Influence of acute renal failure on the mononuclear phagocytic system

Several studies show the ability of macrophages to remove particles injecte d into the bloodstream. This function seems to be increased in the presence of acute renal failure. The objective of the present study was to assess t he phagocytic function of the main organs (spleen, liver and lung) of the m ononuclear phagocytic system in renal and postrenal failures. Fifteen rats (250-350 g) were divided into three groups (N = 5): group I - control; grou p II - ligature of both ureters, and group III bilateral nephrectomy. On th e third postoperative day, all animals received an iv injection of 1 ml/kg Tc-99m sulfur colloid. Blood samples were collected for the assessment of p lasma urea, creatinine, sodium, and potassium concentrations and arterial g asometry. Samples of liver, spleen, lung and blood clots were obtained and radioactivity was measured. Samples of liver, spleen, lung and kidney were prepared for routine histopathological analysis. Plasma urea, creatinine an d potassium concentrations in groups II and III were higher than in group I (P <0.05). Plasma sodium concentrations in groups II and III were lower th an in group I (P <0.05). Compensated metabolic acidosis was observed in the presence of postrenal failure. Group II animals showed a lower level of ra dioactivity in the spleen (0.98) and lung (2.63), and a higher level in the liver (105.51) than control. Group III animals showed a lower level of rad ioactivity in the spleen (11.94) and a higher level in the liver (61.80), l ung (11.30) and blood clot (5.13) than control. In groups II and III liver steatosis and bronchopneumonia were observed. Renal and postrenal failures seem to interfere with blood clearance by the mononuclear phagocytic system .