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目的探讨重组胸腺素β4(thymosinβ4,Tβ4)调节基质金属蛋白酶2(matrix metalloproteinase-2,MMP-2)、组织金属蛋白酶抑制剂-2(tissue inhibitor of matrix metalloproteinase-2,TIMP-2)、血管内皮生长因子(vascular endothelial growth factor,VEGF)表达及促进兔角膜碱烧伤愈合的作用机制。方法用40g.L-1NaOH浸透的6mm直径圆滤纸片贴于兔角膜中央30s,建立兔角膜碱烧伤模型。60只健康成年新西兰白兔随机分为实验组和对照组,实验组每天2次分别给予低剂量(0.002g.L-1)、中剂量(0.02g.L-1)、高剂量(0.2g.L-1)Tβ4,对照组每天2次分别给予PBS(阴性对照组)和rh-EGF(金因舒滴眼液,阳性对照组)滴眼。分别于角膜碱烧伤后第3天、第5天、第7天、第9天、第11天观察角膜烧伤面积的变化,并统计角膜愈合率;分别于角膜碱烧伤后第1天、第3天、第7天、第14天免疫细胞化学染色检测MMP-2、TIMP-2和VEGF表达。结果在角膜碱烧伤后第11天,实验组高剂量Tβ4组角膜愈合率最高达33.76%,阴性对照组为22.69%,阳性对照组为21.38%,实验组高于阳性对照组(P<0.01或P<0.05),其中中剂量Tβ4组角膜碱烧伤后第3天、第5天、第7天、第9天角膜愈合率高于其他剂量组,但差异均无统计学意义(均为P>0.05)。免疫细胞化学显示早期(第1天和第3天)各组MMP-2表达差异无统计学意义(P>0.05),后期(第7天和第14天)实验组较阴性对照组明显升高,差异均有统计学意义(P<0.05或P<0.01)。TIMP-2在各时期组间比较,差异均无统计学意义(均为P>0.05);在角膜碱烧伤后第14天时,rh-EGF阳性对照组平均积分光密度染色最深,实验组染色明显弱于rh-EGF阳性对照组。结论重组Tβ4可能是通过调节MMP-2和TIMP-2的表达,影响二者的平衡,协同调节多种因子促进新生组织重塑,促进角膜碱烧伤修复。
Objective To investigate the effect of thymosin β4 (Tβ4) on the expression of matrix metalloproteinase-2 (MMP-2), tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) The mechanism of vascular endothelial growth factor (VEGF) expression and promotion of corneal alkali burn healing in rabbits. Methods Rabbit corneal alkali burn model was established with 40g.L-1NaOH saturated 6mm diameter circular filter paper attached to the central cornea of rabbit for 30s. Sixty healthy adult New Zealand white rabbits were randomly divided into experimental group and control group. The experimental group was given low dose (0.002gL-1), middle dose (0.02gL-1) and high dose (0.2gL-1) , And the control group was given PBS (negative control group) and rh-EGF (Jin Yin Shu eye drops, positive control group) twice a day. The change of corneal burn area was observed on the 3rd day, the 5th day, the 7th day, the 9th day and the 11th day after corneal alkali burn, and the corneal healing rate was calculated. On the 1st, 3rd, Day, day 7, day 14, immunocytochemical staining was used to detect the expression of MMP-2, TIMP-2 and VEGF. Results On the 11th day after corneal alkali burn, the healing rate of high dose Tβ4 group was up to 33.76%, 22.69% in negative control group and 21.38% in positive control group, which was higher in experimental group than in positive control group (P <0.01 or (P <0.05). The corneal healing rate of the 3rd day, 5th day, 7th day and 9th day after the middle dose Tβ4 corneal alkali burn was higher than other dose groups, but the differences were not statistically significant (P> 0.05). Immunocytochemistry showed that the expression of MMP-2 in each group had no statistical significance (P> 0.05) in the early stage (day 1 and day 3), but significantly increased in the experimental group (day 7 and day 14) compared with the negative control group , The differences were statistically significant (P <0.05 or P <0.01). There was no significant difference in TIMP-2 between the two groups (all P> 0.05). On the 14th day after corneal alkali burn, the average integral optical density of rh-EGF positive control group was the most stained, and the experimental group stained obviously Weaker than rh-EGF positive control group. Conclusion Recombinant Tβ4 may affect the balance of both by regulating the expression of MMP-2 and TIMP-2. Synergistic regulation of many factors may promote the remodeling of neonatal tissue and promote the repair of corneal alkali burn.