Expression of microRNA-30e in sepsis-induced acute lung injury rats and its correlation with the levels of inflammatory cytokines

Abstract

Objective To investigate the differential expression of microRNA-30e in sepsis-induced acute lung injury(ALI)and its correlation with interleukin(IL)-1β and tumor necrosis factor(TNF)-α from two aspects of in vivo and in vitro. Methods Thirty SD male rats were randomly divided into 5 groups: normal control group, 3-hour sepsis group, 6-hour sepsis group, 12-hour sepsis group and 24-hour sepsis group in equal number.Sepsis-induced ALI model was induced by intraperitoneal injection of lipopolysaccharide(LPS, 10 mg/kg). The rat alveolar macrophages NR8383 were divided into blank control group and LPS(1 mg/L) stimulated 3, 6, 12, 24 hour groups.Inverse transcription-polymerase chain reaction was used to assay the production changes of IL-1β, TNF-α and miRNA-30e in lungs and cells.The injury of lung tissue was evaluated through histopathology. Results The levels of IL-1β and TNF-α in lung tissues of rats in sepsis groups were obviously up-regulated when compared with those in normal control groups(all P<0.01). The lung tissue hematoxylin-eosin staining indicated ALI in the sepsis group.The relative expression of miR-30e in rat lung tissue in sepsis 3, 6, 12, 24 hour groups were respectively 0.26±0.02, 0.41±0.08, 0.29±0.05 and 0.18±0.05, which were significantly lower than those in normal control group(1.23±0.24, all P<0.01). The levels of IL-1β and TNF-α in LPS stimulated NR8383 cells at different time points were obviously up-regulated when compared with those in blank control groups(all P<0.01). The relative expression of miR-30e in LPS stimulated 3, 6, 12, 24 hour groups were respectively 0.27±0.04, 0.55±0.05, 0.65±0.02 and 0.41±0.10, which were significantly lower than those in blank control group(1.17±0.21, all P<0.01). The expression of miR-30e in lung tissues of groups showed significantly negative correlations with those of IL-1β and TNF-α (IL-1β: r=-0.417, P=0.022; TNF-α: r=-0.437, P=0.016). The expression of miR-30e in LPS stimulated NR8383 cells of groups also showed significantly negative correlations with those of IL-1β and TNF-α (IL-1β : r=-0.713, P=0.003; TNF-α: r=-0.712, P=0.002). Conclusions The expression level of miR-30e was significantly down-regulated in sepsis-induced ALI, and had a significantly negative correlation with IL-1β and TNF-α, which may be used as a new biomarker of diagnostic, prognosis evaluation and therapy of sepsis-induced ALI. Key words: MicroRNA-30e; Sepsis; Lung injury, acute; NR8383; Inflammatory cytokines