Related Experiment Video
Updated: May 22, 2026
A Reproducible Intensive Care Unit-Oriented Endotoxin Model in Rats
Published on: February 20, 2021
Toll-like receptor 3 plays a central role in cardiac dysfunction during polymicrobial sepsis
Ming Gao1, Tuanzhu Ha, Xia Zhang
1Department of Surgery, Internal Medicine, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.
Insights
Toll-like receptor 3 (TLR3) exacerbates cardiac dysfunction and mortality in polymicrobial sepsis. Blocking TLR3 activity protected mice from sepsis-induced heart damage and improved survival rates, suggesting TLR3 as a therapeutic target.
Area of Science:
- Immunology
- Cardiovascular Biology
- Sepsis Pathophysiology
Background:
- Myocardial dysfunction is a critical factor in septic shock mortality.
- Toll-like receptors (TLRs) are key mediators in sepsis pathogenesis.
- TLR3 recognizes double-stranded RNA and is implicated in inflammatory responses.
Purpose of the Study:
- To investigate the specific role of Toll-like receptor 3 (TLR3) in the development of cardiac dysfunction during polymicrobial sepsis.
- To assess the impact of TLR3 deficiency on cardiac function, survival, and inflammatory signaling pathways in a sepsis model.
Main Methods:
- A controlled animal study using male C57BL/6 wild-type and Toll-like receptor 3 knockout (TLR3-/-) mice.
- Polymicrobial sepsis was induced via cecal ligation and puncture (CLP).
- Cardiac function was evaluated using echocardiography; survival and myocardial inflammatory markers were assessed.
Main Results:
- Cecal ligation and puncture (CLP) induced significant cardiac dysfunction in wild-type mice.
- TLR3 knockout mice maintained cardiac function and exhibited significantly improved survival rates compared to wild-type controls.
- TLR3 deficiency attenuated cardiac myocyte apoptosis, reduced inflammatory mediator expression, and inhibited TLR4-mediated signaling pathways.
Conclusions:
- Toll-like receptor 3 (TLR3) plays a detrimental role in sepsis-induced cardiac dysfunction.
- Targeting TLR3 activity presents a potential therapeutic strategy for preventing cardiac complications in sepsis.
Objective:
To determine the role of Toll-like receptor 3 in cardiac dysfunction during polymicrobial sepsis.
Design:
Controlled animal study.
Setting:
University research laboratory.
Subjects:
Male C57BL/6, wild-type, Toll-like receptor 3-/-.
Intervention:
Myocardial dysfunction is a major consequence of septic shock and contributes to the high mortality of sepsis. Toll-like receptors (TLRs) play a critical role in the pathophysiology of sepsis/septic shock. TLR3 is located in intracellular endosomes, and recognizes double-stranded RNA. This study examined the role of TLR3 in cardiac dysfunction following cecal ligation and puncture (CLP)-induced sepsis. TLR3 knockout (TLR3-/-, n=12) and age-matched wild-type (n=12) mice were subjected to CLP. Cardiac function was measured by echocardiography before and 6 hrs after CLP.
Measurements And Main Results:
CLP resulted in significant cardiac dysfunction as evidenced by decreased ejection fraction by 25.7% and fractional shortening by 29.8%, respectively. However, TLR3-/- mice showed a maintenance of cardiac function at pre-CLP levels. Wild-type mice showed 50% mortality at 58 hrs and 100% mortality at 154 hrs after CLP. In striking contrast, 70% of TLR3-/- mice survived indefinitely, that is, >200 hrs. TLR3 deficiency significantly decreased CLP-induced cardiac-myocyte apoptosis and attenuated CLP-induced Fas and Fas ligand expression in the myocardium. CLP-activation of TLR4-mediated nuclear factor-κB and Toll/IL-1 receptor-domain-containing adapter-inducing interferon-β-dependant interferon signaling pathways was prevented by TLR3 deficiency. In addition, CLP-increased vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 expression, and neutrophil and macrophage sequestration in the myocardium were also attenuated in septic TLR3-/- mice. More significantly, adoptive transfer of wild-type bone-marrow stromal cells to TLR3-/- mice abolished the cardioprotective effect in sepsis.
Conclusions:
These data indicate that TLR3 plays a deleterious role in mediating cardiac dysfunction in sepsis. Thus, modulation of the TLR3 activity may be useful in preventing cardiac dysfunction in sepsis.
More Related Videos
Related Concept Videos
01:14Myocarditis III: Medical Management
01:23Rheumatic Heart Disease I: Introduction
01:18Endocarditis III: Medical Management
01:25Inflammatory Bowel Disease III: Crohn's Disease
01:21Myocarditis I: Introduction
01:25Acute Inflammation III: Local and Systemic Effects