Apigenin attenuates heart injury in lipopolysaccharide-induced endotoxemic model by suppressing sphingosine kinase 1/sphingosine 1-phosphate signaling pathway

Sepsis is a cluster of heterogeneous syndromes associated with progressive endotoxemic developments, ultimately leading to damage of multiple organs, including the heart. This study is to investigate the effects of apigenin on heart injury in lipopolysaccharide-induced endotoxemic rat model. Normal Wistar rats were randomly divided into four groups: control group, LPS group (15 mg/kg), LPS plus apigenin groups with different apigenin doses (50 mg/kg, 100 mg/kg). Serum levels of creatine kinase (CK), lactate dehydrogenase (LDH), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β) were measured after the rats were sacrificed. SphK1/S1P signaling pathway proteins, cleaved caspase-3, cleaved caspase-9, Bax and Bcl-2 in heart were measured by Western blot. In vitro, we evaluated the protective effect of apigenin on rat embryonic heart-derived myogenic cell line H9c2 induced by LPS. Apigenin decreased serum levels of CK-MB, LDH, TNF-α, IL-6, IL-1β. SphK1/S1P signaling pathway proteins, cleaved caspase-3, cleaved caspase-9, Bax in heart were found inhibited and Bcl-2 increased in the apigenin groups in vivo. In addition, apigenin inhibited intracellular calcium, the MAPK pathway and SphK1/S1P signaling pathway in vitro. Apigenin exerts pronounced cardioprotection in rats subjected to LPS likely through suppressing myocardial apoptosis and inflammation by inhibiting the SphK1/S1P signaling pathway.