Figure 1.

Renal functional parameters after 20 min of bilateral renal ischemia where the mice body temperature was maintained at normothermia (IR-37 °C) or mild therapeutic hypothermia (mTH) (IR-34 °C) and 2 h or 24 h of reperfusion, or after a Sham procedure with the same body temperature (Sham-37 °C and Sham-34 °C, or pooled as Sham). Renal function was assessed with plasma urea measured by a kinetic UV urease method after 2 h (a) or 24 h (b) of reperfusion. Renal ischemia-reperfusion induced acute kidney injury in IR-37 °C group at 2 h and 24 h, but mTH during ischemia (IR-34 °C group) attenuated this increase in plasma urea. (c) Renal acute tubular necrosis (ATN) was assessed at 24 h of reperfusion by a blinded pathologist. Histology scoring ranking from 0 to 4 was performed with: 0, no tubular injury; 1, less than 20% of tubules injured; 2, 21% to 50% tubules injured; 3, greater than 50% damage of tubule cells; 4, total destruction of all epithelial cells. mTH significantly lowered ATN score after ischemia-reperfusion, compared to normothermia. (d) Renal tissue apoptosis was assessed with TUNEL staining after 24 h of reperfusion. Renal ischemia-reperfusion induced a significant increase of cell apoptosis in the acute phase of reperfusion, that was reduced by mTH. (e) Representative images of 4-μm sections of kidney biopsy for each group, stained with periodic acid-Schiff reagents to assess acute tubular necrosis. Data are shown as median with interquartiles. * p < 0.05, ** p < 0.01, Mann–Whitney test. + p < 0.05, ++ p < 0.01 vs. Sham-37 °C, Mann–Whitney test. § p < 0.05 vs. Sham-34 °C, Mann–Whitney test.