y mediante la implantación subcutánea de una minibomba osmótica que contenía vasopresina 8-desaminoarginina (50 ng /µ l / h) durante 24 y 48 h. Veinticuatro y 48 h después de la administración del fármaco, hubo reducciones significativas en la concentración de Na + (111 ± 5 y 104 ± 2 mmol) y la osmolaridad sérica (240 ± 13 y 221 ± 14 mOsm /µL) en comparación con los valores de control (140 ± 4,7 mmol y 296 ± 5,2 mOsm / L), (p <0,01). La expresión de AQP1 en el plexo coroideo se incrementó de tres a cinco veces de 24 a 48 h después de HS (329,86 ± 10,2 % y 531,5 ± 4,4 %, n = 4, p <0,01). Por el contrario, la expresión de AQP4 se redujo significativamente hasta 48 h después de HS (36 ± 9 %, n = 4, p <0,01). La inmunotransferencia cuantitativa reveló disminuciones significativas de proteínas neuronales en el FH después de 24 a 48 h de SH. Por lo tanto, sugerimos que la expresión alterada de AQP1 y AQP4 juega un papel importante en la patogénesis de la hiponatremia sistémica.

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Salivary gland aquaporins (AQPs) are essential for the control of saliva production and maintenance of glandular structure. However, little is known of their role in salivary gland neoplasia. Salivary gland tumors comprise a heterogeneous group of lesions, featuring variable histological characteristics and diverse clinical behaviors. Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy. The aim of this study was to evaluate the expression of AQP1, AQP3, and AQP5 in 24 MEC samples by immunohistochemistry. AQP1 expression was observed in vascular endothelium throughout the tumor stroma. AQP3 was expressed in epidermoid and mucosal cells and AQP5 was expressed in mucosal cells of MEC. These proteins were expressed in the human MEC cell line UH-HMC-3A. Cellular ultrastructural aspects were analyzed by electron microscopy to certificate the tumor cell phenotype. In summary, our results show that, despite the fact that these molecules are important for salivary gland physiology, they may not play a distinct role in tumorigenesis in MEC. Additionally, the in vitro model may offer new possibilities to further investigate mechanisms of these molecules in tumor biology and their real significance in prognosis and possible target therapies.

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OBJECTIVES: Cardiopulmonary bypass (CPB) use is an essential strategy for many cardiovascular surgeries. However, its use and duration have been associated with a higher rate of postoperative complications, such as low cardiac output syndrome due to myocardial oedema and dysfunction. Though Aquaporin water channels have been implicated in myocardial water balance, their specific role in this clinical scenario has not been established. METHODS: In a consecutive study of 17 patients with severe aortic stenosis undergoing aortic valve replacement surgery, 2 myocardial biopsies of the left ventricle were taken: 1 before and 1 after CPB use. Sociodemographic, clinical and laboratory data were collected. Western blot and immunohistochemistry studies were performed. RESULTS: After CPB use, there was a mean increase of ∼62% in Aquaporin 1 protein levels (P = 0.001) and a mean reduction of ∼38% in Aquaporin 4 protein levels (P = 0.030). In immunohistochemistry assays, Aquaporin 1 was found lining small blood vessels, while Aquaporin 4 formed a circular label in cardiomyocytes. There were no changes in the localization of either protein following CPB use. During the observed on-pump time interval, there was a 1.7%/min mean increase in Aquaporin 1 (P = 0.021) and a 2.5%/min mean decrease in Aquaporin 4 (P = 0.018). Myocardial interstitial oedema increased by 42% (95% confidence interval 31-54%) after CPB use. Patients who developed low cardiac output syndrome were in the upper half of the median percentage change of Aquaporin expression. CONCLUSION: Time-dependent changes in cardiac Aquaporin expression may be associated with myocardial oedema and dysfunction related to CPB use.

