Histomorphometric Comparison of the Microcirculatory Bed of Rat Liver After 2 and 6 Weeks of Experimental Exposure to Cannabidiol Oil

Cannabidiol (CBD) is a well-known cannabinoid with therapeutic potential among numerous non-psychoactive compounds. CBD is characterized by a wide range of pharmacological actions on conditions such as pain, inflammation, epilepsy, anxiety, and others.The aim of the study was to investigate the histological characteristics and compare the morphometric parameters of the microcirculatory bed of rat liver after 2 and 6 weeks of experimental exposure to 10% cannabidiol oil.Materials and methods. The experiment was conducted in the conditions of the vivarium of the Danylo Halytsky Lviv National Medical University and at the Department of Pathological Anatomy and Forensic Medicine. 40 sexually mature white non-linear male rats weighing 180-230 g were used as the object of the study. Depending on the duration of CBD oil application, the animals of the experimental group were divided into 2 series of 14 individuals in each. Rats of the first series were receiving 10% CBD oil (dose 10 mg/kg/day) once a day orally dripped for 2 weeks, rats of the second series were also receiving 10% CBD oil (dose 10 mg/kg/day) once a day orally dripped for 6 weeks. The control group included 12 sexually mature white male rats, 6 individuals in each series of the experimental study. All experiments, as well as housing, care, feeding, marking and euthanasia were carried out in compliance with the requirements of the European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes (Strasbourg, 1986), Council of Europe Directive 2010/63/EU, Law of Ukraine No. 3447-IV “On the Protection of Animals from Cruelty to Animals”. Histological and morphometric studies of the vessels of the liver microcirculatory bed of two series and the control group were performed using statistical methods. The reliability criteria of Pearson (χ2), Mann-Whitney (U), Wilcoxon T-test, McNemar p (McN) were used. The difference was considered statistically significant at a minimum significance level of p<0.05.Results. Based on the morphological study of the vessels of the liver microcirculatory bed under the experimental influence of CBD for 2 and 6 weeks, it was found that the histological structure of the vascular compartment did not change. Comparative morphometric analysis of the vessels of the liver microcirculatory bed indicates the absence of a significant difference in the average external diameters of the interlobular artery after 6 weeks of CBD exposure with the control group (p>0.05). No significant difference in the average diameters of the sublobular and collecting veins after CBD exposure for 2 and 6 weeks (p>0.05), as well as hemodynamic disorders, which is important for the liver blood outflow system. Similarly, no significant difference in the average diameter of the portal vein with the control group in the two terms of the experiment was found (p>0.05), and no hemodynamic changes were recorded. It was found that minor hyperemia was diagnosed in single central veins after both 2 and 6 weeks of experimental exposure to CBD, but the relative values did not significantly differ from the control group in both series of the experiment (p>0.05).Conclusions. Comparative morphometric analysis of the vessels of the liver microcirculatory bed at the end of 2 and 6 weeks of the experiment indicates the safety of using 10% CBD oil (dose 10 mg/kg/day).