ABSTRACT
Background Treatment of corneal ulceration by transplanting drug-loaded amniotic membrane has been used widespreadly abroad,however,seldom study is found in China up to now.Objective This study was to explore the sustained release property and the efficacy of the drug-loaded amniotic membrane.Methods The bacteriostatic area of amniotic membrane fragments immersed with different concentrations (5,20,30 g/L) of levofloxacin for different time points (5,15,30,60 minutes) was evaluated by in vitro test.Bacterial corneal ulceration models were established in 20 rabbits by injected 0.7 MCF staphylococcus aureus suspension (0.1 ml) into the central corneal stroma to form the cloudy area of 4.0-6.0 mm.Then the rabbits were randomized into two groups.Regular amniotic membrane transplantation was performed laterally and 0.5％ levofloxacin drops was topically administered after operation in the amnion+levofloxacin drops group,and drug-loading amnion transplantation was used in the drug-loading amnion group.Aqueous humor of 0.1 ml was collected in 30 minutes,1 hour,2,3.5,5.5 hours after levofloxacin was administered and 1 day,3,7,10,14,21 days after operation for the detect of levofloxacin level with high-performance liquid chromatography.The corneal symptom was scored based on McNeill's criteria in 1 week,2 weeks and 4 weeks and the ulceration area was assessed under the slit lamp in the first week.The pathological examination was carried out in the fourth week after surgery.Results The mean bacteriostatic area was bigger with the increase of levofloxacin concentration,and bacteriostatic area in amnion immersed for 15 minutes was bigger than that of 5 minutes (P＜0.01).The levofloxacin concentration of aqueous humor after transplantation was decreased by extending the time,and that in 30 minutes and 5.5 hours after operation was (0.873±0.264) mg/L and (0.106±0.027) mg/L,respectively,in the amnion+levofloxacin drops group,and that in day 1,3,7 after surgery in the drug-loading amnion group was higher than at 30 minutes in the amnion+levofloxacin drops group,showing all significant differences (all P =0.00).In the first,second and fourth week after operation,the corneal symptom score was 1.7±0.6,1.3±0.5,0.2±0.4 in the drug-loading amnion group and 2.2±0.8,2.0±0.6,1.5±0.8 in the amnion+ levofloxacin drops group,with the significant differences among the different groups and time points (Fgroup =9.49,P =0.01 ;Ftime =22.96,P=0.01).The corneal ulceration area was (1.6±0.6) mm2 in the drug-loading amnion group and (3.2±0.8) mm2 in the amnion+levofloxacin drops group 1 week after operation,showing a significant difference between them (t =3.98,P =0.00).Histopathological revealed that the various layers of cornea tissue appeared irregular arrangement in the amnion + levofloxacin drops group 4 weeks after operation with 1-2 layers of new squamous epithelium.Disorder hypothallus structure,more inflammatory cells and residual vascular cavity were visible.However,new squamous epithelium of 4-5 layers was seen in the drug-loading amnion group,and inflammatory cells and residual vascular cavity were less than the amnion+levofloxacin drops group 4 weeks after operation.Conclusions Levofloxacin-loaded amniotic membrane can sustained release levofloxacin and maintain an effective drug concentration in aqueous humor,which improves the treating efficacy for staphylococcus aureus corneal ulceration.
ABSTRACT
BackgroundThe study of myopia development is always the hotspot worldwide. Recently,scientist found that some growth factor secreted by retinal nerve epithelium cells and retinal pigment epithelium(RPE)cells are associated with the development of myopia. Whenever, the absorption of RPE cells to different wave-length lights is different. ObjectiveThis study was to investigate the effects of different wave-lengths lights on the proliferation of human RPE cells, and explore the influence of different wave-lengths lights on RPE cells secreting hepatocyte growth factor(HGF) ,basic fibroblast growth factor(bFGF) and transforming growth factor-β(TGF-β).Methods The fourth to fifth passages of human embryonic RPE cells were exposed to blue light( λ =480 nm),red light( λ =775 nm) and white light. The cells of control group were harvested in normal condition. The proliferation and growth of RPE cells were assayed by MTT,and the ultrastructure of cells was examined under the transmission electron microscopy at 48 hours after light exposure of RPE cells. Enzyme linked immunosorbent assay(ELISA) was adopted to determine the concentrations of HGF,bFGF and TGF-β in the culture medium in 12,24,48,72 hours. The expression of HGF mRNA in RPE cells was detected by RT-PCR. This study was approved by Ethic committee of Fudan University. ResultsThe A490 values of the cells exposed to blue light,red light,white light and white light were 0. 0218±0. 0014 ;0. 0353±0. 0025 ;0. 0371 ±0. 0024 and 0. 0445 +0. 0046 respectively with the significant difference among 4 groups ( F =12. 579, P＜0.05 ), and A490 value in blue light group, red light group were significantly lower than that of the control group ( t =2.043 ; t =2.024, P＜0.05 ). ELISA showed that the concentrations of HGF and TGF-β in culture medium were evidently elevated as the prolongation of light exposure in various light exposure groups in 72 hours(HGF) and 48 hours(TGF-β) compared with 12 hours with a predominating rise in the control group. The statistically significant differences were found in the concentrations of HGF and TGF-β between control group and blue light group or red light group in the( all P＜0. 05 ). The bFGF level was decreased with the time increase of various light exposure with the significant differences in 72 hours compared with 12 hours( P＜0.05 ). RT-PCR revealed the considerable difference about expression of HGF mRNA in RPE cells among these four groups( P＜0. 05 ), and the lest expression in HGF mRNA was in the blue light group compared with control group( t =3. 972,P＜0.05 ). Thinning of the chromatin, decreasing of organelle and loss of cellular membrane were seen in the blue light group, but no obvious change of ultrastructure of human embryo RPE cells was found in the ret and white light groups. ConclusionsThe irradiation of different wave-length light can effect the growth and proliferation and secretion of HGF,bFGF and TGFβ in human RPE cells in vitro,implying myopia formation is associated to exposure of different wave-length light.