Efeito de células tronco mesenquimais sobre a expressão de transportadores de água e eletrólitos no rim de ratos hipertensos com estenose da artéria renal
Data
2017-09-28
Autores
Varela, Vanessa Araujo 
Orientadores
Boim, Mirian Aparecida
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Estudos prévios mostraram que células tronco mesenquimais (CTM) melhoram a função renal e a hipertensão renovascular (HRV) induzida por clampeamento da artéria renal, modelo 2 Rins 1 Clipe (2R-1C), através de efeitos parácrinos, imunomodulatórios e angiogênicos com redução da fibrose do rim estenótico (RE) e do contralateral (RC). Animais com HRV apresentam poliúria cuja causa não é conhecida e a qual não foi corrigida pelo tratamento com CTM. No presente estudo, avaliamos a participação de transportadores de sódio e água na diurese e natriurese apresentada por animais 2R-1C e o efeito de CTM sobre a expressão desses transportadores. Ratos Wistar machos e adultos foram dispostos nos seguintes grupos: controle (CT), CT tratados com CTM (CT+CTM), hipertensos (2R-1C) e hipertensos tratados (2R-1C+CTM). As CTM foram obtidas da medula óssea de ratos Wistar e infundidas (2x105 células, iv), na 3ª e 5ª semanas após o clampeamento da artéria renal esquerda. Pressão arterial sistólica (PAS) foi monitorada semanalmente. Seis semanas após o clampeamento, urina de 24 horas, sangue e rins foram coletados para análises bioquímicas, moleculares e histológicas. Em outra série, animais de cada grupo foram utilizados para estimar o ritmo de filtração glomerular (RFG) e o fluxo sanguíneo renal (FSR) do RE e do RC. A expressão dos transportadores: trocador Na/H (NHE3), canal de sódio (ENaC), bomba Na/K/ATPase, cotransportador Na/K/2Cl e das aquaporinas 1 e 2 (AQP1 e AQP2) foi avaliada por RT-PCR em tempo real, western blot e imunohistoquímica. A poliúria dos animais hipertensos ocorreu às custas de aumento na diurese e na natriurese do RC uma vez que esses parâmetros foram reduzidos no RE. Não foram detectadas modificações significantes na expressão de nenhum dos transportadores de sódio tanto no RE quanto no RC, sugerindo que a natriurese apresentada pelo RC foi de origem pressórica. A expressão de AQP1 foi discretamente reduzida apenas na medula do RE, porém foi significantemente suprimida tanto no córtex como na medula do RC. A expressão de AQP2 não foi modificada. Esses resultados sugerem que a poliúria apresentada pelos animais hipertensos tem pelo menos duas origens, a natriurese pressórica e a redução na capacidade de reabsorção de água por redução da AQP1 no RC. O tratamento com CTM não induziu modificações significantes no perfil de expressão dos transportadores indicando que a capacidade do RC em excretar sódio e água foi mantida durante o tratamento. Em conclusão, o tratamento com CTM foi eficaz para minimizar a HRV, e contribuiu para preservar a capacidade do RC em excretar sódio e água.
