Aims
To investigate the potential inhibitory effect of Hydroxysafflor yellow A (HSYA) on myocardial fibrosis induced by isoproterenol (ISO) and angiotensin II (Ang II) and the possible underlying mechanism.
Conclusion
HSYA may inhibit myocardial fibrosis by blocking NLRP3 pathway in CFs.
Methods
Mice were injected subcutaneously with ISO and given HSYA by gavage in vivo. Masson's trichrome staining, immunohistochemical staining and immunofluorescence assays were conducted to evaluate the expression and localization of collagen and inflammatory cytokines, respectively. In vitro, cardiac fibroblasts (CFs) were treated with various doses of HSYA and induced with Ang II. Cell proliferation and migration were assessed using wound healing assay. Cell counting kit-8 was used to measure the cell viability. Collagen I, collagen III, phosphorylation of Smad2/3, Smad2/3, TGFβ1, interleukin (IL)-1β, IL-18, NLRP3 inflammasome-associated proteins were detected by Western blotting. Levels of reactive oxygen species (ROS) were evaluated using 2',7'-dichlorofluorescein diacetate assay.
Results
HSYA significantly inhibited ISO-induced myocardial fibrosis, NLRP3 inflammasome activation as well as IL-18 and IL-1β expressions in mice. HSYA significantly reduced the proliferation and migration of CFs, and suppressed the accumulation of collagen I and collagen III. TGFβ1 and P-Smad2/3 induced by Ang II was repressed by HSYA. HSYA downregulated IL-1β and IL-18, blocked NLRP3 activation, and reduced ROS in CFs.