Contrary to popular advice, applying ice after a muscle impact injury may not contribute to angiogenesis and muscle regeneration and could actually delay recovery. The results of this new research have been presented at Experimental Biology 2015.
Scientists examined two groups of rats with thigh contusions; one group received ice within five minutes of injury for 20 minutes and the other received no ice
Infiltration of inflammatory cells, vascular endothelial growth factor (VEGF) and von Willebrand factor (vWF) were lower in the group receiving ice compared to the non-icing group during the acute phase 3 days post-injury. While inflammatory cell numbers were higher during the early repair phase (7 days) for the icing group, VEGF and vWF expression remained lower.
Inflammatory cell numbers, VEGF expression, and the number of regenerating muscle fibers were all greater in the icing group vs. the non-icing group at 28 days. Muscle fiber cross-sectional area was similar between the groups at seven and 28 days post-injury.
Because inflammation can be an important component in the process of tissue regeneration, these findings suggest that ice may delay inflammation, angiogenesis, and the formation of new muscle fibers during recovery from severe muscle injury. The study authors advice clinicians to reconsider treatments such as icing and non-steroidal anti-inflammatory drugs (NSAIDs) to manage acute soft tissue injuries.
For a more complete explanation of how inflammation responds to temperature, see Ice: The Overused Modality?