| Objective: To identify the efficacy and safety of early anterior chamber irrigation in the treatment of corneal alkali burn, to observe the effect and pathological changes of early anterior chamber washout on alkali burned cornea, to observe and evaluate the role of early anterior chamber washout on the synthesis and protein distribution of interleukin-1β(IL-1β)and transforming growth factor-β2(TGF- β2) on alkali burned cornea.Methods: 48 New Zealand white rabbits were randomized into 4 groups.The 16 right eyes in group A(n=16) were in the anterior chamber washout 2h after burn. The 16 right eyes in group B(n=16) were in the anterior chamber washout 12 h after burn.The16 right eyes in group C(n=16) were in the anterior chamber washout 24 h after burn.And 16 corneas were randomly selected from the 3 groups to serve as blank control(group D) with alkali burn and no washout was performed. Every 4 rabbits in all groups were sacrificed to obtain corneal tissue at 1d, 4d, 7d and 14 d.The corneal opacity, neovascularization, corneal epithelial were defected with slit lamp.The changes of the corneal structure were observed by in vivo confocal microscopy(IVCM); using Q-PCR to detect the expression of TGF-B2 and IL-1β in cornea, immunohistochemical method to observe distribution of the TGF-B2 and IL-1β. histopathological method to observe the pathological changes of the structure and the corneal inflammatory cell infiltration of the cornea.Results:1.The opacity scores of all alkali burned model had not significant difference between all groups in 0d(P>0.05); The scores of group A, B werelower than that of C,D in1, 4, 7, 14d(P<0.05),the scores of group A were lower than that of group B in7,14d(P<0.05). The group C and D had different haze score at 1,4,7,14d(P<0.05).2.Histopathological examinations:(1) HE stain of alkali burn corneal showed the corneal inflammation infiltration is dominated by polymorphonuclear leukocyte(PMN)(2)inflammatory cell infiltration and necrosis in group A,B,C was lower than that of group D, but the group A and group B had no significant difference.3.Immunohistochemical staining showed:1.IL-1β:(1) The IL-1 increased in alkali burned corneal tissue, mainly expressed in inflammatory cells, corneal epithelial basal cells and fibroblasts; The expression of IL-1β increased gradually with time,with sudden rise at 4d, the positive expression of14 d was highest in thecornea of group D.(2)The expression of IL-1βin group A was significantly lower than that of the untreated group and the group C at 7,14d(P<0.05);(3) In 1d, IL-1βexpression among the 4 groups in corneal tissue had not significant differences(P>0.05);at 4, 7, 10 d, IL-1βin group A, B, C were lower than that in D group(P<0.05), there was no significant difference in all time point of between group A and B.(P>0.05).2.TGF-β2:(1) The TGF- β2 increased in alkali burned corneal tissue, mainly expressed in the basal epithelial cells, cytoplasms, and fibroblasts, can also be found expression in the areas of epithelial proliferation and repairing matrix. The expression in the surrounding area was significantly higher than that in the injured central epithelium and stromal corneal. In the control group, TGF- β2 reached the peak at 7d, decreased at 14 d.(2)In group A, the expression was lower than the other three groups at 4,7,14d(P<0.05). The expression of TGF- β2 in group B,was lower than groupC and D.(P<0.05).4.Q-PCR indicated:1.IL-1β:(1) The expression of IL-1β gene in alkali burned cornea tissue increased gradually with time, suddenly rose at 4d, reached a peak in the 14 d.(2) In group A, the IL-1β reached the peak at 4d, then decreased, the expression was lower than that in group D at each time points(P < 0.05), and had significant difference with group C in 7,14 d,(P < 0.05), but had no significant difference with group B at different time points(P > 0.05).2.TGF-β2:(1) The expression of TGF-β2 gene in alkali burned corneal tissue increased gradually, reached a peak at 7d, decreased at 14d; group A in each time period were lower than group C,D(P<0.05), and had significant differences with group B at 7,14d(P<0.05), but the overall trend between the 2 groups had no significant difference.5.In vivo confocal microscopy showed:(1)After alkali burn,rabbit corneal epithelial cells swelled, part of the region can not see the epithelial cells,and punctate stromal inflammatory cells appeared at1 d.(2)At 4d,loss of rabbit corneal epithelial cells increased; the superficial stromal cell swelled with unclear boundary, and inflammatory cells increased; Endothelial cells had pleomorphic changes, with fuzzy boundary,and cell gap increased with loose connection, but no obvious inflammatory cell.(3)At 7d, rabbit corneal epithelium remain lossing; shallow stromal cell swelled,and inflammatory cells increased withoccasionally neovascular endothelial cells,but deep stromal cells decreased; the loss of endothelial cells can be observed.(4)At 14 d,stromal and epithelial can found scar formation, a large number of inflammatory cells can be seen in the matrix. In group A, no obvious loss of endothelial cells, stromal inflammatory cellswere significantly less than that in the control group.Conclusions:1.Early anterior chamber irrigation can reduce corneal alkali burn ulcer score and inflammatory necrosis, contribute to the epithelial healing and reducethe scar formation.2.Early anterior chamber irrigation had significant inhibitory effect on the IL-1βinthe alkali burned cornea, in order to reduce inflammation, inhibit ulcerous formation.3.The TGF- β2 in the corneal tissue mainly express in alkali burn repair period,may relate to early abnormal regeneration, early anterior chamber irrigation can inhibit its expression. |
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