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Background The ultrastructure change and growth of corneal nerve after laser in situ keratomileusis (LASIK) are some influent factors to the stability of tear film and the sensibility of cornea.Some relevant studies are lack up to now.Objective This study is to observe the changes of ultrastructure of corneal epithelium and regeneration of corneal nerve fiber.Methods LASIK was performed on the lateral eyes of 48 New Zealand white rabbits.Rabbit eyes were excavated at instant in postoperation,one day,seven days,one,three and six months after LASIK.Change of corneal ultrastructure and corneal nerve staining were examined under the scanning electron microscope (SEM) and transmmision electron microscope (TEM) at the time points mentioned above.The numbers of microvilli of corneal epithelial cells in different postoperative time were analyzed.10% AuCl was used to evaluate the growth status of corneal nerve in different time after LASIK.Results Irregularity of microvillus of corneal epithelial cells,degrease of cell density were seen under the TEM and some cavities could been observed in the instant of postoperation.The connection abnormality of intercells,dropsy and rupture of microvillus were presented under the SEM,However,the ultrastructure of corneal epithelial cells was almost normal in 7 days after LASIK.The numbers of microvillus in corneal epithelial cells were significantly declined in the postoperative instant group compared with preoperative group (P＜0.05),but no evidently difference was found in postoperative 1 day and 7 days groups compared with preoperative group(P＞0.05).Corneal nerve staining showed that in 1 day after surgery,nerve plexus was deprivation and boundary of nerve injury was clear and nerve fibers were cut off.After one month some reborn nerve fiber grew into the cornea flap.Reborn corneal nerve fiber can be seen at center laser ablation area after six months of LASIK.Conclusion The ultrastructure change of corneal epithelial cells in the early stage after operation may be a important factor causing dry eye symptom following LASIK.The growth fashion of corneal nerve fibers is from the cutting edge to the center of corneal flap.
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Objective Choroidal neovascularization(CNV) is the main cause of blindness in over 50-years-old population. To establish an available CNV animal model is helpful for us to understand the pathogenesis and management of CNV. Purpose of present study was to observe the role of coagulation with different power of diode laser in laser-induced choroidal neovascularization model of Brown Norway (BN) rats. Methods Coagulation of 810 nm diode laser(8 - 10 spots for each eye) was performed in 36 male BN rats with the spot diameter 75 μm, shutter time 0. 1 s, power 120 mW, 140 mW and 160 mW, respectively, while 6 normal BN rats were used as contrast. CNV was evaluated by fundus examination, fundus fluorescein angiography (FFA), indocyanine green angiography(ICGA) and light microscope on day 1, 7, 14, 21, 28 and 56 after photocoagulation. Results CNV formed on the 7th day after photocoagulation in 120 mW, 140 mW and 160 mW groups and reached the peak on the 21st day according to FFA and ICGA manifestation. Incidence of CNV in 120 mW, 140 mW and 160 mW group was 51. 3%, 91. 8%, 88. 3% on FFA findings and 51.3%, 92.7%, 93.7% on ICGA findings, respectively. In 7 days after photocoagulation, inflammatory cells increased and CNV formed at the lesion. Photocoagulation plaque became thicker with pigment cells proliferating and migrating on 14 days. After that time, inflammatory cells decreased and more collagen fibers emerged. The CNV reminded till the 56th day after photocoagulation. Conclusion CNV model of BN rats can be successfully created using the different power of diode laser (from 120 through 160 mW). CNV rate under the laser coagulation with 140 mW is higher, indicating that the power of 140 mW may be a suitable parameter for diode laser-induced choroidal neovascularization model of BN rats.
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0.05). At the concentration of glutamate more than or equal to 6 mmol, the number of normal morphological cells in ISRN was significantly less than that of the control group ( P 0.05). At the concentration of glutamate more than or equal to 8 mmol, the number of normal morphological cells in RGCs layer and INL was significantly less than that of the control group ( P
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ObjectiveTo investigate the expression and distribution of epidermal growth factor (EGF), transforming growth factor-α(TGF-α), basic fibroblast growth factor (bFGF), transforming growth factor-β(TGF-β) and platelet-derived growth factor(PDGF) mRNA in the corneal epithelium and stroma of rabbit eyes, and evaluate their effects during corneal wound healing.MethodsThe expression and distribution of EGF, TGF-α, bFGF, TGF-β1 and PDGF mRNA in the corneal epithelium and stroma of rabbit eyes were detected by in situ hybridization.Results EGF,TGF-α and PDGF mRNA were only expressed in the normal corneal epithelium, but not in the corneal stroma. bFGF and TGF-β1 mRNA were expressed both in the normal corneal epithelium and stroma. ConclusionEGF, TGF-α, bFGF, TGF-β1 and PDGF can be excreted by cornea tissue,and regulate the corneal wound healing procedure.