Morphological changes in rat liver during acute respiratory distress syndrome at different periods of experiment

Abstract

Summary. Acute respiratory distress-syndrome (ARDS) is the leading cause of death of patients with COVID-19. Liver injury is a common complication during ARDS which can occur as a result of hypoxic changes caused by respiratory disorders, systemic inflammatory response syndrome, cytokine storm and disseminated intravascular coagulation syndrome (DIC) and is a manifestation of multiple organ failure which develops with this syndrome. The aim of the study – to assess the structural changes in rat liver at different stages of the experimental ARDS. Materials and Methods. For this study 48 mature white male rats were used. ARDS was modelled through intranasal administration of lipopolysaccharide (LPS) at a dose of 5 mg/kg. Tissues were harvested after 6h, 24h, 3 days, 7 days and 14 days. Histological studies were carried out according to generally accepted methods. Results. The tissues of control group did not contain any abnormalities. 6 hours after LPS there were dilated blood-filled vessels and inflammatory cell infiltration. 24 hours after LPS the perivascular leukocyte infiltration and the portal veins dilatation remained. There were dark hepatocytes with mitotic figures. On the 3rd day there were visible signs of thrombosis in the veins and sinusoids. The liver structure was damaged. It contained dark and light hepatocyte types. There were hepatocytes with the pyknotic nuclei. On the 7th day venous thrombi began dissolving. There were many pyknotic hepatocytic nuclei visible. On the 14th day the lobular liver structure remained damaged. There were separate groups of dark and light hepatocytes visible. Hepatocytes with the pyknotic nuclei remained. There were still signs of vascular haemostasis. Conclusions. It has been established that the ARDS modelled by us causes the pathological changes of liver structural components that correspond to the liver damage during COVID-19, hypoxic liver injury and DIC caused by the clinical ARDS

Keywords

• acute respiratory distress syndrome
• liver injury
• liver failure