MT-ND4 and Leber hereditary optic neuropathy: With the rat LHON model, Cwerman-Thibault H et al., delivered a recombinant adeno-associated viral vector containing human ND4 (rAAV2/2-ND4) in 2015 and demonstrated that human ND4 protein can be imported inside the mitochondria and did not lead to harmful effects in the rat eye.