INDICES OF THE CAPILLARY DIAMETER IN NORMAL RETINA AT DIFFERENT TERMS OF EXPERIMENTAL OPIOID INFLUENCE AND IN THE SUBCHRONIC AND CHRONIC PERIODS OF THEIR CORRECTION
Authors: Paltov Ye.V. 
Published: April 2024

In Ukraine, according to the latest biobehavioral research, the estimated number of people who inject drugs was 317000 people (on the controlled territory of Ukraine), of which 200661 people (63.3% of the total number) use only opioids, 38674 people use stimulants (12.2% of the total number), 77665 people practiced mixed use of narcotic substances (24.5%). Increasingly, doctors of various specialties face the problem of treating various nosologies in people with opioid addiction. It dramatically complicates the process of correcting the main pathology due to the consequences arising from the chronic use of opioid drugs. One of these factors is the long-term use of opioid analgesics for therapeutic purposes, as well as the use of opioid drugs without medical indications by people belonging to the category of drug addicts. At present, the issue of structural reorganization in the layers of the retina and links of its hemomicrocirculatory bed during long-term use of opioid drugs and the possibility of correcting the resulting changes in the subchronic and chronic periods of experimental opioid exposure remains unclear. That is why we decided to supplement, expand and deepen information about these processes by conducting our own research in this direction.The purpose of the study is to find out the dynamics of changes in the diameter of the capillary link of the hemomicrocirculatory bed of the retina at different times of experimental opioid exposure and to establish the possibility of correcting these changes in the subchronic and chronic periods. Material and methods. The research material was sexually mature, outbred, white male rats, in number 125 animals weighing 160-270 g, aged 4.5-7.5 months. The initial dose of nalbuphine during the first 2 weeks was 0.212 mg/kg, the next 2 weeks (III-IV weeks) – 0.225 mg/kg, the next (V-VI weeks) – 0.252 mg/kg, the next (VII-VIII weeks ) – 0.260 mg/kg, the next (IX – X weeks) – 0.283 mg/kg, the next (XI – XII weeks) – 0.3 mg/kg, and during (XIII – XIV weeks) – 0.45 mg/ kg Correction was carried out in the early and late periods of opioid exposure, where the dose of pentoxifylline was 2.857 mg/kg. The morphometric study of the diameter of retinal capillaries in normal conditions at different times of experimental opioid exposure and during correction was performed using histological preparations according to generally accepted methods.Research results. With the help of our statistical analysis of the capillary component of the retina, we established the diameter parameters of the retinal capillaries, which were 5.9 [5.6; 6.1] μm., which made it possible to assess the degree of vascularization of the retina in the norm. When corrected at the subchronic period, we found that there was no significant difference between the average values of capillary diameters (p>0.05) between the control group and the 14th subgroup (2 weeks of nalbuphine administration with withdrawal followed by 4 weeks of pentoxifylline administration). There was a significant increase in mean capillary diameter when comparing subgroup 10 (2 weeks of nalbuphine followed by 4 weeks withdrawal) (p<0.05) with subgroup 12 (2 weeks of nalbuphine followed by 4 weeks of pentoxifylline) (p<0.05). 0.001), compared to the data of the control group. Capillary diameters in subgroup 10 (2 weeks of nalbuphine administration followed by 4 weeks withdrawal) were increased by 18.7% (p>0.05), compared to subgroup 5 (6 weeks of nalbuphine administration). The situation was significantly unfavorable in comparison with the previous results in subgroup 12 (2 weeks of nalbuphine administration with the addition of 4 weeks of pentoxifylline) - by 32%, compared to the diameters of capillaries in subgroup 14 (2 weeks of nalbuphine administration with withdrawal and followed by 4 weeks of pentoxifylline administration). When corrected for the chronic period, we found that, compared to the control group, capillary diameters increased the least in the 15 subgroup of 10 weeks (6 weeks of administration of nalbuphine with withdrawal and followed by 4 weeks of administration of pentoxifylline) (by 35%). Capillary diameters were significantly larger in the 11-week 10-week subgroup (6 weeks of nalbuphine followed by 4-week withdrawal) (by 49%), while in the group with ten weeks of experimental opioid exposure (by 57%). The most unfavorable situation was in the 13th subgroup of 10 weeks (6 weeks of administration of nalbuphine with the addition of pentoxifylline for 4 weeks) (by 63%).Conclusion. As a result of our research, we can conclude that in the subchronic and chronic periods of correction of opioid exposure, the situation was most unfavorable in the subgroups where correction was carried out with simultaneous administration of nalbuphine and pentoxifylline. From the above, it is possible to draw a clear conclusion that in no case can these drugs be combined during the medical correction of pathomorphological changes in the retina and links of its hemomicrocirculatory bed in experimental opioid retinopathy.