Abstract:
Background In the field of urology, nephron sparing surgery for localized renal tumors requires temporary clipping of the renal artery, resulting in renal ischemia. However, the duration of renal ischemia that will not lead to acute renal injury (AKI) is an urgent clinical problem to be solved.
Objective To explore the influence of different ischemia time on AKI in ischemia reperfusion injury (IRI) model, so as to provide evidence for the influence of ischemia time on kidney damage after nephron sparing surgery in urology.
Methods Fifteen male C57 mice at 8 weeks were selected and divided into 5 groups with 3 mice in each group according to different ischemia duration (0 min, 15 min, 25 min, 30 min and 45 min). The body temperature was kept constantly on the 37℃-38℃ constant temperature pads, then the left kidney IR + right kidney resection was performed. The operation time, preoperative weight and weight of right kidney of each mouse were recorded. The general state of the mice was closely observed and recorded postoperatively. The weight of the mice was recorded at 24 h after the operation. After anesthesia, blood was collected to detect serum creatinine and urea nitrogen, the left kidney was taken to measure the kidney weight, and the renal tissue was further examined by PAS staining.
Results The operation was successful. There was no statistically significance in the duration from skin incision to removal of the healthy right kidney, the duration from skin incision to clipping of the left kidney, preoperative weight, and the ratio of right kidney weight to preoperative weight among the 5 groups (P>0.05). After operation, the mice in 30 min and 45 min groups were in poor state, and the other three groups were in good condition. The creatinine, urea nitrogen, acute tubule necrosis scores, weight loss, kidney weight gain after ischemia, and the ratio of left kidney ischemia to postoperative weight were significantly higher in 30 min and 45 min ischemia groups than those in 0 min, 15 min and 25 min ischemia groups (P<0.05). After 30 min ischemia and 45 min ischemia, pathological PAS staining showed cortical renal tubule epithelial cells abscission and a large number of cells blocking renal tubules at the cortical medulla junction (P<0.05), and the postoperative creatinine (24 h), urea nitrogen, renal tubular pathological injury scores were significantly higher than those of the 0 min, 15 min, 25 min groups (P<0.05).
Conclusion The mouse unilateral renal ischemia-reperfusion AKI model has a narrow ischemia time window (critical point of ischemia) for inducing AKI. Under the condition of 37℃-38℃ warm ischemia, the critical point of ischemia time for unilateral renal IRI to lead to AKI is between 25-30 min. When it is less than 25 min, AKI does not occur, but it occurs when it is more than 30 min.
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