精准医学杂志 (Apr 2024)
Effect of baicalein on fibrosis of myocardial tissue in EAM model mice
Abstract
Objective To explore the effect of baicalein on myocardial fibrosis in experimental autoimmune myocarditis (EAM) mice and its mechanism. Methods Twenty BalB/C mice were divided into blank group, EAM group, baicalein group, and dexamethasone group, with 5 mice in each group. On days 0 and 7, all the mice except those in the blank group were subcutaneously injected with 200 μL of complete Freund’s adjuvant and α-MyHC peptide emulsion. Starting from day 8, the mice in the EAM group, baicalein group, and dexamethasone group were intragastrically administered sodium carboxymethyl cellulose, baicalein, and dexamethasone, respectively. Echocardiography was performed on day 21 of administration to determine left ventricular ejection fraction (LVEF), shortening fraction (LVFS), left ventricular end-diastolic internal diameter (LVIDd), and left ventricular end-systolic internal diameter (LVIDs) in mice across all groups. On day 21, the mice from all groups were euthanized by cervical dislocation and their heart tissues were collected for HE staining and Masson staining. Flow cytometry was used to detect the proportion of Th17/Treg cells among the splenocytes. Real-time fluorescence quantitative PCR (RT-qPCR) and Western blot were used to analyze the mRNA and protein expression of Collagen Ⅰ, matrix metalloproteinase-1 (MMP-1), interleukin 17A (IL-17A), Treg transcription factor (FOXP3), and IL-10 in the cardiac tissue of mice. Results Echocardiographic results showed that the LVEF and LVFS of mice in baicalein group were significantly higher than those in the EAM group (F=51.55,35.38,q=8.08,5.97,P<0.05), while LVIDd and LVIDs were significantly lower than the EAM group (F=4.64,17.72,q=2.88,4.77,P<0.05). HE and Masson staining showed that infiltration of inflammatory cells and deposition of collagen fibers in the cardiac tissue of mice were significantly mitigated in the baicalein and dexamethasone groups as compared with the EAM group. Flow cytometry showed that the proportion of Th17/Treg cells was significantly higher in the EAM group than in the baicalein and dexamethasone groups (F=54.75,q=3.60,3.06,P<0.05). RT-qPCR showed that the mRNA levels of Collagen Ⅰ and IL-17A in the heart tissue of mice were significantly lower in the baicalein group than in the EAM group (F=112.40,77.49,q=14.57,8.27,P<0.05), while the mRNA levels of MMP-1, FOXP3, and IL-10 were significantly higher in the baicalein group than in the EAM group (F=19.05-144.60,q=5.37-11.21,P<0.05). Western blot showed that the expression of Collagen Ⅰ and IL-17A was significantly lower in the heart tissue of mice in the baicalein group than that in the EAM group (F=13.70,13.97,q=4.72,5.64,P<0.05), while the expression of MMP-1, FOXP3, and IL-10 was significantly higher in the baicalein group than in the EAM group (F=6.77-17.21,q=3.32-6.14,P<0.05). Conclusion Baicalein alleviates myocardial damage in EAM mice by regulating the balance between Th17/Treg in the spleen, thereby reducing the progression of myocardial tissue fibrosis.
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