Previous studies have shown that mesenchymal stem cells (MSC) improve renal function and renovascular hypertension (RVH) induced by renal artery clamping, 2 Kidneys 1 Clip (2K-1C) model through paracrine, immunomodulatory and angiogenic effects with reduction of fibrosis in both stenotic (SK) and contralateral (CK) kidneys. Animals with RVH presented polyuria whose cause is not completely known. MSC treatment did not modify RVH-induced polyuria. In this study, we evaluated the participation of sodium and water transporters in the polyuria presented by 2K-1C animals and the effect of MSC on the expression of these transporters. Male and adult Wistar rats were allocated into the following groups: control (CT), MSC treated (CT + MSC), hypertensive (2K-1C) and hypertensive treated (2K-1C + MSC). MSC were obtained from the bone marrow of Wistar rats and infused (2x105 cells, iv) at the 3rd and 5th weeks after clamping of the left renal artery. Systolic blood pressure (SBP) was monitored weekly. Six weeks after clamping, 24 hour urine, blood and kidneys were collected for biochemical, molecular and histological analyzes. In another series, animals from each group were used to estimate the glomerular filtration rate (GFR) and renal blood flow (RBF) of SK and CK. Expression of the transporters: Na/H exchanger (NHE3), sodium channel (ENaC), Na/K/ATPase, Na/K/2Cl cotransporter and aquaporin 1 and 2 (AQP1 and AQP2) was evaluated by RT-PCR in Real-time, western blot and immunohistochemistry. The polyuria of the hypertensive animals was consequent to the increase in the diuresis and the natriuresis of the CK since these parameters were reduced in the SK. No significant changes were detected in the expression of any of the sodium transporters in both SK and CK, suggesting that the natriuresis presented by CK was of pressure origin. The AQP1 expression was slightly reduced only in the medulla of the SK, but was significantly suppressed in both the cortex and the medulla of the CK. The expression of AQP2 was not modified. These results suggest that at least two mechanisms are responsible for the polyuria presented by the hypertensive animals, the pressure natriuresis and the reduction in the water reabsorption capacity by reducing the AQP1 in CK. MSC treatment did not induce significant modifications in the expression profile of transporters indicating that the ability of CK in excreting sodium and water was preserved during treatment. In conclusion, MSC treatment was effective in minimizing RVH, and contributed to preserve the ability of CK in excreting sodium and water.
Previous studies have shown that mesenchymal stem cells (MSC) improve renal function and renovascular hypertension (RVH) induced by renal artery clamping, 2 Kidneys 1 Clip (2K-1C) model through paracrine, immunomodulatory and angiogenic effects with reduction of fibrosis in both stenotic (SK) and contralateral (CK) kidneys. Animals with RVH presented polyuria whose cause is not completely known. MSC treatment did not modify RVH-induced polyuria. In this study, we evaluated the participation of sodium and water transporters in the polyuria presented by 2K-1C animals and the effect of MSC on the expression of these transporters. Male and adult Wistar rats were allocated into the following groups: control (CT), MSC treated (CT + MSC), hypertensive (2K-1C) and hypertensive treated (2K-1C + MSC). MSC were obtained from the bone marrow of Wistar rats and infused (2x105 cells, iv) at the 3rd and 5th weeks after clamping of the left renal artery. Systolic blood pressure (SBP) was monitored weekly. Six weeks after clamping, 24 hour urine, blood and kidneys were collected for biochemical, molecular and histological analyzes. In another series, animals from each group were used to estimate the glomerular filtration rate (GFR) and renal blood flow (RBF) of SK and CK. Expression of the transporters: Na/H exchanger (NHE3), sodium channel (ENaC), Na/K/ATPase, Na/K/2Cl cotransporter and aquaporin 1 and 2 (AQP1 and AQP2) was evaluated by RT-PCR in Real-time, western blot and immunohistochemistry. The polyuria of the hypertensive animals was consequent to the increase in the diuresis and the natriuresis of the CK since these parameters were reduced in the SK. No significant changes were detected in the expression of any of the sodium transporters in both SK and CK, suggesting that the natriuresis presented by CK was of pressure origin. The AQP1 expression was slightly reduced only in the medulla of the SK, but was significantly suppressed in both the cortex and the medulla of the CK. The expression of AQP2 was not modified. These results suggest that at least two mechanisms are responsible for the polyuria presented by the hypertensive animals, the pressure natriuresis and the reduction in the water reabsorption capacity by reducing the AQP1 in CK. MSC treatment did not induce significant modifications in the expression profile of transporters indicating that the ability of CK in excreting sodium and water was preserved during treatment. In conclusion, MSC treatment was effective in minimizing RVH, and contributed to preserve the ability of CK in excreting sodium and water.