ABSTRACT
Objective@#To describe the procedure for early corneal epithelial basement membrane(EBM) repair and regeneration in rabbits with corneal penetrating injury.@*Methods@#Forty-two New Zealand white rabbits were divided into modeling 1-, 3-, 5-, 7-, 14-, 21-, and 30-day groups using a random number table method, with 6 rabbits in each group; the right eyes were selected as the experimental eyes.Another 6 New Zealand white rabbits without any treatment were taken as the normal control group.A 2.0-mm trephine was used to ablate a full-thickness button of the central corneal tissue of each rabbit.The corneas were observed by slit lamp biomicroscopy at the respective time points after the trephined injury.Corneal epithelial fluorescein staining was used to evaluate re-epithelialization with Image J software and haze grading was evaluated with the Fantes classification.Hematoxylin-eosin staining was used to observe the healing process of the cornea.Transmission electron microscopy was conducted to assess the regeneration of the EBM and the reconstruction of the cornea.The study protocol was approved by the Ethics Committee of Guangxi Medical University (No.201811031). The use and care of the experimental animals complied with the Statement for the Use of Animals in Ophthalmic and Vision Research.@*Results@#The corneal epithelial fluorescein areas in modeling 1-, 3-, 5-, 7-, and 14-day group were (4.00±0.10), (3.11±0.10), (2.00±0.06), (0.90±0.04) and (0.67±0.03)mm2, respectively, with a significant difference among them (F=3 398.88, P<0.01). With the increasing of time after modeling, the corneal epithelium fluorescein area was gradually reduced, showing significant differences between any two groups (all at P<0.05), and the staining was disappeared at 21 and 30 days after modeling.The corneal haze grades were 3.44±0.53, 0.67±0.25, 1.33±0.50, 2.11±0.60, 2.44±0.53, 3.22±0.44 and 3.78±0.44 in modeling 1-, 3-, 5-, 7-, 14-, 21-, and 30-day group, respectively. The corneal opacity score gradually decreased during 1-5 days after modeling and gradually increased during 5-30 days after modeling, with a significant difference among them (F=51.182, P<0.01). Hematoxylin-eosin staining revealed that a fibrin clot formed in the wound area, and a single layer of epithelium covered the area at initial 3 days after modeling, and a large number of fibroblasts and some extracellular matrix were found at 5 days after modeling.At 21 and 30 days after modeling, the collagen fibers were tightly arranged in the anterior stroma.Transmission electron microscopy showed that the wound was filled with irregular collagen fibers and myofibroblasts.The stroma was remodeled at 21 days after modeling, and defective regeneration of the EBM was detected at 21 and 30 days after modeling.@*Conclusions@#Corneal fibrosis initiates after corneal penetrating injury in rabbits and gradually aggravates, the EBM regenerates defectively.
ABSTRACT
Objective To describe the procedure for early corneal epithelial basement membrane (EBM) repair and regeneration in rabbits with corneal penetrating injury.Methods Forty-two New Zealand white rabbits were divided into modeling 1-,3-,5-,7-,14-,21-,and 30-day groups using a random number table method,with 6 rabbits in each group;the right eyes were selected as the experimental eyes.Another 6 New Zealand white rabbits without any treatment were taken as the normal control group.A 2.0-mm trephine was used to ablate a full-thickness button of the central corneal tissue of each rabbit.The corneas were observed by slit lamp biomicroscopy at the respective time points after the trephined injury.Corneal epithelial fluorescein staining was used to evaluate re-epithelialization with Image J software and haze grading was evaluated with the Fantes classification.Hematoxylin-eosin staining was used to observe the healing process of the cornea.Transmission electron microscopy was conducted to assess the regeneration of the EBM and the reconstruction of the cornea.The study protocol was approved by the Ethics Committee of Guangxi Medical University (No.201811031).The use and care of the experimental animals complied with the Statement for the Use of Animals in Ophthalmic and Vision Research.Results The corneal epithelial fluorescein areas in modeling 1-,3-,5-,7-,and 14-day group were (4.00±0.10),(3.11±0.10),(2.00±0.06),(0.90±0.04) and (0.67 ± 0.03)mm2,respectively,with a significant difference among them (F =3 398.88,P ＜ 0.01).With the increasing of time after modeling,the corneal epithelium fluorescein area was gradually reduced,showing significant differences between any two groups (all at P＜0.05),and the staining was disappeared at 21 and 30 days after modeling.The corneal haze grades were 3.44±0.53,0.67±0.25,1.33±0.50,2.11±0.60,2.44±0.53,3.22±0.44 and 3.78±0.44 in modeling 1-,3-,5-,7-,14-,21-,and 30-day group,respectively.The corneal opacity score gradually decreased during 1-5 days after modeling and gradually increased during 5-30 days after modeling,with a significant difference among them (F =51.182,P＜0.01).Hematoxylin-eosin staining revealed that a fibrin clot formed in the wound area,and a single layer of epithelium covered the area at initial 3 days after modeling,and a large number of fibroblasts and some extracellular matrix were found at 5 days after modeling.At 21 and 30 days after modeling,the collagen fibers were tightly arranged in the anterior stroma.Transmission electron microscopy showed that the wound was filled with irregular collagen fibers and myofibroblasts.The stroma was remodeled at 21 days after modeling,and defective regeneration of the EBM was detected at 21 and 30 days after modeling.Conclusions Corneal fibrosis initiates after corneal penetrating injury in rabbits and gradually aggravates,the EBM regenerates defectively.
ABSTRACT
Density of corneal endothelium is commonly used by clinician to evaluate the function of corneal endothelium.The importance of dysfunction of this layer has not been received enough attention in routine clinical works.Recently,dysfunction of corneal endothelium due to the ocular diseases and corneal transplantation has been updated.Different types of glaucoma cause different degrees of damage to the corneal endothelium.Among them,the most serious damage to the corneal endothelium is acute angle closure glaucoma.Different treatment patterns of glaucoma damage to endothelium also have different features.The occurrence frequency,severity of the inflammation and the course of uveitis are the important factors which affect the corneal endothelium.The pathologic changes of pseudoexfoliation syndrome includes hypoxic changes in the anterior chamber,deposition of extracellular matrix in anterior segment and fibroblastic changes of the endothelium.These pathologic changes can decrease the endothelium function and the tolerance of injury.For keratoplasty,corneal immunologic rejection,surgical options,the primary disease and secondary late endothelial failure are the important factors of corneal endothelium dysfunction.Diabetes is a common systemic disease that cause corneal endothelium reserve capacity reduced.The decreasing of Na+/K+-ATPase activity,the accumulation of advanced glycation end products,constant metabolic stress can reduce corneal endothelium wound-healing ability.Recent researches of risk factors for corneal endothelium dysfunction were summarized in this paper to help clinician understand and value assess this element before intraocular surgery.