Evaluation of kidney repair capacity using 99mTc-DMSA in ischemia/reperfusion injury models

Quantitative 99mTc-DMSA renal uptake was studied in different renal ischemia/reperfusion (I/R) mice models for the assessment of renal repair capacity. Mice models of nephrectomy, uni- and bi-lateral I/R together with sham-operated mice were established. At 1 h, 1 d, 4 d, 1, 2 and 3 wk after I/R, 99mTc-DMSA (27.7 ± 1.3 MBq) was injected via tail vein and after 3 h post-injection, the mice were scanned for 30 min with pinhole equipped gamma camera. Higher uptake of 99mTc-DMSA was measured in normal kidneys of uni-lateral I/R model and nephrectomized kidney I/R model at 3 wk post-surgery. Comparing the restoration capacities of the affected kidneys of nephrectomy, uni- and bi-lateral I/R models, higher repair capacity was observed in the nephrectomized model followed by bi-lateral then uni-lateral models. The normal kidney may retard the restoration of damaged kidney in uni-lateral I/R model. Moreover, 3 wk after Uni-I/R, the size of injured kidney was significantly smaller than non-ischemic contralateral and sham operated kidneys, while nephrectomy I/R kidneys were significantly enlarged compared to all others at 3 wk post-surgery. Very strong correlation between 99mTc-DMSA uptake and weight of dissected kidneys in I/R models was observed. Consistent with 99mTc-DMSA uptake results, all histological results indicate that kidney recovery after injury is correlated with the amount of intact tubules and kidney sizes. In summary, our study showed good potentials of 99mTc-DMSA scan as a promising non-invasive method for evaluation of kidney restoration after I/R injuries. Interestingly, mice with Bi-I/R injury showed faster repair capacity than those with uni-I/R.

Research highlights
► Quantitative 99mTc-DMSA renal uptake was studied in three renal ischemia/reperfusion (I/R) mice models for the assessment of renal repair capacity.
► 99mTc-DMSA scan was found to be a promising noninvasive method for evaluation of restoration status of damaged renal tubular cells.
► The 99mTc-DMSA uptake by renal tubular cells is directly correlated with degree of kidney damage as was confirmed by histological study.
► Comparing the restoration capacities of the affected kidneys, higher repair capacity was observed in the nephrectomized model followed by bi-lateral then uni-lateral models.