The Possible Protective Role of Propolis on a Model of Restraint Stress in Rat Spleen Histological & Immunohistochemical Study

Abstract

Abstract Introduction Stress is a generic term that summarizes how psychosocial and environmental factors influence physical and mental well-being. The effects of stress on the immune system are complex and depend on the nature and duration of stress. Recently, the attention of researchers has been attracted to the use of propolis in many therapeutic fields including protection of the body from the effect of stress. Aim of the Work To study the effect of immobilization stress on the structure of spleen of restrained rats and the protective role of propolis. Materials and methods Thirty-two male rats (6-8) weeks old were used in this study. The animals were randomly divided to 4 groups, as follows: Group I (Control group), Group II in which rats were treated daily with propolis (3 g/kg) by gavage for 10 days. Group III (stress group): in which rats were subjected to restraint stress test 2 h/day for 10 days. Group IV (stress group with propolis): in which rats underwent the restraint stress test as in group III and were treated daily with propolis (3 g/kg) one hour before the start of the immobilization. At the end of experiment all animals were sacrificed; spleen specimens were collected from all rats and were subjected to microscopic &immunohistochemical studies. Histomorphometry study and statistical analysis were also done. Results Compared to group I, some specimens of group III showed atrophy of spleen with significance decrease in surface area of PALS & CD3 +ve cells immune reaction. These results were accompanied by significant decrease in surface area of the follicle with apparent decrease in CD20 +ve B lymphocytes immune reactivity. Moreover, apparent increase in CD68 immune reactivity in white pulp was recorded. Other specimens revaled thickened fibrosed splenic capsule and septa, widening and congestion of splenic sinusoid and prominent hemosiderin laden macrophage. Meanwhile group IV showed general improvement in spleen architecture with daily propolis intake. Conclusion Propolis is effective as a protective measure against the effect of restrained stress on spleen in adult rats.