COLLAGEN–ELASTIN IMBALANCE AND EXTRACELLULAR MATRIX REMODELING OF LEG ARTERIES IN EXPERIMENTAL METABOLIC SYNDROME

Abstract

The study aimed to characterize extracellular matrix (ECM) remodeling of the leg arteries in experimental metabolic syndrome (MS), focusing on the balance between the elastic and collagen components of the arterial wall. MS was induced in 90 sexually mature male white laboratory rats by a high-calorie diet combined with a 10% fructose solution as drinking water for 30, 60 and 90 days. The external iliac, femoral, popliteal, anterior and posterior tibial arteries were examined using hematoxylin–eosin and pentachrome staining with digital morphometry (NanoZoomer Hamamatsu, QuPath). As early as day 30, the volume fraction of elastic fibers decreased by 13.1–18.6% and the internal elastic lamina (IEL) became 8.3–15.2% thinner, while the collagen fiber fraction increased by 24.1–28.9%. By day 90, elastic fibers had decreased by 33.9–46.2% and IEL thickness by 24.1–38.8%, whereas collagen increased by 72.3–79.3% and adventitial thickness by 36.3–64.6%. Elastolytic and fibrotic changes were most pronounced in the distal (popliteal and tibial) segments. Collagen content correlated strongly and negatively with endothelial CD34 expression (r=−0.86) and positively with α-SMA expression (r=0.78). Progressive collagen–elastin imbalance is thus a key structural mechanism of peripheral arterial remodeling in MS.