Biomolecular Changes in the Myocardium of Female and Male BALB/c Mice with Autoimmune Myocarditis

Autoimmune myocarditis is a disease with pronounced sex-related differences. It is known that the incidence of myocarditis is higher in men; however, other autoimmune diseases are more commonly observed in women. The aim of this study was to assess molecular and biological changes in the myocardium of male and female BALB/c mice on days 14 and 60 of experimental autoimmune myocarditis. We examined the morphological properties of the myocardium, the expression of pro- and anti-inflammatory markers in the myocardium, and the concentrations of IL-1β and IL-10 in blood serum. Sex-specific differences in the molecular and biological changes in the myocardium were identified at both time points of autoimmune myocarditis. In males, a pronounced lymphoid-histiocytic infiltration was observed, along with alterations in the balance of pro- and anti-inflammatory cytokines. Males showed increased expression of Il1b, Il6, Hif1a, and Tgfb mRNA on day 14 and Il1b, Nfkb, Il10, and Tgfb mRNA on day 60. In females, changes were less pronounced: the expression of Il1b mRNA was elevated on day 14, but no significant changes were observed on day 60. The serum levels of IL-10 and IL-1β in males increased on days 14 and 60, respectively. These findings may explain the sex-specific differences in the course of autoimmune myocarditis.