Changes Of Tlr4 Signaling-mediated Protein Expression With Endurance Exercise In Rats

The innate immune response is the first line of defence against infectious disease. A group of proteins that comprise Toll or Toll-like family of receptors (TLRs) has been suggested as one of the markers associated with immune and inflammatory responses. TLR4 among the TLRs produces a response by lipopolysaccharide (LPS) and controls inflammatory responses. PURPOSE: This study was performed to demonstrate the change of TLR4 signaling-mediated protein expressions in skeletal muscle during the recovery of intensive endurance exercise. METHODS: Sprague-Dawley rats (12weeks, n=35) were randomly divided into five groups(n=7 each) to time period of the exercise (pre, post 0 h, 30min, 1 h and 6 h). The rats ran on the rodent treadmill for 1 hour at the level of 75~80% VO2max (28m/min). The change of TLR4, MyD88 protein expression and NF Kappa Bp65 DNA binding activity were analyzed by western blotting in Extensor Digitorum Longus (EDL) muscle. RESULTS: TLR4 protein expression was significantly decreased by 41%(p=036) with the intensive endurance exercise, whereas MyD88 was not changed. NF Kappa B significantly increased by 51%(p=014) at 1h of recovery, but returned to the resting level 6 h post exercise. CONCLUSIONS: These results suggest an interaction between TLR4 and NF Kappa B suggesting that exercise-induced change of TLR4 expression may serve as a messenger molecules to defence inflammatory response in rat skeletal muscle.