Cardioprotection And Mechanism Of Embelin In Mice With LPS

Background:In the past 20 years, incidence of sepsis has been increasing year by year. And the mortality of sepsis has been reached over 50%. The pathophysiological mechanisms of sepsis-induced organ failure is not yet clear. Reduce the mortality has become a major difficult problem in critical care. Patients with sepsis are usually accompanied by cardiac dysfunction, which might increase the mortality. Embelin is the main component of Embelia ribes. Recently, more and more studies have shown that embelin has antioxidant, hepatic protection, anti-diabetic, anti-bacterial, anti-cancer effects, and also has anti-inflammatory effects in a variety of organs.Objectives:The aims of the present study were to observe the effect of embelin on the cardiac injury in sepsis mice model, to explore whether PPARy is participate in the cardioprotection of embelin, and to investigate the role of NF-kB、TNF-αMethods1. Animal groupsMale 57BL/6J (B6) mice were randomly divided into five groups (n=17). Control group:Mice were received PBS i.p. injection. Sepsis model group:Mice were received LPS (10 mg/kg) i.p. injection. Embelin treatment groups:Mice were received LPS (10 mg/kg) i.p. injection, after 30 min different doses of embelin were given (5,10, and 20 mg/kg, i.p.).2. Measurement of cardiac troponin IBlood was collected from the orbital cavity of mice. After centrifuged, serum was separated. Serum cardiac troponin I (cTnl) content was measured using two-site enzyme immunoassay.3. Detection of PPAR-y and TNF-α protein by immunohistochemistry method Left ventricular tissue was fixed 10% neutral formalin. After conventional embedded, sliced, dehydrated, blocked with BSA, the slices were incubated with PPAR-y or TNF-a primary antibody (rabbit IgG, dilution of 1:100) overnight. Then the slices were incubated with HRP-labelled anti-rabbit IgG, and colourated with DAB.4 Evaluation of nuclear NF-κB protein by using western blotting method The left ventricular tissue was isolated and homogenized in nuclear protein extraction buffer. The extracted protein was separated by SDS-PAGE. After transferred to NC membrane, the protein was detected by NF-κB antibody (1:1000) or nuclear internal Histone H3, and visualized by using ECL method.Results1. Effect of the embelin on the cardiac injury in sepsis miceCompared with control group, the serum cTnl level was higher in sepsis mice (5.15±0.25 ng/ml, vs control 0.11±0.02 ng/ml). The serum cTnI level in low dose embelin (5 mg/kg) treatment mice was not different with that of the sepsis mice. But the serum cTnI level in middle and high doses embelin (10,20 mg/kg) treatment mice was much higher than that of sepsis mice (respectively 3.96±0.33 ng/ml and 2.51±0.19ng/ml).3. Effect of embelin on the morphology in sepsis miceHE staining results showed that the myofilament morphology was normal and clear with uniform color in the control group mice. Myofilament rupture and disordered structure were obviously observed in the heart of sepsis mice, which were prevented with the treatment of embelin (10,20 mg/kg).3. Effect of embelin on the PPAR-y expression of sepsis miceThe expression of PPAR-y protein in mice heart was no significant different between the control group and sepsis group, compared with the control and sepsis groups, the embelin (10,20 mg/kg) treatment increased the PPAR-y expression.3. Effect of embelin on the TNF-a protein and nuclear NF-κB proteinIn control group, TNF-a protein and nuclear NF-κB protein expression were weak. TNF-a protein and nuclear NF-κB protein expression were significantly increased in the mice treated with LPS. However, the embelin (10,20 mg/kg) could partly inhibit the LPS-induced the enhancement of TNF-a protein and nuclear NF-κB protein expression.ConclusionEmbelin could protect against sepsis-induced cardiac injury. The mechanism might be involved in the upregulation of PPARy protein, inhibition of NF-κB activation, and reduction of TNF-a level.