Objective To investigate the effects of advanced glycation endproducts (AGEs) on proliferation of pericytes of bovine retinal capillary vessels and expression of transforming growth factor beta;(TGF-beta;). Methods The proliferation of pericytes detected by methyl thiazolyl tetrazolium (MTT) colorimetric assay, cellular cycle of pericytes was analyzed by flow cytometry was used to analyze cell, and TGF-beta; protein expression of pericytes was observed by immunofluorescent staining. Results AGEs inhibited the proliferation of pericytes of bovine retinal capillary vessels, stopped the cellular cycle of pericytes in synthesis phase (S phase), increased the number of apoptotic cells obviously (Plt;0.01), and promoted the expression of TGF-beta; proteinof perycytes. Conclusions AGEs may promote the apoptosis of pericytes by inhibiting the proliferation of pericytes to lead the decrease of pericytes number, and may accelerate diabetic retinopathy by promoting the expression of TGF-beta; protein of pericytes. (Chin J Ocul Fundus Dis, 2006, 22: 20-23)
Objective To investigate the effect of advanced glycation end products (AGEs) on the catalase activity and the levels of malondialdehyde in cultured bovine retinal capillary pericytes (BRPs), and to investigate the relationship between oxidative stress and diabetic retinopathy. Methods Cultured BRPs were exposed to AGEs (0, 8, 32, 125, 500, 2 000 μg/ml) for four days. Activity and the levels of catalase and malondialdehyde in cultured BRPs were examined by spectrophotometry. Results AGEs decreased the catalase activity, whereas increased the levels of malondialdehyde of cultured BRPs in a dose-dependent manner (r=-0.714, r=0.748, P＜0.01).There were significant differences between BRPs cultured in 32 μg/ml AGEs and in control group (P＜0.01), while no significant differences between BRPs cultured in non-glycated bovine serum albumin and absence of bovine serum albumin were found. Conclusion Oxidative stress may be one of the reasons why the pericyte disappears in diabetic retinopathy. (Chin J Ocul Fundus Dis, 2002, 18: 143-145)
Objective To investigate the protective effect of aminoguanidine(AG),silymarin (Sil) and anisodamine (Ani) on retinal capillary pericytes cultured in glycosylation products. Methods MTT cololrimetric assay, [3H] thymidine incorporating and fluorescent indicat or fura-2 acetoxy-methyl ester (Fura-2AM) were used to study the influence of AG,Sil and Ani on the growth,DNA synthesis,and cytosolic free calcium ([Ca2 ]i)changes of pericytes cultured in the medium contained early glycation products (EGs) or advanced glycation end products (AGEs). Results Cultured in the medium contained EGs,the A value by MTT assayed and amount of [3H] thymidine incorporating in AG group and Sil group were obviously elevated than those of control group(Plt;0.01);but the [Ca2 ]iconcentration in both groups were decreased significantly comparing with control group(Plt;0.01 and 0.05).Under the condition of AEGs,only AG group was distinctly increased on the A value and amount of [3H] thymidine incorporatin g (Plt;0.01),and [Ca2 ]i concentration was markedly decreased (Plt;0.05) comparing with control group. Conclusion AG has the portective effect on pericytes against the proliferative inhibition and excessive elevation of [Ca2 ]i concentration in cytosol which are induced both by EGs or AGEs.Silymarin has the effect for those only by Egs-induced.Ani has no protective effect no pericytes nei ther cultured in medium with EGs nor with AGEs. (Chin J Ocul Fundus Dis, 2001,17:192-194)
Intravitreal injection of anti-VEGF drugs has gradually become the first-line treatment for diabetic retinopathy (DR). However, diabetic macular edema (DME) caused by DR blood-retinal barrier damage is less sensitive to anti-VEGF drugs.Therefore, it is necessary to find supplementary drugs or alternative drugs that can effectively protect the structure of the blood vessel wall. Melatonin is a hormone mainly secreted by the pineal gland, which can play a number of functions in the human body such as regulating biological rhythms, scavenging free radicals, and anti-inflammatory. In recent years, studies have shown that melatonin can improve neuronal degeneration and protect blood vessel structure through multiple mechanisms in retinopathy. In terms of its protective effect on the retinal capillary structure, melatonin can improve the damage of early DR endothelial cells and pericytes through anti-oxidative stress, anti-inflammatory, and inhibiting cell apoptosis so as to protect the integrity of the blood-retinal barrier structure. It suggests that melatonin may provide new ideas for the prevention and treatment of DR, especially with DME.