Protective Effect of Alpha 1-Antitrypsin on Renal Ischemia-Reperfusion Injury

Background: α₁-Antitrypsin (AAT) is an important protein in the anti-inflammatory response that functions to regulate the activity of serine proteinases. We aimed to evaluate the protective effect of AAT on ischemia-reperfusion injury (IRI) in a mouse model. Methods: We investigated the effects of AAT in a C57BL/6 mouse model of IRI by dividing them into 4 groups: normal control, sham operated, ischemia-reperfusion (IR), and IR after AAT pretreatment (IR-AAT). In the IR-AAT group, mice were pretreated with AAT (80 mg/kg/d) for 3 days before renal ischemia was induced by clamping the bilateral renal vascular pedicles for 30 minutes. At 24 hours after IRI, biochemistry, histology, inflammatory cytokines, and apoptosis were assayed. Results: Blood urea nitrogen and serum creatinine levels were significantly lower in the IR-AAT group than in the IR group. Neutrophil gelatinase-associated lipocalin and kidney injury molecule 1 protein levels were significantly lower in the IR-AAT group than in the IR group. In addition, there were fewer tubular injuries and less interstitial fibrosis in the IR-AAT group than in the IR group, and the expression levels of transforming growth factor β, interleukin 1β, and interleukin 6 were significantly lower in the IR-AAT group than in the IR group. When compared with the IR group, there were fewer terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay–positive cells, lower caspase 3 activity and B-cell lymphoma 2-associated X protein (Bax), and higher B-cell lymphoma 2 (Bcl–2) in the IR-AAT group. Conclusions: α₁-Antitrypsin preserved renal function, attenuated tubular injuries and interstitial fibrosis, and inhibited inflammation and apoptosis after renal IRI. Our results suggest that AAT has protective effects against renal IRI by inhibiting inflammatory and apoptosis pathways.