Previous studies found that GAP43 expression was obviously decreased after cerebral ischemia/reperfusion insults (Zhang et al., 2019; Chen et al., 2020) and similar to these results, GAP43 level was also dramatically declined after ME in our study, whereas PNS administration enhanced axonal growth capacity by upregulating GAP43 expression with a dose-dependent trend. Here, GAP43 is linked to brain ischemia.