Background Pterygium is a relatively common eye disease,but its aetiology and pathogenesis remain uncertain.At present,the study on pterygia focuses on understanding its underlying mechanism.Objective This study was to detect the expression of 8-hydroxy-2'-deoxyguaine (8-OHdG),a marker of oxidative damage of DNA,and bcl-2,a gene related with apoptosis,on the pterygium tissue.Methods Thirty pterygium tissue specimens were obtained during the surgery with the primary pterygium 24 cases and recurrent pterygium 6 cases.In addition,20 normal conjunctival specimens from retinal detachment surgery and strabismus surgery were collected.The expressions of 8-OHdG and bcl-2 in pterygium tissue were detected using immunochemistry and compared with the normal conjunctival tissue.The difference in the expressions of 8-OHdG and bcl-2 among different specimens was compared by x2test,and the relationship between 8-OHdG expression and bcl-2 expression was evaluated by Kappa test.Results The positive expressing rate of 8-OHdG in the pterygium tissue was 62.5％ and 83.3％ in the primary and recrudescence pterygium tissue,respectively,but the expression of 8-OHdG was absent in the normal conjunctiva tissue.No significant difference was found in the positive expressing rate of 8-OHdG between primary and recrudescence pterygium tissue(x2 =0.938,P＞0.05).The bcl-2 expressing rate was 90.0％ and 87.5％ in the primary and recrudescence pterygium tissue,respectively.However,that in the normal conjunctival tissue was absent.No significant difference was seen in the bcl-2 expression rate between primary and recrudescence pterygium tissue (x2=0.833,P ＞ 0.05).Of the 27 pterygium tissue with bcl-2 positive expression,8-OHdG showed the positive expression in 20 specimens,and 3 specimens with the bcl-2 negative response were absent reactive to 8-OHdG,showing insignificant difference between them (P＞0.05).The relationship between 8-OHdG expression and bcl-2 expression was concord in a certein extent (Kappa =0.464).Conclusions The upregulation of 8-OHdG in the pterygium tissue indicates that oxidative damage of DNA plays a role in the development of pterygium.Oxidative damage of DNA caused by ultraviolet may be an upriver factor,which induces raising up of expression of bcl-2 and inhibits the apoptosis of normal cells and further proliferation of the conjunctiva tissue,resulting in the genesis and development of pterysium.%背景 翼状胬肉是人眼表常见疾病,其确切的病因尚未明确,有关翼状胬肉发病机制的研究仍是临床关注的重点. 目的 检测DNA氧化损伤标志物8-羟基脱氧鸟苷(8-OHdG)和凋亡相关基因bcl-2在翼状胬肉和正常结膜组织中的表达,探讨DNA氧化损伤在翼状胬肉发病机制中的可能作用.方法 在翼状胬肉切除手术中收集30例翼状胬肉组织标本,其中原发性翼状胬肉标本24例,复发性翼状胬肉标本6例.另收集行视网膜脱离手术、斜视手术和上睑下垂手术的正常球结膜标本20例.免疫组织化学法检测翼状胬肉标本中8-OHdG和bcl-2的表达,并与正常球结膜组织的标本进行对照.用卡方检验法比较各组标本中8-OHdG和bcl-2阳性表达的差异,用Kappa一致性检验评价翼状胬肉组织中8-OHdG和bcl-2阳性表达的一致性. 结果 原发性和复发性翼状胬肉组织中8-OHdG的阳性表达率分别为62.5％和83.3％,而正常结膜组织中8-OHdG无表达；原发性和复发性翼状胬肉组织中8-OHdG阳性表达率的比较差异无统计学意义(x2=0.938,P＞0.05).原发性和复发性翼状胬肉组织中bcl-2的阳性表达率分别为90.0％和87.5％,而正常结膜组织中bcl-2无表达；原发性和复发性翼状胬肉组织中bcl-2的阳性表达率差异无统计学意义(x2=0.833,P＞0.05).27例bcl-2阳性的翼状胬肉标本中有20例8-OHdG呈阳性表达(20/27),3例bcl-2阴性的翼状胬肉标本8-OHdG均呈阴性表达,二者的表达结果差异无统计学意义(P＞0.05).翼状胬肉标本中8-OHdG与bcl-2的表达一致性一般(Kappa=0.464). 结论 翼状胬肉组织中8-OHdG呈阳性表达,提示DNA氧化损伤在翼状胬肉的发病机制中有一定作用,紫外线所致的DNA氧化损伤可能作为上游的因素,导致凋亡相关基因bcl-2的增高,从而抑制了正常的细胞凋亡,造成组织细胞的过度增生,导致了翼状胬肉的发生和发展.
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