Background

Lipid peroxidation impairs renal function. Aldosterone contributes to renal injury in the remnant kidney model. This study aimed to determine the effects of the antioxidant N-acetylcysteine (NAC) on renal function and aldosterone levels in chronic renal failure.

Methods

Adult male Wistar rats were submitted to 5/6 nephrectomy or laparotomy (sham-operated) and received NAC (600 mg/L in drinking water, initiated on postoperative day 7 or 60), spironolactone (1.5 g/kg of diet initiated on postoperative day 7), the NAC-spironolactone combination or no treatment. Clearance studies were performed on postoperative days 21, 60, and 120.

Results

Mean daily NAC and spironolactone ingestion was comparable among the treated groups. Mean weight gain was higher in NAC-treated rats than in untreated rats. A significant decrease in urinary thiobarbituric acid reactive substances (TBARS) concentrations, a lipid peroxidation marker, was observed in NAC-treated rats. By day 120, glomerular filtration rate (GFR), which dropped dramatically in untreated rats, was stable (albeit below normal) in NAC-treated rats, which also presented lower proteinuria, glomerulosclerosis index, and blood pressure, together with attenuated cardiac and adrenal hypertrophy. These beneficial effects, observed even when NAC was initiated on postnephrectomy day 60, were accompanied by a significant reduction in plasma aldosterone and urinary sodium/potassium ratio. The NAC-spironolactone combination lowered blood pressure and improved GFR protection.

Conclusion

The NAC-spironolactone combination improves renal function more than does NAC alone. In the remnant kidney model, early or late NAC administration has a protective effect attributable to decreased plasma aldosterone and lower levels of lipid peroxidation.

CONCLUSION

Our data demonstrate that NAC attenuates drops in GFR, as well as lowering proteinuria and blood pressure in nephrectomized rats. This is accompanied by a significant reduction in aldosterone levels. Our results indicate that ROS play an important role in the progression of chronic renal failure. It is evident that NAC has potential utility in preventing glomerulosclerosis and loss of kidney function in patients with chronic renal failure. The findings that NAC attenuated GFR drop and lowered proteinuria, even in end-stage chronic renal failure, and that the combination of NAC and spironolactone improves renal function more than does NAC alone have significant clinical implications.

Source: Nature Kidney