重组胸腺素β4调节NF-κB表达促进兔角膜碱烧伤后修复

Recombinant Thymosin β4 regulate corneal nuclear factor κB expression after rabbit corneal alkali injury

目的:探讨重组胸腺素β4(Thymosin β4,Tβ4)对角膜碱烧伤后角膜核转录因子κB(nuclear factor κB,NF-κB)表达的影响和促进角膜愈合的观察。方法:用1mol/LNaOH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。动物随机分为实验组和对照组,实验组给予低中高剂量(0.1,1,10μg/50μL)Tβ4,对照组给予PBS(阴性对照组)和rh-EGF(阳性对照组)皆2次/d滴眼。烧伤后1,3,7,14d肉眼观察角膜烧伤面积的变化,照相、统计愈合率;免疫组化染色检测NF-κB和IL-1β表达;取烧伤区角膜组织匀浆液提取细胞核蛋白,用ELISA检测NF-κB的p65亚基表达水平。结果:角膜碱烧伤后Tβ4用药组角膜愈合率最高达到33.8%,相应阴性对照组为22.8%,Tβ4用药组显著高于对照组(P<0.01),其中中剂量Tβ4组愈合率高于其他剂量组;Tβ4用药组NF-κB免疫组化染色积分吸光度明显低于对照组(P<0.05),ELISA检测NF-κB的p65亚基,在Tβ4用药组中表达最少(P<0.01),IL-1β免疫组化染色阳性,但实验组和对照组差异无统计学意义。结论:重组Tβ4促进角膜碱烧伤修复,其机制可能与下调NF-κB在细胞核内的表达相关。

AIM： To investigate the ability of Thymosin β4 （Tβ4） to promote healing in an alkali injury model in vivo and the mechanisms involved in that process which Tβ4 may be a potential anti-inflammation agent in this model. METHODS： Corneas of the New-Zealand Rabbit were chemically burned with a 6mm disc soaked in 1mol/L NaOH for 30 seconds. Eyes were irrigated copiously with saline and then treated topically with PBS（Negative control group）, rh-EGF（jinyinshu drop, Positive control group）, and Tβ4 （0.1, 1, 10μg/50μL） twice daily. At the time point of 1 day, 3, 7, 14 days postburn, the healing rate of the cornea were examined and MMP-2, TIMP-2, VEGF immunostaining performed.RESULTS：Tβ4-treated corneas demonstrated improved cornea healing rate of 33.8% vs PBS-treated corneas of 22.8%（P〈0.01） , 1μg/50μL Tβ4 seemed to be the best dosage. Whereas immunohistochemistry result suggested that Tβ4 decreased corneal NF-κB expression（P〈0.01） after alkali injury, no change in IL（ interleukin） -1β was detected（P〉0.05）. The enzyme linked immunosorbent assay （ELISA） result suggested that theres a significant decrease to the NF-κB protein levels（P〈0.01）. CONCLUSION： Tβ4 treatment decreases corneal inflammation and inhibits the expression of NF-κB to improve cornea healing. The result have important clinical implications for the potential role of Tβ4 as a corneal anti-inflammatory agent.KEYWORDS： alkali injury; wound healing; Thymosin beta4; nuclear factor-kappa B; interleukin-1β