In the HCD group, H&E staining revealed marked intimal hyperplasia and pronounced regression of intimal hyperplasia after the acarbose treatment (Fig. 2a), and immunostaining for smooth muscle α-actin (α-SMA) and PCNA (Fig. 2b,c) showed significant and dose-dependent decreases in neointimal levels of these two markers after treatment with acarbose (2.5 and 5.0 mg kg−1). This evidence concerns the gene ACTA1 and heavy chain disease.