甘草甜素对角膜上皮损伤愈合中炎症反应的抑制作用

目的　探讨甘草甜素对角膜上皮损伤愈合中炎症反应的抑制作用。方法　取SPF级健康8周龄的雄性C57BL/6J小鼠60只，随机分为治疗组和对照组，每组30只，两组小鼠右眼建立角膜上皮损伤模型，左眼不做处理。治疗组用甘草甜素溶液滴眼，对照组用PBS滴眼，连续滴眼3 d。造模后0 h、24 h、48 h、72 h，使用100 g·L"^-1荧光素钠溶液染色观察两组小鼠的角膜上皮缺损面积；通过HE染色观察两组角膜组织结构变化；采用免疫组织化学染色法检测角膜基质层中白细胞介素-1（interleukin-1，IL-1）β的表达以及中性粒细胞的浸润情况。结果　造模后24 h、48 h、72 h，治疗组角膜上皮缺损率分别为（78.75±5.81）%、（21.58±4.53）%、（0.83±0.72）%，明显低于对照组的（87.74±3.57）%、（32.21±4.02）%、（3.80±1.86）%，差异均有统计学意义（均为P<0.01）。造模后72 h，HE染色结果显示:治疗组角膜上皮生长2～3层，上皮细胞排列欠规则；对照组角膜上皮生长0～2层，上皮细胞排列紊乱。造模后72 h，免疫组织化学染色结果显示:两组角膜基质层中IL-1β的阳性表达均降低，治疗组角膜基质层中IL-1β的平均光密度值为0.21±0.03，明显低于对照组（0.31±0.03），差异有统计学意义（P<0.01）。另外，造模后72 h，两组角膜基质层的中性粒细胞数量大幅度减少，治疗组为每200倍视野（10.66±5.13）个，较对照组［（40.00±6.08）个］明显减少，差异有统计学意义（P<0.01）。结论　角膜上皮损伤时，甘草甜素能有效降低角膜基质层中 IL-1β 的表达和中性粒细胞浸润，从而减轻炎症反应，促进角膜上皮愈合。

Inhibition of glycyrrhizin on inflammatory response in corneal epithelial wound healing

Objective　To investigate the inhibitory effect of glycyrrhizin on inflammatory reaction in corneal epithelial healing.Methods　Totally 60 SPF healthy 8-week-old male C57BL/6J mice were randomly divided into two groups:treatment group and control group,with 30 mice in each group.Corneal epithelial injury model was established in the right eyes of both groups,with the left eyes untreated.The treatment group was treated with glycyrrhizin and PBS eye drop for the control group for 3 days.At 0 h,24 h,48 h,and 72 h after modeling,the corneal epithelial defect area was observed by staining with 100 g·L^-1" fluorescein sodium solution.Additionally,HE staining was applied to observe the changes in corneal tissue structure in both groups;immunohistochemical staining was employed to detect the expression of interleukin-1 (IL-1) β in corneal stroma layer,as well as the infiltration of neutrophils.Results　At 24 h,48 h,and 72 h after modeling,the corneal epithelial defect rates in the treatment group were (78.75±5.81)%,(21.58±4.53)% and (0.83±0.72)%,respectively,which were significantly lower than those in the control group ［(87.74±3.57)%,(32.21±4.02)% and (3.80±1.86)%］,and the differences were statistically significant (all P<0.01).At 72 h after modeling,HE staining revealed that,in the treatment group,2-3 layers grew in the corneal epithelium with less regularly arranged cells,while in the control group,0-2 layer epithelium grew with disorderly arranged epithelial cells.At 72 h after modeling,immunohistochemical staining exhibited that the positive expression of IL-1β in the corneal stroma was decreased in both groups,and the mean optical density value of IL-1β in the corneal stroma of the treatment group was 0.21±0.03,which was significantly lower than that of the control group (0.31±0.03),and the difference was statistically significant (P＜0.01).In addition,the number of neutrophils in corneal stroma of the two groups was significantly reduced at 72 hours after modeling,and it was (10.66±5.13)cells per 200-fold field of view in the treatment group and the number was considerably lower than that of the control group ［(40.00±6.08)cells per 200-fold field of view］,the difference was statistically significant (P<0.01).Conclusion　After corneal epithelial injured,glycyrrhizin can effectively reduce the expression of IL-1 β and infiltration of neutrophils in corneal stroma,thus reducing inflammation and promoting corneal epithelial healing.