NRG1 and retinitis pigmentosa: The expression of neuregulins 1 and 2, known to promote survival and neurite extension from retinal neurons during retinal development [35], and FGF2, a growth factor demonstrated to slow down photoreceptor degeneration in retinitis pigmentosa [70] and promote retinal regeneration from progenitor cells in Xenopus [71] were also increased significantly at all times post-ESMV exposure.