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The Response Of Voluntary Physical Activity Via TLR3 And TLR7/8 In Mice: 537May 27 9:30 AM - 9:45 AM

Yano, Hiromi; Matsumoto, Takashi; Yoshida, Chie; Uchida, Masataka; Tanaka, Yohei; Kawanishi, Noriaki; Shiva, Daisuke; Woods, Jeffrey A. FACSM

Medicine & Science in Sports & Exercise: May 2009 - Volume 41 - Issue 5 - p 5
doi: 10.1249/01.mss.0000353272.71443.84
A-15 Free Communication/Slide - Immunology: MAY 27, 2009 9:30 AM - 11:00 AM ROOM: 4C4

1Kawasaki University of Medical Welfare, Kurashiki, Japan. 2Oita University, Oita, Japan. 3Okayama University Graduate School, Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan. 4Waseda University, Tokorozawa, Japan.5University of Illinois at Urbana-Champaign, Urbana, IL.


(No relationships reported)

It is well known that infection decreases physical activity performance in humans and animals, but the mechanisms is unknown. Many researches have used lipopolysaccharide (LPS) as a model of bacterial infection to induce sickness behavior. However, how voluntary physical activity is regulated during viral infection is not known. The pathogen-associated molecular patterns (PAMPs) are recognized by the family of toll-like receptor (TLRs) on host mammalian cells which signal host cells to induce a response. Among synthetic double-stranded (ds) RNAs, polyriboinosinic: polyribocytidylic acid (poly I:C) activates immune function via TLR3. Additionally, among synthetic single-stranded (ss) RNAs, R848 activates it via TLR7/8.

PURPOSE: To determine whether dsRNA and ssRNA are responsible for reduced spontaneous physical activity, we measured poly I:C- and R848-induced changes in voluntary wheel-running activity in mice.

METHODS: In this experiment, the C3H/HeN mice were injected with poly I:C and R848 (0, 1, and 5 mg/kg, i.v., respectively) and then the wheel-running activity of mice were measured for 24 hours.

RESULTS: In these experiments, poly I:C and R848 treatments significantly increased plasma IFN-b and IFN-a. Low and high dose of poly I:C treatments significantly reduced wheel-running activity (37% and 70% compared with pre-injection, respectively). Additionally, R848 treatments also dose-dependently reduced wheel-running activity (33% and 67% compared with pre-injection, respectively).

CONCLUSION: Our results suggest that the transient reduction in physical activity after dsRNA and ssRNA injection is induced dose dependently. In conclusion, ligation of TLR3 and TLR7/8 reduce running wheel activity. Future investigations need to determine which protein products are responsible for this reduction.

© 2009 American College of Sports Medicine