Exploration of Analgesia with Tramadol in the Coxsackievirus B3 Myocarditis Mouse Model

Abstract

Infection of mice with Coxsackievirus B3 (CVB3) triggers inflammation of the heart and this mouse model is commonly used to investigate underlying mechanisms and therapeutic aspects for viral myocarditis. Virus-triggered cytotoxicity and the activity of infiltrating immune cells contribute to cardiac tissue injury. In addition to cardiac manifestation, CVB3 causes cell death and inflammation in the pancreas. The resulting pancreatitis represents a severe burden and under such experimental conditions, analgesics may be supportive to improve the animals’ well-being. Notably, several known mechanisms exist by which analgesics can interfere with the immune system and thereby compromise the feasibility of the model. We set up a study aiming to improve animal welfare while ensuring model integrity and investigated how tramadol, an opioid, affects virus-induced pathogenicity and immune response in the heart. Tramadol was administered seven days prior to a CVB3 infection in C57BL/6 mice and treatment was continued until the day of analysis. Tramadol had no effect on the virus titer or viral pathogenicity in the heart tissue and the inflammatory response, a hallmark of myocardial injury, was maintained. Our results show that tramadol exerts no disruptive effects on the CVB3 myocarditis mouse model and, therefore, the demonstrated protocol should be considered as a general analgesic strategy for CVB3 infection.

TF-FVIIa PAR2-β-Arrestin Signaling Sustains Organ Dysfunction in Coxsackievirus B3 Infection of Mice

“…Reported numbers were normalized for the utilized tissue weight, yielding the number of cells per milligram of tissue. For heart tissue, the following cell subsets were defined based on the gating procedure shown by Pinkert et al 43 : macrophages: CD45 + CD11b + B220 − CD3 − NK1.1 − Ly6G[1]CD11c +/− F4/80 + , inflammatory monocytes: CD45 + CD11b + B220 − CD3 − NK1.1 − Ly6G − CD11c − F4/80 − Ly6C hi , stationary monocytes: CD45 + CD11b + B220 − CD3 − NK1.1 − Ly6G − CD11c − F4/80 − Ly6C low , neutrophils: CD45 + CD11b + B220 − CD3 − NK1.1 − Ly6G + SSC hi , dendritic cells: CD45 + CD11b + B220 − CD3 − NK1.1 − Ly6G − CD11c + F4/80 − MHCII + , B cells: CD45 + CD11b − B220 + CD3 − , T cells: CD45 + CD11b − B220 − CD3 + .…”

Effect of TSS on anti-CVB3 through TLR3 pathway

“…The mice were killed, and heart tissue was taken and fixed in 10 % formaldehyde solution. After dehydration, washing, and embedding in paraffin to prepare pathological sections, the implanted hearts were cut into 5 μm sections and stained with hematoxylin and eosin (H&E) (5) .…”

“…In addition to direct virus-induced cardiac cytotoxicity, the immune system and host genetics play a central role in myocardial inflammation (4) . An immune response is necessary to control the virus, but inflammatory processes lead to cardiac damage and fibrotic remodeling (5) . Toll-like receptors (TLRs) are a class of innate immune recognition receptors that recognize molecular patterns associated with microorganisms and induce immune responses (6) .…”

ISG15 blocks cardiac glycolysis and ensures sufficient mitochondrial energy production during Coxsackievirus B3 infection

“… 5 , 6 Nevertheless, in recent work unrelated to the ISG15 field, we and others demonstrated that systemic pathology with haemodynamic compromise and weight loss during CVB3 infection is, if at all, only marginally attributable to viral cytotoxicity and inflammatory damage responses in heart tissue. 9 , 10 CVB3 infection of the heart induces small inflammatory foci, while the vast majority of cardiomyocytes, as well as systolic function of the ventricle, remain intact. 9 Therefore, it remains unclear if and to what extent the virus-suppressive activity of ISG15 attributes to maintained cardiac performance during CVB3 infection of mice.…”