2P291 Effects of social stress exposure on lipopolysaccharide-induced responses in C57BL/6J mice

• Published in: Journal of Pharmacological Sciences 2003, Vol.91 (suppl.1), p.196-196
• Main Authors: Takashi Tsuboi, Yuji Ikegaya, Maki K. Yamada, Norio Matsuki, Nobuyoshi Nishiyama
• Format: Article
• Language: Japanese
• ISSN: 1347-8613

Social stress leads to multiple discriminative changes, and the immune system is not the exception. Indeed, proinflammatory cytokines are increased under the anxious conditions. Since these cytokines are members of the natural immunity, the infection or endotoxin exposure may produce various responses depending on the status of subject. Although it is known that social stress exposure affects some of the proinflammatory cytokines in rodents, the response of IL-12 still remains unknown, which works especially in the early stage of the natural immunity and plays an important role in bridging to the adaptive immunity. In the present study, we investigated the effects of bacterial endotoxin lipopolysaccharide (LPS) injection after repetitive exposure to social disruption (SDR). In the SDR procedure, an aggressive mouse was placed into the colony, and the resident mice were attacked for 2 hours in the evening for six days. When LPS (50μg/kg, i. p. ) was administered on the next day after the last SDR, the stressed animals showed a more severe loss in body weight than control mice in the following 24 hours. While plasma concentration of IL-12 p40 subunit was robustly increased in both stressed and control mice, there were no differences between the two groups. These results indicate that circulative p40 IL-12 following LPS exposure may not be a causative factor for enhanced body weight reduction in stressed mice.