*3.3. Treatment Effects on Cardiac Remodeling and Fibrosis*

#### 3.3.1. mRNA Expression of Collagens I and III

With transition to fibrosis, expression of collagen mRNA can be observed. In untreated ySHRs, the mRNA expression of Coll 1 and Coll 3 was 13.9 ± 2.1 and 22.5 ± 1.9, respectively. Treatment had no significant effect; the mRNA expression of the two collagens was even slightly increased to 15.4 ± 3.4 and 23.4 ± 3.7, respectively.

In 82-week-old untreated SHRs, mRNA expression of Coll 1 and Coll 3 was in a similar range, with 15.9 ± 4.6 and 25.4 ± 4.2, respectively. However, 22 weeks of treatment significantly reduced the collagen mRNA expressions to 4.1 ± 0.8 (Coll 1; *p* = 0.007) and 9.4 ± 1.5 (Coll 3; *p* < 0.001). The treatment effects were significantly higher than in young animals (Coll 1: 74.5 ± 5.2%, *p* = 0.003; Coll 3: 63.1 ± 6.0%, *p* = 0.001; Figure 4).
