Histopathological Changes of Some Internal Organs of Mice Injected with Exotoxin a at Low Concentrations

Abstract

Exotoxin A is the most lethal virulence factor produced by Pseudomonas aeruginosa. It inhibits elongation factor-2 by ADP-ribosylation of EF2. This causes stop of the elongation of polypeptides. In recent study, the effect of low concentration of exotoxin A on some important internal organs of mice was studied. Four groups white mice were injected intraperitonialy with pure exotoxin A in the following manner 0.1, 0.2, 0.3, 0.4 ng\ animals.  One mouse receives normal saline inrtaperitonialy as a control. After 72 hours the mice were killed and four organs were taken, liver, spleen, lung and heart from each killed mice. Histological sections were made from each organ and stained with hematoxylin and eosin stain then examined under microscope. The resultant pathological changes were included, congestion of blood vessels, degenerative and necrotic changes, and infiltration of inflammatory cells of these organs. These pathological changes increased with increase the amount of exotoxin A injection as compared with control. No mouse was dying due to injection of exotoxin A. As a conclusion, exotoxin A at low concentrations can affect important internal organs namely, liver, spleen, lung and heart, this effect increase with increasing the concentration of exotoxin A. Lethal dose₅₀ is much higher than that of the highest concentration that causes pathological changes.

Keywords:Pseudomonas aeruginosa,Exotoxin A ,Pathological changes