Estudo dos transportadores renais de Na, K e água e da hemodinâmica sistêmica em fêmeas prenhes normotensas e hipertensas

• Ano de defesa: 2006
• Autor(a) principal: Abreu, Nayda Parisio de [UNIFESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Hemodinâmica sistêmica; Transportadores do néfron; Prenhez; Hipertensão; Systemic hemodynamic; Nephron transporters; pregnancy; Hypertension
• Link de acesso: http://repositorio.unifesp.br/handle/11600/9575

Introduction: Extracelular volume expansion (ECVE) followed by decrease in vascular resistance, increase in renal plasma flow and glomerular hiperfiltration are common manifestations during normal pregnancy. Nitric oxide appears to be directly involved in the systemic alterations during pregnancy. Also, renal water and salt retention may play a role in these manifestations. Aim: The aim of this study was evaluate if the alterations in ECVE observed during normal and hypertensive pregnancy (by NO blocking) are parallel with changes in the mRNA expression levels of renal electrolytes and water transporters Methods: Wistar rats were divided in control group (C, n=5); pregnancy (P, n=5); hypertension (H, n=6) (L-NAME, 50 mg/Kg/day) and, hypertension + pregnancy (HP, n=6). The hemodynamic parameters including mean arterial pressure (MAP), heart rate (HR), stroke volume (SV), total peripheral resistance (TPR) and cardiac output (CO) were analyzed at 14th day of pregnancy. The mRNA expression levels of Na/H exchanger (NHE3), Na/K/2Cl cotransporter (BSC), K channel (ROMK2) and the aquaporin 2 (AQP2) were analyzed in the kidney tissue by Real Time-PCR technique. Results: The P group showed CO higher then C rats (P, 107±7 vs C, 84±5 ml/mim, p<0.05) without elevation in blood pressure (P, 118±2 vs C, 116±3 mmHg). The H group showed CO lower then C group (H, 44.1±2.2 vs C, 84.5±1.2; p<0.05) with significant elevation in MAP (H, 170.7±9.0 vs C, 119.4±7.4; p<0.05). Rats form HP group showed higher in TPR when compared with P group (HP, 3.5±0.4 vs P, 1.2±0.1; p<0.05) and decrease in SV (HP, 256.6±24.4 vs P, 115.5±20.5). All data of renal transporters expression are presented in arbitrary units. P rats showed decrease in ROMK2 mRNA expression (P, 0.3±0.04 vs C, 2.3±0.5, p<0.05) and increase in AQP2 (P, 3.5±0.2 vs C, 1.3±0.2, p<0.05). The H group showed significant increase in AQP2 expression when compared with C and HP groups (2.6±0.4 vs 1.3±0.2 e 1.2±0.1, respectively, p<0.05). HP showed decrease in BSC and NHE3 expression compared with P group (0.2±0.07 vs 0.8±0.2 e 1.2±0.1 vs 1.6±0.2, respectively, p<0.05). Conclusion: The hypertension induced by NO synthesis inhibition blunted systemic hemodynamic adaptations during the pregnancy. The pregnant hypertensive rats presented nephron transporters alterations (reduction in the ROMK2, BSC and NHE3 expression with increase in AQP2 expression). These data suggest that a variation on tubular transporters could mediate the hemodynamic adaptations modulate by NO during pregnancy.