2.1. Animals and treatment

A total of 8‐10 weeks old C57/B6J mice (male; 23.5‐27.5 g) were purchased from the Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences (Beijing, China), kept in a quarantine room for a week to adapt to the environment. All mice were housed under specific environmentally controlled (temperature: 20‐25 °C; Humidity: 50 ± 5%) barrier conditions and fed on rodent diet ad libitum. Furthermore, cardiomyocyte‐specific TLR7 overexpression (TLR7‐cTG, bought from the Jackson Laboratory) and TLR7 knockout (TLR7^−/−, C57/B6J background, bought from the Jackson Laboratory) mice were utilized in this study as well. The detail of genetic background and generation of TLR7^−/− and TLR7‐cTG mice is provided in the online supplementary material.

Mice aged 10 weeks (23.5‐27.5 g) were randomly assigned into four groups: NS‐WT group (n = 12), NS‐TLR7^−/− group (n = 12), lipopolysaccharide (LPS)‐WT group (n = 20), and LPS‐TLR7^−/− group (n = 20). Mice in each group underwent an intraperitoneal injection of LPS (Sigma,10 mg/kg) or saline equally. Furthermore, 10 weeks old TLR7‐cTG and LWT mice (23.5‐27.5g) were randomly divided into four groups: NS‐LWT group (n = 12), NS‐cTG‐TLR7 group (n = 12), LPS‐LWT group (n = 20), and LPS‐cTG‐TLR7 group (n = 20). Mice in each group were injected intraperitoneally with LPS (10 mg/kg) or saline. Additional details are provided in the supplementary material online.