COL1A1 and Myocardial fibrosis: For myocardial fibrosis genes, the mRNA expression of Col1a1 was significantly higher in the HH group, the mRNA expression of Act1 and Atp2a2 was also significantly higher in the HN and HH groups (p < 0.05), while the mRNA expression of Tgf-β1 was not significantly different among the groups (p > 0.05).