Figure 4.

17β-Estradiol (E2) decreases intimal hyperplasia through its specific action on smooth muscle cells. A, mRNA levels from media, vastus lateralis muscle and heart from ovariectomized tamoxifen-injected αSMACreER^T2+ ERα^lox/lox vs αSMACreER^T2- ERα^lox/lox were measured by quantitative polymerase chain reaction and normalized to TPT1 expression. Results are expressed as mean±SEM. B, Four-week-old tamoxifen-injected αSMACreER^T2+ ERα^lox/lox and αSMACre-ER^T2- ERα^lox/lox female mice were ovariectomized and subcutaneously treated with placebo (control) or E2 until the end of the protocol. At 6 weeks, mice were submitted to mechanical injury of the femoral artery. Twenty-eight days later, mice were euthanized, and arteries were harvested for morphometric analysis. Representative images of cross sections of femoral arteries of indicated mice stained with Masson Trichrome. Bars, 100 µm. Quantitative analysis of neointima/media ratio of indicated mice. Values are mean±SEM (n=10–16 mice per group). As a statistical 2-way ANOVA revealed a significant interaction (P=0.04), it was followed by a Bonferroni post-test (***P<0.001).