Influence of Intra-Abdominal Pressure on Morphometric Parameters of the Muscular Part of the Diaphragm in Experimental Jaundice

Laparoscopic treatment methods are widely used in surgical operations due to their minimal invasiveness and promoting rapid recovery of patients. In recent years, laparoscopic methods have made significant progress in minimally invasive hepatobiliary and pancreatic surgery. The aim of our work was to evaluate the morphometric parameters of the costal and lumbar parts of the diaphragm under the influence of pneumoperitoneum created by carbon dioxide in rats with simulated mechanical jaundice. The experimental study was performed on 60 animals, which were divided into 4 groups of 15 rats each. Group I is the control group, which simulated mechanical jaundice. The first, second and third main groups, where jaundice was simulated and pneumoperitoneum was created for 1, 2 and 3 hours, respectively. Then the diaphragm was taken and morphometric indicators were studied. When analyzing the results of morphometric measurements after 3 hours of pneumoperitoneum, the diameter of muscle fibers increased, but was 2.44 % less than the data obtained after 1 hour in the rib part and 2.17 % in the legs (p<0.01). The area of the sarcoplasm and the area of the nucleus increased in the I main group and then decreased, and at this time their parameter in the rib part was (1383.15±11.77) μm and (63.87±0.13) μm, which was 2.06 % and 2.01 % less than the indicators after 1 hour (p<0.001). In the muscle fibers of the legs, similar indicators were (1369.11±8.4) μm and (63.43±0.13) μm, i.e. decreased by 3.66 % and 2.91 % (p<0.001). The relative volume of damaged muscle fibers statistically significantly increased by 13.4 and 11.7 times, respectively, in the costal and lumbar parts relative to the control group. Pneumoperitoneum led to a wave-like increase in indicators in the main study groups, which were characterized by an increase in muscle fiber diameter, sarcoplasmic area, nuclear area, and relative volume of damaged muscle fibers compared to animals without it.