| Research background:Corneal alkali burn is a common and intractable ocular injury.Corneal alkali burn can activate inflammation,oxidative stress,nerve regulation and other links,resulting in acute ocular surface inflammation and continuous corneal epithelial defects.Without timely and effective treatment,scars will be formed in the process of corneal healing and even corneal perforation,leading to permanent visual impairment.Therefore,it is of great significance to explore the new treatment methods of corneal alkali burn.Research objective:To investigate whether Edaravone,a novel oxygen free radical scavenger,has protective effect on alkali burn of cornea.Materials and Methods:Twenty-one New Zealand white rabbits were randomly selected as group A(blank group)after 1 week of adaptive feeding,and the left eye of all the other white rabbits was selected as group B(experimental group)and right eye as group C(control group).No treatment was given to both eyes of group A,and a second-degree corneal alkali burn model was established in groups B and C.After modeling,group B was given self-made Edaravone eye drops(0.3g/L)and levofloxacin eye drops 4 times a day,and group C was given normal saline and levofloxacin eye drops 4 times a day.Corneal edema,turbidity,neovascularization and corneal epithelial injury were observed daily by slit-lamp microscope in group B and group C immediately after burn until 14 days after burn.Dry eyes were evaluated by Schimmer I test and BUT test.Tears were taken at 1,3,5,7 and14 days after burn,respectively,and ferns were observed by smear.The conjunctiva was taken to observe goblet cell changes,and the cornea was taken to observe corneal tissue morphology,neural morphology and number changes.Apoptotic cells were detected by cell apoptosis in situ end labeling(TUNEL).Group A underwent the above inspection on the 14 th day after the modeling of group B and group C.Results:1.Corneal epithelial defect: The corneal epithelium was damaged by corneal alkali burn,which was gradually repaired in both the saline group and Edaravone group over time.Under slit lamp observation,the corneal epithelium of Edaravone group was repaired faster than that of normal saline group,but there was no statistically significant difference between the two groups according to CFS score(P > 0.05).However,HE staining showed that the corneal epithelium of the two groups gradually proliferated and thickened,and the corneal epithelium cells of the experimental group were more neatly arranged and had more layers than that of the control group at the 3rd,5th,7th and 14 th day after alkali burn.2.Corneal edema and turbidity: corneal edema and turbidity appeared immediately after alkali burn in the experimental group and the control group,and the corneal edema and turbidity increased significantly at the 1st and 3rd days after alkali burn,and gradually decreased at the 5th,7th and 14 th days,and the range was gradually narrowed,but there was no significant difference in the score of edema and turbidity between the two groups(P > 0.05).3.Neovascularization: On the third and fifth day after alkali burn,neovascularization networks gradually appeared in the corneal limbus of the experimental group and the control group,and gradually extended into the central region of the cornea.There was no significant difference between the two groups.On the 7th and 14 th day,corneal neovasculae in the two groups became longer and thicker,but gradually thinning,and the experimental group was shorter and thinner than the control group,but there was no statistical significance in corneal neovasculae score(P > 0.05).However,HE staining results showed that neovascularization was visible in the stromal layer of the experimental group and the control group on the 7th and 14 th day after alkali burn,and the neovascularization in the control group was thicker and more than that in the experimental group.4.Degree of dry eye: schimmer I showed no significant difference between the experimental group and the control group.The time of tear film rupture(BUT)showed no significant difference between the experimental group and the control group.The results of lacrimal fern test showed that the morphology of lacrimal fern was damaged by alkali burn of cornea,and it recovered gradually over time.The experimental group recovered faster and in better shape than the control group.The results of conjunctival goblet cells showed that the number of goblet cells in corneal alkali burn decreased significantly,and the number of goblet cells increased gradually with the passage of time.The number of goblet cells in the experimental group was significantly higher than that in the control group at each time point after alkali burn(P < 0.05).5.Corneal nerve gold chloride staining: the results showed that corneal alkali burn significantly damaged corneal nerves,over time,the experimental group and control group corneal nerves are gradually regenerated,but the control group nerve shape and number is slightly better than the experimental group.6.Apoptosis: TUNEL staining was used to evaluate the apoptosis of corneal cells after alkali burn.The results showed that a large number of apoptotic cells could be observed in the stroma and endodermis of cornea between the experimental group and the control group at day 1 and 3 after alkali burn,and there was no significant difference in the IOD value between the two groups(P > 0.05),which verified that alkali burn of cornea can promote apoptosis.At the 5th,7th and 14 th day after alkali burn,apoptotic cells in the two groups were significantly reduced and gradually migrated to the upper cortex,and the apoptotic cells in the experimental group were significantly reduced than those in the control group,and the IOD value was significantly different between the two groups(P <0.05).Conclusions:1.Edaravone can promote corneal epithelial repair and inhibit corneal neovascularization after alkali burn in rabbits.2.Edaravone can promote the formation of goblet cells in conjunctiva after alkali burn,improve the morphology of tear fern,and repair mucin-deficient dry eyes.3.Edaravone can promote the regeneration of corneal nerve after alkali burn.4.Edaravone inhibited apoptosis of corneal tissue after alkali burn. |
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