AJP - Cell Physiology, Vol 237, Issue 3 166-C176, Copyright © 1979 by American Physiological Society
Reversible suppression of skeletal myotube formation in vitro obtained by varying [CO2]
R. J. Przybylski, J. C. Bullaro and R. MacBride
In primary cultures of chicken skeletal muscle, decreasing the [CO2] of the
gaseous phase below 10(-3)% resulted in inhibition of cell proliferation
and cytolysis. With 10(-3)% CO2-air, cell proliferation was slightly
retarded and myotube formation was inhibited approximately 90% compared to
cultures receiving 5% CO2-air. Changes in pH were not effective. Culture in
low [CO2] resulted in the accumulation of lipoidal inclusions and unique
cytoplasmic structures. Increasing time in culture with low [CO2] resulted
in an increase in the length of G1 of the cell cycle. The inhibition was
reversed by the addition of 5% CO2-air at any time in culture up to 2 wk
with a minimum time of 3--6 h required. Lipoidal inclusions decreased in
number and the unique cytoplasmic structures were absent. During the first
3 days in culture, myoblasts showing dependence on [CO2] for myotube
formation increased in number, and the effect of elevated [CO2] on these
cells was long lasting. The data suggest that some aspect of myoblast
differentiation relating to cell recognition and fusion is affected by
decreased [CO2].
