Alpha-lipoic acid exerts anti-inflammatory effects on lipopolysaccharide-stimulated rat mesangial cells via inhibition of nuclear factor kappa B (NF-κB) signaling pathway.

Abstract

Sepsis is often initiated by invasive infection, characterized by overwhelming induction of pro-inflammatory cytokines. The incidence and mortality of sepsis and the associated development of acute kidney injury (AKI) remain high, and lines of research into potential treatments are needed. This study was conducted to investigate effects of alpha-lipoic acid (ALA) on septic AKI in vitro. ALA of 200 or 400 μM was used to pretreat rat HBZY-1 mesangial cells before commencement of 1 μg/mL lipopolysaccharide (LPS). Our data indicated that ALA pretreatment reduced LPS-stimulated release of inflammatory cytokines, such as tumor necrosis factor alpha (TNF-α), interleukin (IL)-1 beta (IL-1β), as well as IL-6, in HBZY-1 cell supernatant. Moreover, LPS-induced expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) was inhibited by ALA pretreatment, and consequently, the secretion levels of their respective enzymatic products prostaglandin E2 (PGE2) and nitric oxide (NO) were significantly decreased. LPS-enhanced phosphorylation of nuclear factor kappa B (NF-κB) inhibitor alpha (IκBα) and IκB kinase alpha/beta (IKKα/β) and nuclear translocation of NF-κB subunit p65 in HBZY-1 cells were inhibited by ALA pretreatment. Additionally, the NF-κB inhibitor N-acetylcysteine (NAC) exerted similar inhibitory effects as ALA on COX-2 and iNOS expression. In summary, our study demonstrates that ALA mitigates LPS-induced inflammatory responses in rat mesangial cells probably via inhibition of NF-κB signaling pathway, suggesting a therapeutic potential of ALA in AKI related to sepsis.