ABSTRACT
Background Light stimulation at different wavelength influences the development of eyes.It has been showed that blue light can inhibit the growth of eyeball.To study whether blue light exposure can delay the extension of myopia is an interested research project.Objective This study was to investigate the effect of blue light with short wavelength on ocular growth in form deprived myopia (FDM) in guinea pigs and provide a new option for the prevention and treatment of myopia.Methods Thirty-six 2-week-old guinea pigs were reared in the environment of white light.The right eyes of the animals were occluded to establish the FDM models.The models were randomized into the deocclusion + blue light exposure group,simple deocclusion group and continuous occlusion group according to the random number table.The right eyes of the models were deoccluded for 1 hour per day to give the blue light (430 nm) irradiation in the deocclusion + blue light exposure group,and the right eyes were deoccluded for 1 hour per day only in the simple deocclusion group.In the continuous occlusion group,the right eyes of the models were occluded until the end of this experiment.Anterior chamber depth (ACD),lens thickness (LT) and vitreous cavity depth (VCD) were measured by A-type sonography.The binocular diopter of the guinea pigs was detected using retinoscopy in the mydriatic condition.In the fourth week after experiment,the retinal sections were prepared for the regular histopathological examination,and the scleral tissues next to 1 mm from optical nerve were exacted to obtain the dry weight of scleral tissues.Results In the right eyes of the animals,no significant differences were found in the diopter,ACD,LT and VCD before experiment among the 3 groups (all at P＞0.05).At the end of experiment,the refraction of right eye in the deocclusion + blue light exposure group,simple deocclusion group and continuous occlusion group was (+1.11±0.17)D,(+0.90±0.15)D and (-2.73±0.19)D respectively,with a significant difference among them (F=1 445.470,P=0.000).The VCD in the three groups was (3.70±0.09) mm,(3.78±0.11) mm and (3.91 ± 0.08) mm,respectively,showing a significant difference (F =13.243,P＜0.01).In addition,the dry weight of sclera tissues was (0.61 ±0.09)mg in the deocclusion + blue light exposure group,(0.54± 0.08)mg in the simple deocclusion group and (0.43 ± 0.07)mg in the continuous occlusion group,with a significant difference among the 3 groups (F=10.458,P＜0.01).However,there were no significant differences in the ACD and LT among the 3 groups (F=0.203,0.084,both at P＞0.05).Moreover,in the left eyes,no significant differences were found in the diopter,ACD,LT and VCD before experiment among the 3 groups (all at P＞0.05);while at the end of the experiment,the diopter of the continuous occlusion group was significantly lower than that of the deocclusion + blue light exposure group and simple deocclusion group (all at P＜0.05).No significant differences were seen in the ACD,LT,VCD and dry weight of sclera among the 3 groups (all at P＞0.05).Retinal structure was normal in the left eyes of various groups.However,the retinas were thinner in the right eyes of the deocclusion + blue light exposure group with clear layers; while atrophy of the outer segment of photoreceptor and disorder of cell arrangement were seen in the right eyes of the continuous occlusion group.Conclusions During sensitive period of visual development,blue light stimulation can arrest the extension of posterior sclera and elongation of vitreous cavity,which restrains development of myopia.This blue light at the wavelength of 430 nm is safe to retina.
ABSTRACT
Background Oxidative stress-induced apoptosis of human lens epithelial cells (LECs) is associated with c-Jun N terminal kinase (JNK) pathway.Quercetin possesses the antioxidation by inhibiting the JNK pathway.However,whether quercetin can protect LECs from the oxygen-induced damage is still not proved.Objective This study attempted to invatigate the effects and its mechanism of quercetin against hyperbaric oxygeninduced LECs apoptosis. Methods Human LECs line SRA01/04 was cultivated and passaged in MEM medium containing 10％ fetal bovine serum and 0.5％ non-essential amino acids for 2 hours,with or without 20 μmol/LSP600125 or 1 μmol/L quercetin prior to exposure to hyperbaric oxygen.Each exposure session remained 6 hours in 99％ O2 and 1％CO2 with a pressure chamber at 588 kPa.The viability of human LECs was detected by MTT.Cell apoptosis was assessed by flow cytometer using Annexin V-FITC apoptosis detection.The expression of JNK/p-JNK,c-Jun/p-c-Jun,caspase 3 and caspase 9 were detected by Western blot. Results LECs viability (A570 ) was 0.835 ±0.082,0.450±0.083,0.654±0.079,0.649±0.090 respectively in the blank control group,hyperbaric oxygen exposed group,hyperbaric oxygen+SP600125 group and hyperbaric oxygen+quercetin group.The A570 in the hyperbaric oxygen exposed group was significantly lower than the blank control group ( P =0.000),but those in hyperbaric oxygen + SP600125 group and hyperbaric oxygen+quercetin group were significantly higher than the hyperbaric oxygen exposed group ( P =0.003,0.002 ).The numbers of apoptosis cells were 3.17 ±0.74,19.77 ± 1.44,8.45 ±0.93,7.79 ±0.78 respectively in the blank control group,hyperbaric oxygen exposed group,hyperbaric oxygen+SP600125 group and hyperbaric oxygen+quercetin group.Apoptotic LECs were significantly increased in the hyperbaric oxygen exposed group compared with the blank control group ( P=0.000),but those in the hyperbaric oxygen+SP600125 group and hyperbaric oxygen+quercetin group were significantly reduced in comparison with hyperbaric oxygen exposed group (both P=0.000).In additional,expressions of p-JNK,p-c-Jun,caspase 3 and caspase 9 proteins in the cells were elevated in the hyperbaric oxygen exposed group compared with the blank control group (all P =0.000 ),however,those in the hyperbaric oxygen + SP600125 group and hyperbaric oxygen + quercetin group were declined when compared with the hyperbaric oxygen exposed group( all P＜0.05 ). Conclusions JNK pathway is involved in the apoptotic procedure of human LECs induced by oxygen stress.SP600125 and certain concentration of quercetin can interdict the JNK signal pathway and endogenous apoptosis of LECs and further alleviate hyperbaric oxygen-induced damage of LECs.
ABSTRACT
BackgroundMonocyte chemotactic protein-1 (MCP-1)plays an important role in the tumor,inflammation,diabetic retinopathy and other neovascular disease,but the expression and the role of MCP-1 in the oxygen induced retinopathy(OIR) model have rarely been reported. Objective This study was to investigate the expression of MCP-1 in the retina development of newborn mouse and in mouse models with OIR.Methods C57BL/6J newborn mice were divided into two groups and 60 mice in each group.Mice in OIR group were exposed to 75％ oxygen for 5 days and then to room air.All mice in normal control group exposed to room air only.Ten mice in each group were randomly chosen and sacrificed at postnatal 5,7,12,14,17,21 days.The expression of MCP-1 in mouse retina was detected with the method of immunohistoehemistry and reverse transcription polymerase chain reaction(RT-PCR).Results MCP-1 positive cells were seen in normal mouse retina.Up-regulation of MCP-1 positive cells was detected both in 12 days in normal control group and in 14 days in OIR group.MCP-1 mRNA was detected in mouse retina at 5 days,and a transient up-regulation of MCP-1 mRNA was observed in 12 days in normal control group.MCP-1 mRNA in OIR group significantly increased in 14 days in comparison with the normal control group( P =0.028,P =0.001 ). Conclusions Expression of MCP-1 is detectable in whole retinal development procession of mice.A transient up-regulation of MCP-1 expression is detected in the critical period of retinal vascular development in mice models with OIR,which is closely related to the retinal vascular development and progression of retinal new vessels.