Figure 4. Transitions of essential (e) and regulatory (r) myosin light chain (MLC) isoforms and variants thereof, in soleus and EDL muscles of the rat following a complete transversal section of the spinal cord: effect of OEG transplantation.

The proportions of e- and rMLC isoforms and of their variants, in soleus or EDL muscles were determined in Coomassie blue-stained two-dimensional (2D) electrophoretograms of whole muscle protein homogenates, as indicated in the Methods section. Different variants of the slow (s) and fast (f) rMLC (denoted 2s, 2s1 and 2s2 and 2f, 2f1 and 2f2, from less to more acidic, respectively) were identified as reported previously (Gonzalez et al. 2002). The figure reproduces representative 2D patterns together with the graphic representation of the percentage distributions of r- and eMLC isoforms (panels a and b) and rMLC variants (panels c and d) in SOL (upper panel) and EDL (bottom panel) muscles. C, sham-operated controls (n = 8); SCT, spinal cord-transected (n = 11), SCT + CT, SCT rats transplanted with OEGs (n = 9). The 2D patterns of MLCs correspond to the same muscles used as representative examples in Figs 2 and 3 (SCT + CT, 3 and 7, representing two examples of rats with good and bad functional capacity as determined by behavioural tests). 1s, 1f and 3f, fast (f) and slow (s) isoforms of essential MLCs; 2s, 2s1, 2s2 and 2f, 2f1 and 2f2, charge variants of the slow (s) and fast (f) regulatory MLC isoforms, from less to more acidic. + and − in the upper part of the 2D patterns indicate the sides of basic and acidic isoelectric points, respectively. Data are means ± s.d. of the number of animals per group indicated above, corresponding to twice the number of muscles. *P < 0.05, SCT or SCT + CT versus sham-operated controls.