| Purpose:Alkali burn damages the microenvironment of cornea and leads to the destruction or dysfunction of limbal stem cells,delaying the repairment of corneal injury.This article aims to evaluate the effects of vitamin C in the treatment of cornea alkali burn and provide experimental basis for clinical treatment.Methods:There were 45 BALB/c mice in total.Five mice were randomly selected as a normal control group.Forty mice were randomly selected to establish alkali burn models with their right eyes and then divided into two groups（20 mice in each group）.One group was an experimental group.Vitamin C eye drops（concentration:10%,qh）and intraperitoneal injection（50 mg/kg,qd）were given daily for 7 days after alkali burn.The other group was a control group,which was given sterile saline eye drops（0.9%Na Cl,qh）for 7 days.The clinical evaluations（corneal fluorescent staining,corneal opacity and neovascularization）were detected on days 1,4,7 and 10 using slit lamp microscopy after corneal alkali burn.At the same time,global specimens were processed for immunofluorescent staining of myeloperoxidase（MPO）、the limbal stem cells markers p63 and proliferating cell nuclear antigen（PCNA）、the corneal epithelial markers cytokeratin3（CK3）、marker of myofibroblastsα-smooth muscle actin（α-SMA）and marker of blood vessels platelet endothelial adhesion molecule（PECAM-1,CD31）.Results:1.On day 1 after alkali burn,the corneal epithelium of mice was damaged and exfoliated,and the corneal fluorescein staining was positive.On day 10 after alkali burn,corneal epithelial regeneration was completed in Vc group.The corneal epithelial defect scores were significantly lower than that of the control group（0.80±0.20 vs 1.90±0.33,P=0.022）.Meanwhile,the corneal opacity of Vc group was significantly improved.The corneal opacity scores were lower than that of the control group（1.40±0.40 vs 3.00±0.44,P=0.029）.After alkali burn,the corneal neovascularization in the control group gradually grew into the central cornea.Corneal neovascularization was not found in Vc group.The corneal neovascularization scores in Vc group were lower than that in the control group on day 7 and day 10（1.00±0.32 vs 2.20±0.20,P=0.013 on day 7;0.60±0.25 vs 1.80±0.20,P=0.005 on day 10）.2.HE staining showed the central corneal epithelial defect on day 1 after alkali burn.The corneal epithelium in Vc group was completely repaired on day 10 and the corneal epithelium of the control group still had defects.Immunohistochemical staining showed that the number of p63 positive cells per field（×400）in Vc group on days 4,7 and 10 after alkali burn were:16.33±0.88、19.67±1.45、28.67±1.86,and the control group were:10.33±0.88、13.00±1.16、14±1.16.The number of p63 positive cells in Vc group were significantly higher than that in the control group（P=0.010 on day 4,P=0.023 on day 7,P=0.003 on day 10）.The number of PCNA positive cells per field（×400）in Vc group on days 4,7 and 10 after alkali burn were:17.33±1.20、21.33±1.20、33.33±2.60,and the control group were:9.00±1.16、14.33±1.45、19.00±1.53.The number of PCNA positive cells in Vc group were significantly higher than that in the control group（P=0.008 on Day 4,P=0.021 on Day 7,P=0.009 on Day 10）.On day 10 after alkali burn,the mean density of CK3 in Vc group was 0.1001±0.0075,the control group was 0.0512±0.0070.The expression of CK3 in Vc group was significantly higher than that in the control group（P=0.009）.3.On days 4,7 and 10 after alkali burn,the Vc group had less infiltration of inflammatory cells in the central cornea.The mean density of MPO in central cornea were significantly lower than that of the control group(1.40×10-4±6.32×10-5 vs4.90×10-4±8.14×10-5,P=0.027 in day 4;4.09×10-5±1.97×10-5 vs2.33×10-4±4.57×10-5,P=0.018 in day 7;6.20×10-6±3.64×10-6 vs5.69×10-5±9.79×10-6,P=0.008 in day 10).4.On days 7 and 10 after alkali burn,the number of CD31-positive neovascularization in Vc group were less than that in the control group（4.67±0.89vs 12.33±0.89,P=0.004 in day 7;6.33±1.45 vs 16.33±0.88,P=0.004 in day 10）.On day 10,the mean density ofα-SMA in Vc group was significantly lower than that in the control group(1.55×10-4±3.47×10-5 vs 3.76×10-4±4.54×10-5,P=0.018).Conclusions:Vitamin C could promote corneal epithelial repair after alkali burn,reduce corneal neovascularization and corneal opacity,and ameliorate corneal inflammation response induced by alkali burn.This provides experimental evidence for the application of vitamin C in corneal alkali burn treatment. |
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