Renal resistive index and biomarkers of cell cycle arrest in the early diagnosis of sepsis-induced acute kidney injury in rats

Objective: This study evaluates the diagnostic performance of renal resistive index (RRI) and urinary cell cycle arrest biomarkers for early detection of sepsis-induced acute kidney injury (AKI) in a rat model using cecal ligation and puncture (CLP). Materials and Methods: Sixty female Wistar Albino rats were allocated into six groups (n=10): five CLP groups based on measurement timing (3, 6, 12, 24, and 48 hours post-procedure) and one sham group. Following CLP, RRI measurements were performed, and blood, urine, and tissue samples were collected before sacrifice. Urinary tissue inhibitor of metalloproteinase-2 (TIMP-2) and insulin-like growth factor binding protein-7 (IGFBP-7) were quantified via enzyme-linked immunosorbent assay (ELISA). Serum creatinine and lactate levels were measured, and histopathological kidney examination was conducted. Results: RRI increased significantly at six hours (0.44±0.04), peaking at 24 hours (0.73±0.02) post-CLP. The [TIMP-2×IGFBP-7] combination elevated significantly at three hours (P0.45 demonstrated optimal diagnostic accuracy (sensitivity 89%, specificity 87%). Conclusions: In this CLP-induced polymicrobial sepsis model, both RRI and urinary cell cycle arrest biomarkers predicted early AKI within similar timeframes, with RRI >0.45 showing superior predictive value.