Experimental effect of retinoic acids on apoptosis during the development of diabetic retinopathy

Abstract

Nami Nishikiori1,2, Makoto Osanai2, Hideki Chiba2, Takashi Kojima2, Shuichiro Inatomi1,2, Hiroshi Ohguro1, Norimasa Sawada2Departments of 1Ophthalmology and 2Pathology, Sapporo Medical University School of MedicinePurpose: This study was conducted to investigate whether retinoic acids (RAs) had any effect on apoptosis during the development of diabetic retinopathy.Methods: To investigate whether RAs had any effect on apoptosis during the development of diabetic retinopathy, we housed 32 C57BL/6 male mice and induced diabetes in 24 by intra peritoneal injections of streptozotocin (STZ; Sigma, St Louis, MO) and treated 16 of the diabetic mice with the RAs, all-trans-retinoic acid (ATRA) (seven mice) and 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)carboxamido] benzoic acid (Am580) (nine mice). The other eight mice were used as diabetic controls. We then measured apoptosis in the retina by TdT-dUTP terminal nick-end labeling assay.Results: RAs inhibited the apoptosis of retinal cells in diabetic retinopathy. Many apoptotic cells were observed in retinas of the eight diabetic control mice (mean value and SD: 37.8 ± 6.9), whereas when diabetic mice were treated with RAs, the number of apoptotic cells significantly decreased (mean value and SD: 9.9 ± 6.4 for the seven ATRA-treated diabetic mice and 9.8 ± 5.9 for the nine Am580-treated diabetic mice) (p < 0.05).Conclusion: Treatment with RAs decreases apoptosis during the development of diabetic retinopathy.Keywords: retinoic acids, apoptosis, diabetic retinopathy, glial cell line-derived neurotrophic factor