RTN4 and myocardial infarction: Lactate dehydrogenase (LDH) levels in Nogo-C−/− mouse serum after MI was reserved as comparing with the increased levels in control littermates after MI (1004±76.79 in Nogo-C−/− mouse versus 1740±289.9 in control mouse after MI) (Figure 4c), indicating that knockout of Nogo-C has a protective effect on MI-induced heart injury.