Lens Injury Has a Protective Effect on Photoreceptors in the RCS Rat

Lens injury induced activation of retinal glia, and subsequent release of ciliary neurotrophic factor (CNTF) and leukaemia inhibitory factor (LIF) potently protect axotomised retinal ganglion cells from apoptosis and promotes axon regeneration in the injured optic nerve. The goal of the current study was to investigate if similar effects may also be applicable to rescue photoreceptors from degeneration in a model of retinitis pigmentosa. Lens injury was performed in the Royal College of Surgeons (RCS) rats at the age of one month. The survival of photoreceptors was evaluated histologically, and retinal function was analysed by electroretinography (ERG). Expression of CNTF was also analysed. Lens injury significantly enhanced the survival of photoreceptors 1 month after surgery compared to untreated controls, which was associated with an enhanced ERG response. In addition, lens injury significantly protected photoreceptors from degeneration in the contralateral eye, although to a much lesser extent. We could show that lens injury is sufficient to transiently delay the degeneration of photoreceptors in the RCS rat. The observed neuroprotective effects may be at least partially mediated by an upregulation of CNTF expression seen after lens injury.