Effects of immunosuppressive drugs on rat renal ischemia reperfusion injury

Recent evidence has demonstrated that the immune response and, more specifically, lymphocytes (T and B) and dendritic cells participate as mediators of renal ischemia reperfusion injury (IRI). The aim of this study was, therefore, to evaluate the effect of various immunosuppressive drugs with known activity to prevent IRI among rats undergoing a scheme that is potentially applicable in the clinic.

Male Sprague-Dawley rats (200-300 g) underwent 60 minutes of ischemia by renal artery clamping and contralateral nephrectomy. The experimental groups (n = 6-7) were as follows: I, Sham; II, Control; III, Rapamycin (R; 1 mg/kg); IV, Methylprednisolone (M; 15 mg/kg); V, Vitamin D3 (VD3; 2 microg/kg); VI, VD3 (1 microg/kg); and VII, M (15 mg/kg) + R (1 mg/kg). Each drug was administered in 2 doses at 6 hours and 1 hour before surgery. Creatinine (Cr) was determined on days 0.1, 2, 3, 5, and 7, and Cr clearance was determined on days 3 and 7. At 7 days nephrectomy was performed to obtain samples for histology to evaluate the degree of acute tubular necrosis.

Mortality from renal insufficiency was between 0 and 33%, except in group V (66%; 4/6; P = .01). Kidney function was similar to controls in all groups except for creatinine at 7 days between group VI (VD3) and control (1.05 vs 0.65; P < .05) but no difference in Cr clearance. Histologically moderate to severe renal damage was greater in groups V and VI (VD3) than controls (P = .04).

We observed that none of the drugs conferred protection against IRI in a time setting relevant to kidney transplantation. Controversy exists regarding R, because some prior studies have shown a deleterious effect on IRI injury, although we did not observe any deleterious effect.