Therapeutic efficacy of Schistosoma japonicum cystatin on sepsis-induced cardiomyopathy in a mouse model

Abstract

Background Myocardial dysfunction is one of the most common complications of multiple organ failure in septic shock and significantly increases mortality in patients with sepsis. In spite of many studies have confirmed that helminth-derived proteins have strong immunomodulatory functions and could be used to treat inflammatory diseases, there is no report on the therapeutic effect of Schistosoma japonicum -produced cystatin ( Sj- Cys) on the sepsis-induced cardiac dysfunction. Methods A model of sepsis-induced myocardial injury was established by cecal ligation and puncture (CLP) in mouse. Upon CLP operation, each mouse was intraperitoneally treated with 10 µg of recombinant Sj -Cys (r Sj -Cys). Twelve hours after CLP operation, the systolic and diastolic functions of left ventricular were examined by echocardiography. The levels of myoglobin (Mb), cardiac troponin I (cTnI), N-terminal pro-Brain Natriuretic peptide (NT-proBNP) in sera and the activity of myeloperoxidase (MPO) in cardiac tissues were examined as biomarkers for heart injury. The heart tissue was collected for checking pathological changes, macrophages and pro-inflammatory cytokine levels. To address the signaling pathway involved in the anti-inflammatory effects of r Sj -Cys, myeloid differentiation factor 88 (MyD88) was determined by Western blot in heart tissue of mice with sepsis and LPS-stimulated H9C2 cardiomyocyte cells. In addition, the therapeutic effects of r Sj -Cys on LPS-induced cardiomyocyte apoptosis were also detected in H9C2 cells.The levels of M1 biomarker iNOS and M2 biomarker Arg-1 were detected in heart tissue. The pro-inflammatory cytokines TNF-α and IL-6 and regulatory cytokines IL-10 and TGF-β were measured in sera and their mRNA levels in heart tissue of r Sj -Cys-treated mice. Results After being treated with r Sj -Cys, the sepsis-induced heart malfunction was largely improved. The inflammation and injury of heart tissue were also significantly alleviated characterized as significantly decreased infiltration of inflammatory cells in cardiac tissues and fiber swelling, reduced levels of Mb, cTnI and NT-proBNP in sera and MPO activity in heart tissue. The therapeutic efficacy of r Sj -Cys is associated with down-regulated pro-inflammatory cytokines (TNF-α, IL-6) , as well as the decreased M1 macrophages and increased M2 macrophages, possibly through inhibiting LPS-MyD88 signal pathway. Conclusions Recombinant Sj -Cys significantly reduced sepsis-induced cardiomyopathy and could be considered as be a potential therapeutic agent for the prevention and treatment of sepsis associated cardiac dysfunction.