The contribution of hypoxia to postischemic renal dysfunction.
Renal ischemia is a multifactorial insult consisting of both hypoxia and stagnation of blood flow. This study compared the renal response with hypoxia alone versus ischemia (hypoxia and stagnation of flow). Isolated rat kidneys were perfused at 90 to 110 mm Hg and 37 degrees C with an asanguinous modified Krebs' buffer. Perfusate flow rate, vascular resistance, urine flow rate, glomerular filtration rate (GFR), percent sodium reabsorption, and oxygen consumption were measured. Five groups were examined: 10-minute hypoxia (HYP10), 30-minute hypoxia (HYP30), 10-minute ischemia (ISC10), 30-minute ischemia (ISC30), and time-matched controls. HYP10 resulted in isolated tubular dysfunction, as evidenced by an increase in urine flow rate and a decrease in percent sodium reabsorption. ISC10 caused decreased GFR, oliguria, and more severe tubular dysfunction. The pattern of glomerular and tubular dysfunction after HYP30 was similar to that after ISC30. Glomerular dysfunction was associated with a decrease in perfusate flow rate and an increase in vascular resistance only after ISC30. This suggests that the decrease in GFR seen with postischemic renal dysfunction is not a primary result of decreased flow. Furthermore, hypoxia does not account for the entire reduction in renal function after ischemia of similar duration. The more severe dysfunction after ischemia may be a consequence of the stagnation of renal flow (anaerobic waste product accumulation and inadequate nutrient supply).
Galat
J A
JA
Department of Surgery, Case Western Reserve University, Cleveland, OH 44106.
Robinson
A V
AV
Rhodes
R S
RS
D000818:Animals; D004231:Diuresis; D005919:Glomerular Filtration Rate; D000860:Hypoxia / Q000503:physiopathology*; D007511:Ischemia / Q000503:physiopathology; D007668:Kidney / Q000098:blood supply* / Q000503:physiopathology; D008297:Male; D010101:Oxygen Consumption; D051381:Rats; D011919:Rats, Inbred Strains; D012079:Renal Circulation; D012964:Sodium / Q000378:metabolism; D013997:Time Factors; D014655:Vascular Resistance
D012964:Sodium