Scintigraphic comparison of renal ischemia-reperfusion injury models in rats: correlations with biochemical and histopathological findings.

Objective: This study aimed to compare the effect on renal functions of ischemia-reperfusion (I-R) injury models by renal scintigraphy and to investigate possible correlations among scintigraphic, biochemical and pathological findings.

Methods: An experimental I-R injury was performed on the left kidneys of 40 Wistar rats: pedincular continuous clamping in Group 1 (n = 10), pedincular cyclic clamping in Group 2 (n = 10), arterial continuous clamping in Group 3 (n = 10) and arterial cyclic clamping in Group 4 (n = 10). A functional and morphological assessment was made by (99m)Tc-MAG3 scintigraphy, biochemical tests and histopathological examination in the late period of I-R injury. Data were analyzed statistically.

Results: Statistically significant differences were found in the peak counting (C max), normalized residual activity (NORA), renal retention (RR), split renal function (SRF) and the time to the C max (T max) parameters between the right and left kidneys in each group (p < 0.001). In multiple group comparisons for the left kidney statistically significant differences were determined for C max (F = 4.75, df = 3, p < 0.05), NORA (F = 4.362, df = 3, p < 0.05), RR (F = 10.49, df = 3, p < 0.001) and SRF (F = 4.17, df = 3, p < 0.05) but not T max (F = 1.13, df = 3, p > 0.05). The total scores of Groups 1, 2, 3, and 4 were, respectively, found to be 18, 30, 20 and 24 by grading of renogram curves and 22, 28, 23 and 25 by pathological scoring system. There was a significant correlation among the two score data (r = 0.867, p < 0.001).

Conclusions: (99m)Tc-MAG3 scintigraphy was a reliable method to evaluate renal dysfunction in the late period of I-R injury. Cyclic clamping, especially pedincular type was compatible with higher tubular dysfunction and structural damage.