Luminescent organic dots (O-dots) were synthesized via a one-pot, solvent-free thermolysis of citric acid in urea melt. The influence of the ratio of the precursors and the duration of the process on the properties of the O-dots was established and a mechanism of their formation was hypothesized. The multicolour luminescence tunability and toxicity of synthesized O-dots were extensively studied. The possible applications of O-dots for alive/fixed cell staining and labelling of layer-by-layer polyelectrolyte microcapsules were evaluated.

Diabetic retinopathy (DR) is a multifactorial disease characterized by reactive gliosis and disbalance of angiogenesis regulators, contributing to endothelial dysfunction and microvascular complications. This study was organized to elucidate whether poly(ADP-ribose) polymerase-1 (PARP-1) inhibition could attenuate diabetes-induced damage to macroglia and correct angiogenic disbalance in diabetic rat retina. After 8 weeks of streptozotocin (STZ)-induced diabetes, Wistar male rats were treated with PARP-1 inhibitors, nicotinamide (NAm) or 3-aminobenzamide (3-AB) (100 and 30 mg/kg/daily i.p., respectively), for 14 days. After the 10-weeks experiment period, retinas were undergone an immunohistochemical staining for glial fibrillary acidic protein (GFAP), while western blots were performed to evaluate effects of PAPR-1 inhibitors on the levels of PARP-1, poly(ADP-ribosyl)ated proteins (PARs), GFAP, and angiostatin isoforms. Diabetes induced significant up-regulation and activation of retinal PARP-1, reactive gliosis development, and GFAP overexpression compared to non-diabetic control. Moreover, extensive fragmentation of both PARP-1 and GFAP (hallmarks of apoptosis and macroglia reactivation, respectively) in diabetic retina was also observed. Levels of angiostatin isoforms were dramatically decreased in diabetic retina, sustaining aberrant pro-angiogenic condition. Both NAm and 3-AB markedly attenuated damage to macroglia, evidenced by down-regulation of PARP-1, PARs and total GFAP compared to diabetic non-treated group. PARP-1-inhibitory therapy prevented formation of PARP-1 and GFAP cleavage-derived products. In retinas of anti-PARP-treated diabetic animals, partial restoration of angiostatin's levels was shown. Therefore, PARP-1 inhibitors counteract diabetes-induced injuries and manifest retinoprotective effects, including attenuation of reactive gliosis and improvement of angiogenic status, thus, such agents could be considered as promising candidates for DR management.

No abstract

The molecular pathogenesis of diabetic encephalopathy (De), one of the serious complications of diabetes mellitus, is complex. In this study, we examined whether expression levels of SIrT1 and SIrT2 were the key for the development of brain dysfunctions and whether PARP-1 inhibitors could affect the expression of these proteins for prevention the development of De in rats with type 1 diabetes. after 10 weeks of the streptozotocin-induced diabetes mellitus (70 mg/kg), Wistar male rats were treated by i.p. injection with ParP-1 inhibitors, 1.5-isoquinolinediol (ISo) or nicotinamide (Nam) (3 or 100 mg/kg/daily i.p., respectively) for 2 weeks. The rats with blood glucose levels over 19.7 ± 2.1 mmol/l were taken into experiments. Western blots were performed to evaluate effects of PAPR-1 inhibitors on the levels of sirtuins, SIRT1 and SIRT2 expression. Diabetes induced significant reduction of SIRT1 expression and SIRT2 overexpression in brain nuclear extracts of diabetic rats compared to non-diabetic control. In brain, Nam attenuated SIrT2 overexpression in nuclear extracts of diabetic rats and slightly elevated SIRT1 expression, while ISO didn't affect expression of both sirtuins in diabetic rats. Furthermore, it was observed that in brain of diabetic rats, the ratio of free NaD/NaDh couples decreased 3.1-fold compared to non-diabetic control. The administration of ISo increased only slightly the ratio of free NaD/NaDh couples in the brain of diabetic rats while Nam increased this parameter 1.7-fold compared to diabetic rats. Therefore, we concluded that alterations in the expression of SIrT1 and SIrT2 in brain cell nuclei of diabetic rats can lead to the development of brain dysfunctions. one of the neuroprotective mechanisms of Nam action can also be realized through inhibition of SIrT2 expression in brain cell nuclei that down-regulate progression of diabetes-induced alterations and can be a therapeutic option for treatment of brain dysfunctions.