Age-related changes of rats portal vein hemodynamics and morphometry

Abstract

Introduction. Age-related changes of blood flow parameters and hepatic portal vein wall morphometry are one of the topical and insufficiently investigated issues of liver hemodynamics. The aim was to study changes of portal hemodynamics and to analyze the portal vein wall morphometry of rats at different age periods. Materials and methods. 60 mongrel rats of both sexes weighing 120–350 g were divided into three age groups. The first group included 20 rats aged 1 month, the second – 20 rats aged 6–12 months and the third – 20 rats aged more than 18–24 months. The qualitative and quantitative portal vein hemodynamics parameters were obtained by ultrasound scanners under zoletil-xylazine anesthesia. Morphometric examination of the portal vein was performed. Digital data were processed by methods of variational statistics. Results. The diameter of the portal vein in groups II and III was greater than the corresponding parameter in group I (R = – 0.40 and R = 0.64, respectively). The time-averaged average blood flow rate in the II age group increased by 9.11 % compared to the I group, decreased by 10.43 % in the III group (the differences are statistically unreliable). The volumetric blood flow rate increased moderately in age groups II and III compared to group I (by 13.07 and 11.13 %, respectively; the difference is statistically unreliable). The ratio of the volumetric blood flow rate to the weight of the animal in the II age group increased by 3.85 % compared to the I group, decreased by 11.54 % in the III group (the differences are statistically unreliable). Since the mass of animals significantly increased with age, the portal vein volumetric blood flow of old animals is likely to be decreased. Mature and old rats demonstrated significant decrease of the muscle membrane thickness, the Kernogan index and the width of the collagen layer. Conclusion. Age-related changes of rats portal hemodynamics resulted in a slight reliable increase of portal vein diameter and its cross-sectional area. Linear and volumetric parameters of blood flow were found not to have statistically reliable dependence on the age and weight of animals. Morphometric parameters of the rats portal vein wall were revealed to have pronounced changes in different age groups. The aging of the portal vein wall of elder rats consisted in a significant decrease of the muscle membrane thickness, the Kernogan index and the width of the collagen layer.