Protein-restricted diet prior to renal insult improves the recovery of renal function following ischemia.

The effects of a protein-restricted diet on renal recovery following renal ischemia were studied. The renal function was assessed by measuring the inulin clearance (CIN), the p-aminohippurate clearance (CPAH), and the percent fractional sodium excretion (%FENa) 24 h after 45 min renal ischemia. In rats fed with a regular diet (containing 19.6% protein), CIN was 10.0 +/- 2.2 microL/min/100 g body weight (BW), CPAH 0.08 +/- 0.02 mL/min/100 g BW, and %FENa 14.8 +/- 2.0, 24 h after renal ischemia. In contrast, feeding rats with a no-protein diet (0% protein) for 1 week prior to the ischemic insult significantly improved renal recovery (CIN 48.0 +/- 9.3 microL/min/100 g BW, CPAH 0.16 +/- 0.04 mL/min/100 g BW, and %FENa 2.43 +/- 0.58). Feeding rats with a no-protein diet for 3 weeks prior to ischemic insult further improved the renal recovery (CIN 113 +/- 30 microL/min/100 g BW, CPAH 0.47 +/- 0.17 mL/min/100 g BW, and %FENa 1.55 +/- 0.29). When rats fed with a regular diet were exposed to 45 min of ischemia, the survival rate on day 7 was 16.7%. In rats fed with the no-protein diet for 1 week and for 3 weeks, the 7-day survival rate was 100% in each case. The survival rate of rats fed for 3 days instead of 7 days with the no-protein diet was 87.5%. When a no-protein feeding was shortened to 1 day, no beneficial effects were observed and survival rate was 14.3%. (ABSTRACT TRUNCATED AT 250 WORDS)