Amino acids protects against renal ischemia-reperfusion injury and attenuates renal endothelin-1 disorder in rats.

OBJECTIVE: To investigate nephroprotective effects of a mixture of 8 L-amino acids on renal ischemia-reperfusion injury and its effects on renal endothelin-1 (ET-1).

METHODS: The mixture of 8 L-amino acids includes glycine, alanine, threonine, serine, valine, leucine, isoleucine and proline. Acute ischemic renal injury was induced by clamping renal pedicle for 45 minutes in rats. Sixty male Sprague-Dawley rats were randomly divided into 3 groups: a sham-operated group (Group A, n=8), a control group (Group B, n=26) and an amino acid-treated group (Group C, n=26). Amino acids were infused at a rate of 1 ml x 100g(-1) x h(-1) I hour before ischemia and during 3 hours of the whole reperfusion. The serum creatinine values, BUN levels, creatinine clearance, urine sodium and potassium excretion, urine lactate dehydrogenase (LDH), the rate of urine flow and histological examination were measured. Renal ET-1 levels were assayed with radioimmunological assay (RIA) RESULTS: The creatinine clearance was 471.0 microl/min+/-121.5 microl/min in Group C and 227.0 microl/min+/-27.0 microl/min in Group B 3 hours after reperfusion, P<0.01). The urine flow rate was 63.6 microl/min+/-15.2 microl/min in Group C and 24.3 microl/min+/-7.7 microl/minin Group B, P<0.01) 1.5 hours after reperfusion. The serum creatinine was 85.0 microl/min+/-7.7 micromol/L and BUN concentration 11.4 mmol/L+/-3.9 mmol/L in Group C and 112.7 micromol/L+/-19.5 micromol/L and 20.7 mmol/L+/-6.6 mmol/L respectively in Group B after 24 hours of reperfusion (P<0.05). The mean histological score by standards of Paller in kidneys was 108.7+/-15.7 in Group C, and 168.8+/-14.8in Group B (P<0.01). The renal ET-1 levels 15 minute and 3 hours after reperfusion were 7.2 pg/mg+/-0.8 pg/mg and 9.6 pg/ml+/-1.0 pg/ml in Group C, and 10.1 pg/ml+/-2.8 pg/ml and 13.0 pg/ml+/-2.7pg/ml in Group B (P<0.01).

CONCLUSIONS: The mixture of 8 L-amino acids can provide remarkable protection against renal ischemia-reperfusion injury in rats. This may associate with attenuation of renal ET-1 disorder.