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Water influx through aquaporin-1 (AQP-1) has been linked to the ability of different cell types to migrate, and therefore plays an important part in processes like metastasis and angiogenesis. Since the erythroid growth factor erythropoietin (Epo) is now recognized as an angiogenesis promoter, we investigated the participation of AQP-1 as a downstream effector of this cytokine in the migration of endothelial cells. Inhibition of AQP-1 with either mercury ions (Hg2+) or a specific siRNA led to an impaired migration of EA.hy926 endothelial cells exposed to Epo (wound-healing assays). Epo also induced the expression of AQP-1 at mRNA and protein levels, an effect which was dependent on the influx of extracellular calcium through L-type calcium channels as well as TRPC3 channels. The relationship between Epo and AQP-1 was further confirmed at shorter exposure times, as the cytokine was unable to trigger calcium influxes in cells where AQP-1 had previously been knocked down. Moreover, Epo promoted changes in the subcellular localization of AQP-1 as well as rearrangements in the actin cytoskeleton, which are consistent with a migratory phenotype. Worthy of note, carbamylated erythropoietin (cEpo), the non-erythropoietic and non-promigratory derivative of Epo, was incapable of AQP-1 modulation. The therapeutical implications of aquaporin targeting in angiogenesis-related diseases highlight the importance of the present results in the context of the relationship between AQP-1 and Epo.

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BACKGROUND: Mesenchymal stem cells (MSC) improve renal function and renovascular hypertension in the 2-kidney 1-clip model (2K-1C). While MSC play an immunomodulatory role, induce neoangiogenesis, and reduce fibrosis, they do not correct sodium loss by the contra-lateral kidney. OBJECTIVES: We investigated the tubular function of both stenotic and contralateral kidneys and the effect of MSC treatment by evaluating diuresis, natriuresis, and the expression of the main water and sodium transporters. METHOD: Adult Wistar rats were allocated into four groups: control (CT), CT+MSC, 2K-1C, and 2K-1C+MSC. MSC (2 × 105) were infused through the tail vein 3 and 5 weeks after clipping. Systolic blood pressure (SBP) was monitored weekly by plethysmography. Six weeks after clipping, 24-hour urine and blood samples were collected for biochemical analysis. Gene expression of the Na/H exchanger-3, epithelial sodium channel, Na/K-ATPase, Na/K/2Cl cotransporter, and aquaporins 1 and 2 (AQP1 and AQP2) were analyzed by RT-PCR. Intrarenal distribution of AQP1 and AQP2 was analyzed by immunohistochemistry. RESULTS: In hypertensive 2K-1C animals, MSC prevented additional increases in BP. AQP1, but not AQP2, was suppressed in the contralateral kidney, resulting in significant increase in urinary flow rate and sodium excretion. Gene expressions of sodium transporters were similar in both kidneys, suggesting that the high perfusing pressure in the contralateral kidney was responsible for increased natriuresis. Contralateral hypertensive kidney showed signs of renal deterioration with lower GFR in spite of normal RPF levels. CONCLUSIONS: MSC treatment improved renal function and enhanced the ability of the contralateral kidney to excrete sodium through a tubular independent mechanism contributing to reduce SBP.

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One of the key functions of the hepatobiliary system is bile formation. Aquaporins (AQPs) are likely to play a role in water transport that is essential for appropriate hepatobiliary tract function. The increasing prevalence of fatty liver parallels the rise of obesity and its complications over the past several decades. In this paper, general morphology observation, histopathology and AQP1 immunohistochemical expression were observed in livers of the high-fat diet (HFD) rats. For the liver of HFD rats, immunolight microscopy revealed weak labeling of AQP1 on the surface of central veins and liver sinusoid compared with the normal diet (ND) rats. It was suggested that bile secreted by the liver of HFD rats was maybe abnormal, thereby causing abnormalities in the composition and secretion of bile. However, the deeper understanding of mechanisms involved to the fatty liver is still unclear, in particular AQPs in the liver of obesity, additional studies would be required to study the signalling cascades involved in these processes.

Una de las funciones clave del sistema hepatobiliar es la formación de bilis. Es probable que las acuaporinas (AQP) desempeñen un papel en el transporte de agua que es esencial para la función apropiada del tracto hepatobiliar. En las últimas décadas, la creciente prevalencia de hígado graso es paralela al aumento de la obesidad y sus complicaciones. En este trabajo, se identificaron características morfológicas generales, histopatología y expresión inmunohistoquímica de AQP1 en hígados de ratas con dieta rica en grasas (DRG). En el hígado de ratas con DRG, la expresión inmunohistoquímica determinó un marcaje débil de AQP1 en la superficie de las venas centrales y del sinusoide hepático en comparación con las ratas de dieta normal (DN). Se sugirió que la bilis secretada por el hígado de ratas con DRG era tal vez anormal, lo que causaba anomalías en la composición y secreción de la bilis. Sin embargo, se necesita un conocimiento mayor de los mecanismos involucrados en el hígado graso, en particular de las AQP y se requieren estudios adicionales para determinar las cascadas de señalización involucradas en estos procesos.

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