Extraordinarily rapid proliferation of cultured muscle satellite cells from migratory birds

Migratory birds experience bouts of muscle growth and depletion as they prepare for, and undertake prolonged flight. Our studies of migratory bird muscle physiology in vitro led to the discovery that sanderling (Calidris alba) muscle satellite cells proliferate more rapidly than other normal cell lines. Here we determined the proliferation rate of muscle satellite cells isolated from five migratory species (sanderling; ruff, Calidris pugnax; western sandpiper, Calidris mauri; yellow-rumped warbler, Setophaga coronata; Swainson’s thrush, Catharus ustulatus) from two families (shorebirds and songbirds) and with different migratory strategies. Ruff and sanderling satellite cells exhibited rapid proliferation, with population doubling times of 9.3±1.3 and 11.4±2.0 hrs whereas the remaining species’ cell doubling times were ≥24 hrs. The results indicate that the rapid proliferation of satellite cells is not associated with total migration distance but may be related to flight bout duration and interact with lifespan.

Methods
Cells were manually counted using a hemocytometer under a light microscope. 't' represents the number of hours after plating that cells were counted. 'sp' indicates the species and 'id' indicates the individual identification name for each biological replicate. 'replicate' indicates the technical replicate on each row, counts were conducted in duplicate (A and B). 'bFGF' indicates whether the basic fibroblast growth factor (bFGF) treatment was applied (Y) or not (N). 'count' indicates the total number of cell counted across 'squares_counted' number of squares on the hemocytometer. 'Dilution' indicates the dilution factor of the cell suspension added to the hemocytometer and 'volume_ml' indicates the total volume of the cell suspension.