How long does it take for the skeletal myofiber nuclei to regain a peripheral location after regeneration? More specifically, muscle appears completely regenerated after 2 weeks following cardiotoxin or crush injury, but >80% of the nuclei are in the center. How much longer does it take for the nuclei to return to the periphery of the fiber? Weeks? Months? Has anyone followed this issue carefully?
Ralston et al (2006) showed that the nuclei are preferentially localized near blood vessels (BV), particularly in slow-twitch, oxidative fibers. Lack of desmin markedly perturbs the distribution of nuclei along the fibers but does not prevent their close association with BV. Consistent with a role for desmin in the spacing of nuclei denervation affects the organization of desmin filaments as well as the distribution of nuclei. During chronic stimulation of denervated muscles, new BV form, along which muscle nuclei align themselves. They conclude that the positioning of nuclei along muscle fibers is plastic and that BV and desmin intermediate filaments each play a distinct role in the control of this positioning. J. Cell. Physiol. 209: 874–882, 2006.
It therfore not as much time that is the key factor but the physiological functioning of the surrounding tissue.
Thanks Anu. I am aware of Evelyn Ralston's work on this issue. Indeed, things like satellite cells are also 'parked' near blood vessels (and we find other interstitial progenitors near vessels as well). What I cannot find is a more descriptive work that simply follows the process and timing of nuclear repositioning from the center to the periphery. Likely things like exercise may alter the timing, but if that was tested, it would have been compared to standard (non-exercise) conditions. Hoping someone knows the 'old' literature as this may have been examined in the 60's or 70's but I cannot find it with the search terms like 'repositioning myonuclear injury, etc.'.
In 1984, Hansen-Smith showed that after 300 days, regenerated EDL from cats still have centrally located nuclei. However, more recently, Sebille showed that after 180 days in mice EDL, nuclei were back at the periphery. http://www.ncbi.nlm.nih.gov/pubmed/6465526
http://www.ncbi.nlm.nih.gov/pubmed/7659109
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