Necrostatin-1 attenuates sepsis-associated acute kidney injury by promoting autophagosome elimination in renal tubular epithelial cells.

Abstract

The aim of the present study was to investigate the protective effect of necrostatin‑1 (Nec‑1) in sepsis‑associated acute kidney injury (SA‑AKI). An SA‑AKI mouse model was established through an intraperitoneal injection of lipopolysaccharide (LPS), and Nec‑1 was administered to the mice prior to the establishment of SA‑AKI. Renal function and histological changes were evaluated, and the expression levels of microtubule‑associated protein light chain 3‑II (LC3‑II) and p62, as markers of autophagic flux, were detected. Autophagosomes and autolysosomes in renal tubular epithelial cells were also identified using electron microscopy. Pretreatment with Nec‑1 could attenuate the LPS‑induced increases in the concentrations of blood urea nitrogen (LPS+Nec‑1 vs. LPS group, 14.15±4.14mmol/l vs. 32.54±5.46mmol/l, respectively; P<0.001) and serum creatinine (11.50±1.67µmol/l vs. 30.08±4.18µmol/l, respectively; P<0.001). However, there were no significant differences in the rate of renal tubular epithelial cell necrosis between the groups. In the renal tissues of SA‑AKI mice, protein analysis showed that the LC3‑II and p62 proteins were increased, while a reverse transcription‑quantitative Reverse transcription‑polymerase chain reaction analysis detected no increase in LC3‑II or p62 mRNA. Additionally, a high number of autophagosomes, but not of autolysosomes, were observed by electron microscopy. When mice were pretreated with Nec‑1, the levels of LC3‑II and p62 decreased, and a large number of autolysosomes were observed by electron microscopy in the Nec‑1 pretreatment group. These results indicated that Nec‑1 improved autophagosome elimination, a process that is impaired by LPS, in renal tubular epithelial cells. This potentially enabled Nec‑1 to prevent SA‑AKI. Furthermore, the findings suggested that the protective effect of Nec‑1 may not have involved the inhibition of necroptosis, but may have occurred through the promotion of autophagosome elimination in renal tubular epithelial cells.