Dihydromyricetin improving myocardial function in the mice induced by CCl4.

Objective: To study the role and underlying mechanisms of dihydromyricetin on the myocardial function in mice induced by CCl₄.

Methods: Eighteen C57BL/6 mice (6-8 W, female) were randomly divided into the following three groups: control group, CCl₄-induced positive group (CCl₄ group), dihydromyricetin group, six mice/group. NLRP3-deficient (NLRP3^-/-) C57BL/6 mice used the same age, gender, and modeling method. The HL-1 cells were used for in vitro experiments. The HL-1 cells were treated with PBS, CCl₄, and CCl₄ + DMY respectively.

Results: The RT-qPCR results showed that compared to the mice induced by CCl₄, the dihydromyricetin increased the Arg-1 mRNA level in the mouse myocardial tissues. The mRNA expressions of the iNOS, IL-33, and ST2 were reduced by the dihydromyricetin. The results of immunohistochemistry showed that dihydromyricetin decreased IL-33 protein expressions in the myocardial tissues. Western blot results also showed that compared with the control group, the activation of NLRP3 inflammasomes in the myocardial tissues of mice injured by CCl₄ was increased, and dihydromyricetin can reduce NLRP3 inflammasomes activation in the myocardial tissues induced by CCl₄. The results of ELISA showed that dihydromyricetin could reduce the IL-1β level in the serum of the mice induced by CCl_4. Consistent with the in vivo results, compared with the control group, the NLRP3 inflammasome activation and IL-33/ST2 expression were increased in the CCl₄-treated HL-1 cells, while DMY significantly weakened this effect. Interestingly, NLRP3 deficiency enhanced the protective effect of DMY on myocardial function in mice.

Conclusions: IL-33/ST2 signaling pathways and NLRP3 inflammasome activation may be involved in dihydromyricetin improving the myocardial function of the mice induced by CCl₄.