Morphofunctional Parameters of the Spleen Under Immobilization Stress and the Use of Bacterial Lipopolysaccharide

The aimof this study was to determine the morphofunctional features of the spleen in rats under immobilization stress and administration of bacterial lipopolysaccharide. Material and methods.60 white Wistar rats were divided into 4 groups. The animals of the first control group were injected with saline. The rats of the second control group were injected with lipopolysaccharide. In the rats of the third group, immobilization stress was induced and the animals of this group were injectedwith saline. In rats of the fourth group, immobilization stress was also caused and lipopolysaccharide was administered in the form of the drug Pyrogenal (Medgamal, Russia) in a dose of 100  µg/kg of body weight. Fragments of the spleen were fixed in a 10% solution of neutral formalin, dehydrated in alcohols of increasing strength, and embedded in paraffin. Thin paraffin sections 4–5 µm thick were stained with hematoxylin and eosin. The area of longitudinal sections  of  the  spleen,  the  area  of  the  white  and red  pulp  were  determined planimetrically.  Using  a  screw  m icrometer eyepiece, the width of the reactive center of the lymph nodes of the white pulp, the width of the mantle and  marginal  zone  of  the  nodules,  as  well  as  the  width  of  the  periarterial  lymphoid sheath  were  measured (40–50 measurements for each animal). Results.It was found that on the 3rd day after the stress morphological signs of a sharp decrease in the activity of the white pulp were revealed. On the 8th day, pronounced recovery processes in the spleen were noted, however, complete restoration of the structure of the spleen did not occur. On the 3rd and 8th days after stress and  administration  of  lipopolysaccharide,  no  signs  of  inhibition  of  the  activity  of  the  white  and  red  pulp  were found in the spleen; morphological parameters of the spleen did not differ from the control values.