Cg. Duarte et al., Effects of radiocontrast, mannitol, and endothelin on blood pressure and renal damage in the aging male spontaneously hypertensive rat, INV RADIOL, 34(7), 1999, pp. 455-462
Citations number
48
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
RATIONALE AND OBJECTIVES. The purpose of this research was to study the eff
ects of the radiocontrast medium (CM) Hypaque-76 (diatrizoate meglumine sod
ium), equiosmolar mannitol, and endothelin on blood pressure and renal dama
ge in a aging male spontaneously hypertensive rat, a small animal model for
CM-induced renal damage. The importance of the presser effect and the high
osmolality of CM in producing renal damage was investigated by first reduc
ing the blood pressure with pentobarbital anesthesia, which suppresses symp
athetic nervous system activity, then testing the effects of CM, saline, ma
nnitol, and the potent vasoconstrictor endothelin alone and in combination
with CM.
METHODS. Systolic blood pressure was measured in 14-month-old male rats (1)
when awake, (2) after pentobarbital anesthesia, (3) after the administrati
on of saline, CM, mannitol, endothelin, or CM plus endothelin, (4) after aw
akening the same day, and (5) the following day while awake. Renal damage w
as quantified by evaluating histopathologically the left kidney removed the
day after administration of test substances.
RESULTS. The pentobarbital-lowered blood pressure remained depressed after
saline and mannitol but rose dramatically after CM, endothelin, and CM plus
endothelin. Renal damage, compared with the saline controls, occurred with
CM, mannitol, endothelin, and endothelin plus CM. The order of increasing
severity was mannitol = CM < endothelin < endothelin plus CM.
CONCLUSIONS. The effect of CM on systolic blood pressure is not related to
its osmolality. High osmolality, however, appears to be a factor in CM-indu
ced renal damage. Ischemia and direct nephrotoxicity are factors contributi
ng to the renal-damaging effects of CM, mannitol, and endothelin.