Résumé
Hypothyroidism alone can lead to myocardial fibrosis and result in heart failure, but traditional hormone replacement therapy does not improve the fibrotic situation. Hydrogen sulfide (H 2 S), a new gas signaling molecule, possesses antiinflammatory, antioxidant, and anti-fibrotic capabilities. Whether H 2 S could improve hypothyroidism-induced myocardial fibrosis are not yet studied. In our study, H 2 S could decrease collagen deposition in the myocardial tissue of rats caused by hypothyroidism. Furthermore, in hypothyroidism-induced rats, we found that H 2 S could enhance cystathionine-gamma-lyase (CSE), not cystathionine β-synthase (CBS), protein expressions. Finally, we noticed that H 2 S could elevate autophagy levels and inhibit the transforming growth factor-β1 (TGF-β1) signal transduction pathway. In conclusion, our experiments not only suggest that H 2 S could alleviate hypothyroidism-induced myocardial fibrosis by activating autophagy and suppressing TGF-β1/ SMAD family member 2 (Smad 2) signal transduction pathway, but also show that it can be used as a complementary treatment to conventional hormone therapy.
Résumé
Objective:To observe the effects of Shexiang Baoxin Pill (SBP) on isoprenaline (Iso)-induced changes in myocardial cell volume,shape,and connexin 43 (Cx43) expression.Methods:HgC2 myocardial cells were randomly divided into a control group,a Iso group and a Iso+SBP group.After 72 h of culture,the average surface area of HgC2 cells was measured under phase contrast microscope.Bicinchoninic acid (BCA) protein assay was carried out to determine the concentration of proteins.The survival rate of myocardial cells was measured by methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay,and the Cx43 expression was detected by Western blot.Results:The mean surface area and Cx43 concentration in Iso-treated myocardial cells were increased under the phase contrast microscope (P<0.05).Compared with the Iso group,the mean surface area was decreased,and the Cx43 concentration was reduced in the Iso+SBP group (both P<0.05).Compared with the control group,the Cx43 expression was obviously down-regulated in the H9C2 cells of the Iso group (P<0.05);while compared with the Iso group,the Cx43 expression was obviously up-regulated in the Iso+SBP group (P<0.05).Conclusion:Shexiang Baoxin Pills can prevent Iso-induced myocardial hypertrophy and down-regulate Cx43 expression.