The Study Of Vitamin D In Experimental Autoimmune Myocarditisofmice

Part ⅠThe vitamin D concentration in serum correlated with cardiac function of autoimmune myocarditis or heart failure in miceAims:To obtain Experimental autoimmune myocarditis (EAM) or heart failure model by immunizing BALB/c mice with cardiac α-myosin heavy chain peptides (MyHC-α) and detect the vitamin D concentration in serum, and investigate the relationship between them.Methods:Six-eight-week-old male BALB/c mice were randomly divided into the following four groups:EAM group and its normal control group A, heart failure group and its normal control group B. Each mouse from EAM group was subcutaneously injected with 200 μl of emulsion (containing 200 g of MyHC-α peptide, dissolved in phosphate-buffered saline at a concentration of 2 mg/ml, and emulsified 1:1 with complete Freund’s adjuvant) on days 0 and 7 to induce EAM. The heart failure group mice were subcutaneously injected with 200 μl of emulsion on days 0, day 7 and day 30. All control group mice were treated with complete Freund’s adjuvant mixed with PBS,200 μl Mice from the control group A were treated on days 0 and 7 and control group B mice were treated on days 0, day 7 and day 30. Transthoracic echocardiography, hematoxylin and eosin (H&E), Masson staining and detection of vitamin D concentration in serum were performed on day 21 for mice from the EAM group and control group A, and on the 12th month for mice from the heart failure group and control group B.Results:Compared with their own control group, left ventricular internal dimensions at end-systole and end-diastole (LVEDs and LVEDd) were increased in mice from both EAM group and heart failure group, while left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were decreased (P<0.01). A large number of cells infiltrated in the heart of the EAM group, and obvious fibrosis occurred in the heart failure group. The concentration of vitamin D in serum were decreased in both EAM group and heart failure group (P<0.05). Moreover, the Spearman’s correlation analysis showed that there was a significantly positive correlation between vitamin D concentration and LVEF, LVFS from both EAM group and heart failure group (r=0.75, P<0.05; r=0.75, P<0.05; r= 0.738, P<0.05; r=0.714, P<0.05). Additionally, a significant negative correlation between vitamin D concentrations and LVEDs in the EAM group(r=-0.717, P=0.030), and LVEDd in the heart failure group (r=-0.810, P=0.015).Conclusion:Experimental autoimmune myocarditis and heart failure were successfully achieved by immunizing BALB/c mice with cardiac a-myosin heavy chain peptides. Vitamin D concentration decreased in both the EAM group and heart failure group, and it correlated with LVEF, LVFS, LVEDs or LVEDd in both groups.Part ⅡEffects of 1,25-Dihydroxyvitamin D3 on experimental autoimmune myocarditis in miceBackground/Aims:Myocarditis is an important inflammatory disease of the heart.1, 25(OH)2 D3 has effects on multiple systems and diseases. The present study was aimed to investigate the effect of 1,25(OH)2 D3 on experimental autoimmune myocarditis (EAM), and explored the underlying mechanisms involved.Methods:EAM was induced by immunizing BALB/c mice with cardiac a-myosin heavy chain peptides (MyHC-α).1,25(OH)2 D3 (1,000 ng/kg once) or vehicle was administered intraperitoneally every other day during the entire experiment. On day 21, transthoracic echocardiography was performed and cardiac inflammatory infiltration was detected by hematoxylin and eosin (HE). The terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling (TUNEL) assay, and Western blots for the expression of protein caspase-3 and cleaved-caspase3 were used to evaluate apoptosis. Transmission electron microscopy and Western blots for the expression of protein Beclinl, LC3B, and P62 were used to evaluate autophagy.Results:The ratio of heart weight/body weight was significantly reduced in 1,25(OH)2 D3-treated EAM mice, compared with vehicle-treated ones.1,25(OH)2 D3 treatment improved cardiac function, diminished cell infiltration in cardiac, suppressed myocardial apoptosis, inhibited Beclin 1 over-activation, decreased the number of autophagosomes, and decreased LC3-II and p62 protein expression.Conclusions:The present results demonstrated that administration of 1,25(OH)2 D3 decreased EAM severity.1,25(OH)2 D3 treatment may be a feasible therapeutic approach for EAM.