gms | German Medical Science

Purpose: To induce unilateral photoreceptor degeneration by intravitreal injections of iodoacetic acid (IAA) and N-methyl-N-nitrosourea (NMU) in comparison to their systemic application and the genetic rd10 mouse model.

Methods: C57BL/6J wild type mice were treated with intraperitoneal (MNU), intravenous (IAA), and intravitreal injections (IAA and MNU) at different concentrations. Mice were observed with ERG and OCT in a two week follow-up and finally analyzed by immunohistochemistry.

Results: Systemic injections of both IAA and MNU induced high systemic toxic effects and weight loss, an extinction of the ERG, and a thinning of the retina as observed by OCT and immunohistochemistry. Animals systemically treated with MNU, showed a selective outer retinal degeneration comparable to that observed in rd10 mice as verified by immunohistochemistry. Mice receiving intravitreal injections nearly exhibited no reduction of welfare. After intravitreal injection of IAA, cataractous changes and inflammatory reactions as well as a thinning of the entire retina was observed, mostly prominent in the inner part of the retina. Intravitreal application of MNU displayed photoreceptor degeneration comparable to that found after systemic application or in the rd10 model; immunohistochemistry revealed selective photoreceptor degeneration of variable degree.

Conclusion: Intravitreal injection of MNU led to comparable retinal changes as observed after intraperitoneal application or in the genetic rd10 mouse model and is useful to induce photoreceptor degeneration without systemic side effects, while maintaining a healthy intraindividual control eye.