Microstructural changes and immunohistological analysis of pro-inflammatory cytokines in spleens of lipopolysaccharide-induced rats

Abstract

This study investigated splenic status changes in weaned Sprague-Dawley rats induced by lipopolysaccharide. There were forty 26-day-old rats selected randomly and equally divided into two groups. The treatment group received daily single doses of lipopolysaccharide, and the control group was treated with normal saline. We conducted haematoxylin-eosin staining, immunohistochemical staining and semi-quantitative optical density analysis for both groups on the 29th, 32nd, 35th and 38th days after treatment. The results indicated that splenic marginal zone in the lipopolysaccharide group was thinner or disappeared compared to that of the saline group. However, the periarterial lymphoid sheath and the diameters of splenic lymphoid follicles appeared thicker and wider than those in the saline group (P less than 0.05). The expression of interleukin-1 beta, interleukin-6 and tumour necrosis factor alpha was mainly localized within the periarterial lymphoid sheath and splenic lymphoid follicles in the lipopolysaccharide treated rats. The integrated optical density and the average optical density in the lipopolysaccharide group were greater than those in the normal saline treated group (P less than 0.05). In conclusion, splenic immune function is probably strengthened by altering microstructures and releasing pro-inflammatory cytokines following lipopolysaccharide treatment.