circDNMT3B alleviates retinal vascular dysfunction in a rat DM model. (a) Fluorescence signals of GFP in retinal vertical slice taken from the AAV-DJ-circDNMT3B injected diabetic rat at 3 months after injection. Nuclei were stained with DAPI. Scale bar: 20 μm. (b) Summarized data showing the changes of circDNMT3B levels, assayed by qRT-PCR, in retinas obtained from the AAV-DJ-circDNMT3B or the AAV-DJ-ciR-NC intravitreally injected normal or diabetic rats at 3 months after injection. All data are normalized to the AAV-DJ-ciR-NC injected normal retinas (control). n = 6–8, * p < 0.05, and *** p < 0.001. (c, d) Summarized data showing the changes of miR-20b-5p (c) and BAMBI (d) levels under different conditions as shown in panel b. All data are normalized to control. n = 6–8, ** p < 0.01 and *** p < 0.001. (e, f) Retinal trypsin digestion assay showing the changes in the number of retinal acellular capillaries (yellow arrows) under different conditions (e). Scale bar: 20 μm. Bar chart summarizing the average number of retinal acellular capillaries (f). n = 6–7, *** p < 0.001. (g-i) Representative ERG recordings at stimulus intensity of 0.01 cd⋅s/m2 in diabetic rats under different conditions (g). Summarized data showing the changes of a-wave (h) and b-wave (i) amplitudes. n = 6–7, * p < 0.05, ** p < 0.01, and *** p < 0.001. (j–l) Representative ERG recordings at stimulus intensity of 1 cd⋅s/m2 in diabetic rats under different conditions (j). Summarized data showing the changes of a-wave (k) and b-wave (l) amplitudes. n = 6–7, * p < 0.05, ** p < 0.01, and *** p < 0.001. Data presented as means with error bars representing standard deviation (SD). Abbreviations: AAV = adeno-associated virus, ciR = circular RNA, DAPI = 4′,6-diamidino-2-phenylindole, DM = diabetes mellitus, DNMT3B = DNA methyltransferase 3 beta, DR = diabetic retinopathy, ERG = electroretinogram, GFP = green fluorescent protein, NC = negative control, qRT-PCR = quantitative reverse-transcription polymerase chain reaction. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)