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Objective:To compare the preservation effect of DX preservation solution and glycerin preservation solution on the corneal stromal lens.Methods:Sixty intact corneal stromal lens samples were collected during femtosecond small incision lenticule extraction (SMILE) from 60 myopic eyes of 30 subjects at Qingdao Eye Hospital of Shandong First Medical University from February 2019 to May 2019.The samples were randomized into DX preserved 1-day group, DX preserved 1-week group, glycerin preserved 1-day group, glycerin preserved 1-week group and glycerin preserved 2-week group according to the different preservation methods, with 10 samples in each group.No intervention was done in the samples of the normal control group.Trypan blue staining was used to count the number of dead cells in the corneal stromal lens.The morphological structure of the corneal stromal lens was examined with an optical microscope, and its ultrastructure was observed under the transmission electron microscope.This study adhered to the Declaration of Helsinki.Written informed consent was obtained from each patient prior to any medical intervention.The study protocol was approved by an Ethics Committee of Qingdao Eye Hospital of Shandong First Medical University (No.2019-30).Results:The number of dead cells was (53.1±14.2), (50.8±9.8), (70.4±13.6) and (172.8±31.7) and (182.8±14.2) cells/field in the DX preserved 1-day group, DX preserved 1-week group, glycerin preserved 1-day group, glycerin preserved 1-week group and glycerin preserved 2-week group, respectively, showing a significant difference among the five groups ( F=16.37, P<0.05). There was no significant difference between the DX preserved 1-day group and 1-week group ( P>0.05). The number of dead cells was significantly less in the glycerin preserved 1-day group than that of the glycerin preserved 1-week group and glycerin preserved 2-week group, and the number of dead cells was significantly increased in the glycerin preserved 1-week group compared with the DX preserved 1-week group (all at P<0.05). The arrangement of collagen fibers of the corneal stromal lens was regular and the cells were intact in the normal control group, DX preserved 1-day group and DX preserved 1-week group.The tissue edema, bare cell nuclei and loose collagen fibers were found in the samples in the glycerin preserved 1-day group.The corneal stromal lens was compact and the collagen fibers were dense and the nuclei were intact in the DX preserved 1-day group and DX preserved 1-week group.The distribution of the cells was sparse and the cell structure was abnormal under the transmission electron microscope in various glycerin preserved groups. Conclusions:The structure of corneal stromal lens can be well preserved for one week by DX storage solution.The preservation effect of DX solution is better for fresh human corneal stromal lens than glycerin solution.
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@#AIM: To study the biocompatibility of double-layer corneal stromal lens attactched by fibrin sealant(FS)<i>in vivo</i>, and to explore the feasibility of using this material for corneal transplantation.<p>METHODS: Fifteen healthy and clean New Zealand white rabbits were selected for a self-control study. The right eye of the rabbit was used as the experimental eye and the left eye was used as the control eye. The experimental eyes used FS adhesived double-layer corneal stromal lens as the material for lamellar keratoplasty, and the control eyes did not undergo manual intervention. At 7,14, and 28d after surgery, a hand-held slit lamp was used to observe the cornea of the rabbits and then score the biocompatibility. The corneas of both eyes were taken for histopathological examination by HE staining to observe the corneal recovery at the same time.<p>RESULTS: Slit lamp observation results showed that by 28d after the operation, the corneal epithelium of the experimental eyes grew well, the degree of corneal transparency was basically restored, the degree of edema was reduced, the growth of neovascularization to the corneal edge was not aggravated, and no rejection reaction such as epithelial and endothelial rejection lines were seen; The control eyes had clear corneas and smooth corneal epithelium. The results of biocompatibility score showed that the degree of corneal implant edema gradually decreased, the transparency gradually recovered, the rejection reaction was less, and the biocompatibility of corneal implants was better in the experimental eyes after corneal transplantation. There were no differences in the degree of corneal transparency, edema and neovascularization growth between the experimental and control eyes at 28d after surgery(<i>P</i>>0.01). The results of histopathological examination showed that by 28d after corneal transplantation, there were 4-5 layers of corneal epithelial cells covering the surface of the implant in the experimental eyes, the corneal collagen was neatly and regularly arranged, no obvious inflammatory cell infiltration was seen in the implant, the boundary between the two lenses disappeared, the interlayer FS was completely absorbed by the organism, the implant was fused with the implant bed, and no obvious demarcation was seen.<p>CONCLUSION:Using FS pasted double-layer corneal stroma lens as a graft for lamellar keratoplasty has better recovery, less rejection and better biocompatibility, and can be used for lamellar keratoplasty.
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@#AIM: To investigate the feasibility of constructing corneal stromal scaffolds and the optimal preservation conditions of corneal stromal lenses obtained from the small incision lenticule extraction(Smile)surgery.<p>METHODS: Constructing a bilayer lens by adhering together two corneal stromal lenses with human fibrin sealant(FS). Human corneal fibroblasts were isolated and cultured from Smile derived corneal stromal lenses <i>in vitro</i>, and the toxicity of FS on human corneal fibroblasts was detected by MTT method. The bilayer lenses were then placed in anhydrous glycerin, sodium hyaluronate eye drops, a simulated wet room environment and fetal bovine serum groups respectively, and stored at 4℃ for 14d. The transparency, hardness and stability of the scaffolds were then compared. Afterwards, the bilayer lens scaffolds were stored in anhydrous glycerin at room temperature, 4℃ and -20℃. After 14d of preservation, the diverse effects of temperature on the transparency and hardness of the scaffolds were compared.<p>RESULTS: MTT results showed that the cells of the experimental group and the control group had similar proliferation trend within 0-72h. The cytotoxicity rating of the experimental group was 0 at 36-48h and 1 at 24h and 60-72h. The relative survival rate of the cells within 0-72h was over 90%. FS-bonded bilayer lens scaffold had a smooth surface, close bonding, good transparency and suitable hardness. After 14d of storage at 4℃, none of the nine bilayer lens scaffolds in the anhydrous glycerol group showed signs of cracking cracking after rehydration, and their transparency was good. In the sodium hyaluronate group, three of the nine scaffolds cracked and the remaining six were still intact. In the simulated wet room environment group, none of the 9 scaffolds cracked, but there were different degrees of shrinkage, their surface was rough and transparency was lower. In the fetal bovine serum group, all the 9 stents were cracked, and the single corneal stromal lens was soft and edema was serious. Out of the 15 bilayer lens scaffolds preserved in anhydrous glycerol at room temperature, 2 remained colourless and transparent, 5 slightly yellowed but still remained transparent, 8 yellowed substantially with a significant reduction in transparency. Out of the 15 bilayer lens scaffolds preserved in anhydrous glycerol at 4℃, 5 remained colourless and transparent, and 10 slightly yellowed while remaining transparent. Of the 15 bilayer lens scaffolds preserved in anhydrous glycerol at -20℃, none of the scaffolds yellowed, therefore, remaining colourless and transparent.<p>CONCLUSION: FS is a safe and non-toxic bio-gel. It can be used to glue Smile-derived corneal stromal lenses to construct corneal stromal scaffolds with good stability, high transparency and suitable hardness. Anhydrous glycerol at -20℃ is the best preservation condition for corneal stromal lens scaffolds.