C57bi 6j mice

All experimental methods have been approved by Institutional Animal Care and Use Committee of College of Charleston and conform to the Guidelines for the Use of Animals in Research of the Society of Neuroscience. Motoneuron participation in axon regeneration was studied in 63 gonadally intact male (n = 33) and female (n = 30) wild type C57BI/6J mice aged from 2–5 months old (Jackson Labs, Bar Harbor, ME). Mice were separated by sex and then randomly assigned to one of six experimental groups (see Table 1): (1) untreated without treadmill exercise, (2) untreated with treadmill exercise, (3) estradiol treatment without treadmill exercise, (4) ER antagonist treatment with treadmill exercise, (5) ER antagonist treatment without treadmill exercise, or (6) ER antagonist treatment subcutaneously administered away from transection site without treadmill exercise. An additional group of male mice were treated with systemic exogenous estradiol and ICI 182,780 at the site of nerve transection. The numbers of animals studied in each group were selected based on the results of an a priori power sample size estimate (Lenth), using data from previously published reports (English et al., 2009 (link)) and alpha= 0.05 and power = 0.8. See Figure 1 for an overview of methods.