Table II.

Percentage of different MHC-typed fibers in EDL and soleus muscles from wild-type and ACTC^Co/KO mice

Age	Muscle	MHC fiber type	Wild type	ACTCCo/KO	P-value
mo			%	%
4.5	EDL	MHCIIB	67.04 ± 2.74	61.12 ± 2.97	0.124
4.5	EDL	MHCIIX	31.06 ± 2.44	40.38 ± 2.44	0.014a
4.5	EDL	MHCIIA	17.51 ± 1.05	19.64 ± 1.59	0.091
10	EDL	MHCIIB	71.10 ± 4.07	74.85 ± 2.54	0.257
10	EDL	MHCIIX	25.12 ± 2.40	35.08 ± 3.45	0.038a
10	EDL	MHCIIA	20.32 ± 4.73	13.85 ± 1.80	0.537
4.5	soleus	MHCI	46.24 ± 1.21	63.54 ± 3.44	0.0002b
4.5	soleus	MHCIIA	52.91 ± 1.62	40.04 ± 3.37	0.0021c
10	soleus	MHCI	47.03 ± 2.98	74.97 ± 3.15	0.0095c
10	soleus	MHCIIA	49.70 ± 3.20	22.75 ± 2.75	0.0043c

Muscles were collected from 4.5 (n = 8 or 9)- and 10-mo-old (n = 5) wild-type and ACTC^Co/KO mice and stained with anti-MHCI, anti-MHCIIA, anti-MHCIIB, and anti-MHCIIX antibodies. Because of the presence of hybrid fibers expressing more than one MHC type (not depicted), the total percentage of myofibers in the EDL muscles of both types of mice is >100%.

^aP < 0.05.

^bP < 0.001.

^cP < 0.01.