STRUCTURAL CHANGES IN THE WALL OF THE ABDOMINAL AORTA IN MODELINGOF LONG-TERM CANNABINOID RECEPTORS CB1 BLOCKADE IN LABORATORY ANIMALS
The purpose of the work is to detect the effect of long-term cannabinoid receptors CB1 blockade on the abdominal aorta wall structure in experimental rats. Materials and methods. The study was performed on two groups of 100-day-old male Wistar rats. The first group was made up of intact animals. The second group consisted of animals that were administrated with rimonabant hydrochloride solution (10 mg/kg-1 of body weight) per os with drinking water per day. The experiment duration was 10 days, and then the abdominal aorta of each animal was isolated for the histological measurements. Computer morphometry, the study of the subendothelial layer thickness with the internal elastic lamina and media, the ratio of the lumen diameter to the vessel wall were conducted in the abdominal aorta wall structure assessment. Results. It has been established that long-term cannabinoid CB1 receptors blockade in 100-day-old male Wistar rats resulted in morphological changes in all layers of the abdominal aorta wall that manifested in alterations of endothelial cells structure and their desquamation in the intima. The inner elastic lamina became thin and discontinuous. The thickness of the media was not uniform and there was a decrease in the number of elastic laminae as well as an increase in the number of chaotically oriented smooth muscle cells. Changes in adventitia manifested in swelling and loosely packed fibers with their increased dispersion. The number of collapsed vasa vasorum was decreased to single and hypertrophy of the nerve ganglia was observed. There was a thinning of the internal lamina and a decreased percentage of the lumen and vessel components of the wall at the expense of other tissues. Conclusions. The study results indicate that the long-term cannabinoid CB1 receptors blockade is a factor that damages endothelium of the abdominal aorta and leads to a decrease in elastin and proliferation of smooth muscle cells in the media, as well as a decrease in the percentage of the lumen and wall of the abdominal aorta at the expense of other tissues.