Nevertheless, our in vitro and in vivo observations implied that, during the pathogenesis of RP by MNU, microglial cells exhibit a prominent morphology change and Müller cells can promote activated microglia to infiltrate the ONL, which is possibly responsible for photoreceptor cell degeneration via increased secretion of CX3CL1 and upregulation of CX3CR1 expression in retinal microglial cells. This evidence concerns the gene CX3CR1 and retinitis pigmentosa 1.