大鼠角膜碱烧伤后视网膜细胞凋亡的研究

目的研究严重眼前段碱烧伤后视网膜组织内的细胞凋亡情况,以及Fas抗原(Fas)和Fas配体(Fas ligand,FasL)表达与细胞凋亡的关系。方法制作大鼠角膜严重碱烧伤模型。在烧伤的不同阶段,应用TUNEL法检测凋亡细胞、免疫组织化学法检测Fas、FasL在视网膜组织中的表达和变化,并与正常大鼠相对照。结果正常视网膜中基本未见TUNEL阳性细胞,碱烧伤3d后在视网膜神经节细胞、内核层细胞和内层血管内皮细胞中均可见不同程度的TUNEL阳性细胞。正常视网膜未见Fas表达,实验各组中均可见不同程度的Fas表达;正常视网膜FasL弱表达,实验各组FasL表达显著增强,与正常对照组比较差异有显著性(P<0.01)。Fas和FasL表达与凋亡之间具有较好的相关性,相关系数分别为0.899(P<0.01)和0.504(P<0.01)。结论严重眼前段碱烧伤后视网膜组织细胞存在异常凋亡,凋亡可能与Fas/FasL系统有关。

Study on apoptosis in the retina after severe alkali burn of the cornea in rats

Objective To observe whether apoptosis was involved in the retina after severe corneal alkali burn,and wheter it was associated with expression of Fas antigen(Fas) and Fas ligand(FasL).Methods The models of severe corneal alkali burns were induced in rats while normal rats as control group.Histologic sections of paraffin-embedded retinas at different time points after corneal burns were stained by TUNEL method for detection of apoptosis and by immunohistochemical technique for detection of Fas and FasL.Results TUNEL positive cells were not found in normal retina.A higher number of TUNEL positive cells in the vascular endothelium and the ganglion cell and inner nuclear layers was observed on the 3rd,7th,15th,and 30th day after alkali burn.Positive immunolabeling for Fas protein was not found in normal retina.The Fas expression in the retina was gradually increased from 1 to 7 days after alkali burn,and maintained on a relatively high level.FasL was expressed in normal retina.The FasL expression after alkali burn was significantly higher than that(P<0.01)in the control group.Analyzed with the correlation coefficient,there was a remarkable positive correlation between TUNEL positive cells and Fas(r_1=0.899,P<0.01) or FasL(r_2=0.504,P<0.01)in the retina after alkali burn.Conclusion Apoptosis exists in the inner retina after severe alkali burn of cornea in rats.It may be associated with prominent Fas and FasL expressions in the retina.