A Comparison of Heat Shock Protein Expression in Rat Skeletal Muscle After Lengthening or Shortening Contractions

• Main Author: Holwerda, Andrew
• Other Authors: Locke, Marius
• Language: en_ca
• Published: 2013
• Subjects: Heat Shock Proteins; Muscle; Muscle Damage; Cell Stress; 0719
• Online Access: http://hdl.handle.net/1807/42865

The mechanism and subsequent patterns of Heat shock protein (Hsp) expression in skeletal muscle specific to contraction type was determined. Rat tibialis anterior (TA) muscle was forcibly lengthened (LC) or shortened (SC) in 5 sets of 20 repetitions before being removed at 2, 8, 24, 48, 72, or 168 hours and analyzed for muscle damage and Hsp25 and Hsp72 expression. Isometric peak torque was reduced to 63% and 33% (P<0.001) at 3-minutes after SC and LC, respectively. Muscle fibre damage appeared at 8h and beyond following LCs, but no damage was observed after SCs. Hsp25 content in LC muscle increased by 3.1±0.53 fold (P<0.01) at 48h and remained elevated. Hsp72 content increased by 3.8±0.66 fold at 24h and remained elevated. Neither Hsp25 nor Hsp72 content was elevated following SCs. Muscle damage associated with LCs results in a greater Hsp accumulation than SCs and 100 SCs do not result in increased Hsp content.