The effect and mechanism of an apolipoprotein E mimetic peptide ApoE23 on plasma lipopolysaccharide levels in the septic mice / 中华急诊医学杂志

ABSTRACT

Objective To observe the effect of apolipoprotein E mimetic peptide (ApoE23) on lipopolysaccharide (LPS) levels in plasma and the regulatory role of ApoE23 on low density lipoprotein receptor (LDLR) on liver cells in the septic mice.Methods An ApoE mimetic peptide was designed and referred terminologically as ApoE23 in abbreviation.ApoE23 was synthesized by using solid phase synthesis assay and were refined by using high performance liquid chromatography (HPLC).The peptide was identified and confirmed by using electron spray ionization mass spectrometry and amino acid composition analysis.The C57BL mice infected with Salmonella typhimurium group B were treated with apoE23 injected into tail vein.The plasma LPS levels were measured by using immunoturbidimetry.The LDLR expression and level on liver cells were measured by real time PCR and western blot respectively.Results The plasma LPS levels significantly increased and the liver LDLR expression decreased in the septic mice.ApoE23 treatment markedly reduced the plasma LPS levels and redressed the LDLR down-expressions on liver cells both in mRNA and protein levels compared to the septic mice without ApoE23 treatment.Conclusions The reduction of LPS level after ApoE23 treatment may be associated with the modulation role of ApoE23 in LDLR expression on liver cells,and ApoE23 may be a potential agent against bacterial sepsis as well.One of possible mechanisms was most likely associated with effect of ApoE23 on LDLR expression.