Abstract
Microglial cell has been demonstrated to be involved in various diseases, such as Alzheimer, Parkinson diseases and multiple sclerosis. In the previous study we demonstrated that an exposure of rats to acute stress induced rapid morphological microglial activation. However, the stress-induced microglial activation was not accompanied with the induction of proinflammatory markers, IL-1β, IL-6, and iNOS. In the present study, we sought to determine the effect of adrenalectomy on the microglial activation as well as the induction of proinflammatory markers. We exposed the rats, sham-operated and adrenalectomized (ADX) rats, to restraint combined with water immersion stress for 2 hours. Immunohistochemistry with OX-42 demonstrated that morphological microglial activation is enhanced in the ADX rats as compared to that in sham-operated rats. Following the exposures to acute stress, the morphological microglial activation was intensified in the ADX-rats than sham-operated rats. Importantly, the induction of proinflammatory markers, such as IL-1β, IL-6 and iNOS, was observed only in the ADX-rats, but not in sham-operated rats, in acute stress. In addition, the morphological microglial activation as well as the production of proinflammatory cytokine markers was significantly suppressed by the treatments with glucocorticoids. Finally, double immunohistochemistry clearly demonstrated the co-localization of those inflammatory markers in the activated microglial cells. Thus, the present study suggests that glucocorticoids may have suppressive effects on the microglial activation as well as the induction of proinflammatory markers. [J Physiol Sci. 2007;57 Suppl:S117]
