The purpose of this study was to gain knowledge about the micromorphology of the porcine common carotid artery (CCA) during the period of growth over the bodyweight range of 10–40 kg. CCA samples from German landrace pigs (DL) aged either 2 or 3 months (DL‐2 and DL‐3) were compared with samples from Göttingen minipigs (GM) aged either 18 or 40 months (GM‐18 and GM‐40) using transmitted light (phase‐contrast mode) and transmission electron microscopy. The GM‐18, GM‐40 and the DL‐3 groups had typical muscular artery histological characteristics. Contrasting to this, the 2‐month‐old DL pigs had a transitional artery type being characterized by a significantly higher proportion of elastic fibres and a significantly lower number of smooth muscle cells than did the 1 month older DL‐3. During the period of maturation, the tunica media of the CCA in GM animals thickened by 1.3× and in DL animals by 2.5× resulting in an overall increased vessel wall thickness. The cumulated thickness of the tunica interna (endothelium, stratum subendotheliale and internal elastic lamina) and the tunica media (including the external elastic lamina) of DL‐3 and GM‐40 pigs were similar to each other and comparable to that of humans. With an increasing vessel wall thickness, the luminal diameter decreased in GM by 19% and in DL by 11%. Additionally, in the older age groups, GM‐40 and DL‐3, the internal elastic lamina principally was continuous, but there were also interrupted large segments of elastic lamina separated by gaps. In addition, the principal internal elastic lamina was duplicated in several places.

BACKGROUND:In cardiovascular research small pigs breeds like Göttingen ® minipigs (GM) are established animal models, but systematic data about the micromorphology of the GM vasculature at different ages are scarce. OBJECTIVE: The study was aimed at gaining knowledge about the micromorphology of the femoral artery (FA) from German Landrace pigs (DL) and GM during the period of growth over a body weight range of 10-40 kg. METHODS: FA samples from DL aged two or three months were compared to GM ones, aged 18 or 40 months using transmitted light microscopy. RESULTS: All FA samples showed typical characteristics of muscular arteries. Growth was associated with increased vessel wall thickness. In the GM this resulted in a slight decrease of the luminal diameter (LD), while in the DL pigs, an increase of the LD and smooth muscle cell content (10%) with decreased elastic fiber content (10%) has been detected. In contrast, within the 22 months lasting growth period of the GM, the tunica media content of smooth muscle cells and elastic fibers remained stable. CONCLUSIONS: FA maturation strongly depends on the pig breed and age. It can be different from what is described in humans.