Increased neuronal activity may be sufficient to promote axon regeneration
In male thy-1-ChR2/YFP mice (optical; n = 4), cut axons were activated by blue light for 1 h before nerve repair. In control mice, nerves were cut and repaired with no treatment (untreated; n = 8), 1 h of ES (n = 5), or 2 wk of daily treadmill exercise (n = 7). Means ± SE fold changes in lengths of regenerating axons relative to untreated mice are shown. The horizontal dashed line at 1.0 reflects the amount of regeneration observed in untreated animals. Mean fold changes for all three groups shown are significantly greater than for untrained mice. Data are from Refs. 47, 62.