Evaluating the Recovery Process of Renal Ischemia/Reperfusion Injury in Rats Using Small-Animal SPECT

Background: Renal injuries associated with ischemia/reperfusion are a prevalent clinical phenomenon that can cause the emergence of progressive kidney diseases, eventually leading to chronic kidney injuries. The present study was conducted to evaluate the results obtained from non-invasive imaging using small-animal SPECT and investigate the recovery process in an animal model of renal ischemia/reperfusion. Materials and Methods: Male Wistar rats were used to establish a unilateral model of renal ischemia/ reperfusion injury. After occluding the left renal pedicle for 120 minutes, the animals were investigated in terms of reperfusion at 24 hours, one week and three weeks. At each time point, the intravascular injection of 99mTc-DMSA as well as scanning with the SPECT machine were conducted. Blood sampling and renal biopsy were also performed. Results: After 24 hours, the accumulated activity levels were significantly lower in the ischemic kidney compared to in the contralateral intact kidney. Severe renal histologic changes were also observed. After one and three weeks, the radiopharmaceutical uptake increased in the ischemic compared to both the contralateral kidney and the time point of 24 hours, and the absorbed activity was divided between the two kidneys in a more balanced fashion, which is quite consistent with the histologic results. Conclusion: The present findings suggest that non-invasive imaging with a small-animal SPECT system using 99mTc-DMSA provides researchers with an appropriate tool in rodent models of renal ischemic damage for evaluating the long-term follow-up of kidney recovery. The obtained results also appear to be thoroughly consistent with invasive histological studies.