ENDOGENOUS NITRlC OXIDE ROLE IN RENAL NEONATAL APOPTOSIS

WALTER MANUCHA; LILIANA CARRIZO; CELESTE RUETE; PATRICIA G. VALLES

Merlo - San Luis - Argentina

Congreso; XXII Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2004

Siciedad de Biología de Cuyo y Sociedad Argentina de Microscopía

Unilateral ureteral obstruction (UUO) is associated with apoptosis, through a mechanism not yet completely elucidated. Angiotensin II and nitric oxide (NO) have been involved in apoptosis activation. In a model of neonatal UUO, we studied whether endogenous NO is involved in renal apoptosis induction. Newborn rats were subjected to UUO (n:10) within the first 48 h of life. After 5 and 14 days, kidneys were removed. Results: Decreased expression of AT2 receptor at 14 day relief vs 5 day relief in control cortex (CC): 0.497± 0.2 vs 0.993± 0.5 (p < 0.01) and obstructed cortex (OC) 0.566± 0.3 vs 0.974± 0.3 (p < 0.01) (RT-PCR). lncrease in the number of apoptotic cells in cortical collecting ducts (CCD) proximal tubules (PT) in OC related to CC (TUNEL), and near two fold increase Bax/Bcl2 ratio after  4 days of obstruction (RT-PCR). Decreased iNOS expression in OC (p < 0.01). On the contrary, slight increase of tubular apoptotic cells in OC and Bax/Bcl2 ratio with simultaneous increase in iNOS expression related to control: 1.253± 0.07 vs 0.767 ±0.08 (p<0.01) after 5 days of obstruction. lncreased TGFá expression was shown after 14 days of obstruction (RT-PCR). The present study suggests a protective role of NO for apoptosis in neonatal renal obstruction including upregulation of Bcl2 as a mechanism from mitochondrial pathway.