Abstract
Sepsis remains a worldwide public health problem. This study aims to explore the role and mechanism of transcriptional factors (TFs) in sepsis-induced myocardial injury. Firstly, TF KLF13 was selected to explore its role in sepsis-induced myocardial injury. The caecal ligation and puncture (CLP) -induced sepsis mouse model was established and the septic mice were examined using standard histopathological methods. KLF13 expression was detected in the septic mouse heart and was also seen in a lipoploysaccharide (LPS) -induced cellular inflammation model. To explore this further both pro-apoptotic cleaved-caspase3/caspase3 and Bax levels and anti-apoptotic Bcl2 levels were examined, also in both models, In addition inflammatory cytokine (IL-1β, TNF-α, IL-8 and MCP-1) production and IκB-α protein level and p65 phosphorylation were examined in both septic mice and LPS-induced cells. Thus three parameters - cardiomyocyte apoptosis, inflammatory response and NF-κB pathway activation were evaluated under similar conditions. The septic mice showed significant oedema, disordered myofilament arrangement and degradation and necrosis to varying degrees in the myocardial cells. KLF13 was downregulated in both the septic mouse heart and the LPS-induced cellular inflammation model. Furthermore, both models showed abnormally increased cardiomyocyte apoptosis (increased cleaved-caspase3/caspase and Bax protein levels and decreased Bcl2 level), elevated inflammation (increased production of inflammatory cytokines) and the activated NF-κB pathway (increased p65 phosphorylation and decreased IκB-α protein level). KLF13 overexpression notably ameliorated sepsis-induced myocardial injury in vivo and in vitro. KLF13 overexpression protected against sepsis-induced myocardial injury and LPS-induced cellular inflammation and apoptosis via inhibiting the inflammatory pathways (especially NF-κB signalling) and cardiomyocyte apoptosis.