整合素ανβ3在大鼠青光眼滤过术后结膜瘢痕形成中的作用

Effect of integrinανβ3 on conjunctival scar formation after glaucoma filtration surgery in rats

目的观察整合素ανβ3在大鼠青光眼滤过术后结膜瘢痕中的表达,探讨其在滤过术后瘢痕形成中的作用。方法选取SPF级6~8周龄雄性SD大鼠55只,取右眼建立大鼠青光眼滤过术动物模型,剔除建模失败的大鼠15只,采用随机单位组设计分组法将造模成功大鼠分为对照组、转化生长因子(TGF)组、LM609组和TGF+LM609组,每组10只,分别采用含质量分数0.9%氯化钠溶液、TGF-β2(2 mg/ml)溶液、整合素ανβ3受体阻断剂LM609(40μg/ml)溶液和TGF-β2(2 mg/ml)+LM609(40μg/ml)溶液的棉片术中处理结膜瓣2 min。分别于术前及术后3 d、1周、2周采用iCARE眼压计监测眼压,计算术后平均眼压比率(术后眼压/术前眼压×100%);于术后3 d、1周、2周采用裂隙灯显微镜拍照观察滤过泡形态改变,计算滤过泡生存比率;术后2周,摘取各组术眼眼球组织制备石蜡切片,分别采用苏木精-伊红染色和苦味酸-天狼星红染色观察手术区球结膜组织的炎性改变、纤维化程度及胶原纤维沉积情况;采用Western blot法检测整合素αν、整合素β3相对表达量;采用免疫组织化学染色法检测手术区结膜组织整合素ανβ3表达情况。结果各组大鼠术后第3天眼压均较术前明显降低,术后1~2周逐渐恢复至术前水平;对照组、TGF组、LM609组和TGF+LM609组平均眼压比率分别为(101.80±4.44)%、(103.90±5.65)%、(94.10±7.45)%和(100.60±4.61)%,总体比较差异有统计学意义(F=4.571,P=0.010),其中LM609组平均眼压比率均小于对照组、TGF组和TGF+LM609组,差异均有统计学意义(均P<0.05)。术后2周,对照组和TGF+LM609组滤过泡变为扁平状,球结膜组织稍有增厚;TGF组球结膜组织明显增厚,并有大量的血管长入;LM609组仍可见局限的小滤泡,血管化较其他各组明显减少。TGF组滤过泡生存比率明显低于对照组、LM609组和TGF+LM609组,LM609组滤过泡生存比率明显高于对照组和TGF+LM609组,差异均有统计学意义(均P<0.05)。术后2周,LM609组和TGF+LM609组结膜组织中炎性细胞浸润数量均较TGF组减少,胶原纤维沉积较TGF组疏松。TGF组手术区结膜组织中整合素αν、β3相对表达量明显高于对照组、LM609组和TGF+LM609组,差异均有统计学意义(均P<0.05)。免疫组织化学染色结果显示,整合素ανβ3阳性细胞主要集中在手术区及微管周围结膜组织,TGF组手术区结膜组织整合素ανβ3阳性表达细胞数量均较其他组明显增加。结论整合素ανβ3在大鼠滤过术后结膜组织瘢痕中高表达,抑制其表达可减少纤维沉积,延长滤过泡生存时间,提示整合素ανβ3可能参与结膜瘢痕形成过程。

Objective To investigate the expression of integrinανβ3 in conjunctival scar after glaucoma filtration surgery and to explore its role in the formation of filtering scar in rats.Methods Fifty-five SPF male SD rats aged 6-8 weeks were selected to establish the model of glaucoma filtration surgery,and 15 unsuccessful modeling rats were excluded.The remaining rats were divided into control group,transforming growth factor(TGF)group,integrinανβ3 receptor antagonist LM609 group and TGF+LM609 group,with 10 rats in each group.The conjunctival flap of different groups was treated with cotton piece containing 0.9%sodium chloride,TGF-β2(2 mg/ml),LM609(40μg/ml),TGF-β2(2 mg/ml)+LM609(40μg/ml)solution for two minutes,respectively,according to grouping.The intraocular pressure(IOP)was monitored with an iCARE tonometer before operation and at 3 days,1 week,2 weeks after operation,and the average IOP ratio([postoperative IOP/preoperative IOP]×100%)was calculated.At 3 days,1 week and 2 weeks after operation,slit lamp microscopy was used to observe the morphological changes of filtering blebs and calculate the survival rate of filtering blebs.Two weeks after operation,the operative eyeball tissues were removed and made into paraffin section.The inflammatory changes,fibrosis and collagen deposition of bulbar conjunctiva in the operation area were observed by hematoxylin-eosin staining and picric acid-sirius red staining,respectively.Western blot was used to detect the expression of integrinανandβ3.Immunohistochemical staining was used to detect the expression of integrinανβ3 in the conjunctival tissue of operation area.The use and care of the rats complied with the Instruction Notions with Respect to Care for Laboratory by State Ministry of Science and Technology.The study protocol was approved by an Ethics Committee of The Daping Hospital,Army Medical University(No.2017-06).Results The IOP of rats in each group was significantly decreased on the third day after operation compared with before operation,and gradually recovered to the preoperative level in the first to second week after operation.The mean IOP ratios of the control group,TGF group,LM609 group and TGF+LM609 group were(101.80±4.44)%,(103.90±5.65)%,(94.10±7.45)%and(100.60±4.61)%,respectively,showing a statistically significant difference among them(F=4.571,P=0.010).The mean IOP ratio of LM609 group was lower than that of the control group,TGF group and TGF+LM609 group(all at P<0.05).Two weeks after operation,the filter blebs became flat and the bulbar conjunctival tissue was slightly thickened in the control group and TGF+LM609 group,and bulbar conjunctival tissue was significantly thickened with a large number of blood vessels growing in the TGF group,and localized small filter blebs as well as less vascularization were seen in the LM609 group.The survival rate of filtering bleb in the TGF group was significantly lower than that in the control group,LM609 group and TGF+LM609 group,and the survival rate of filtering bleb in the LM609 group was significantly higher than that in the control group and TGF+LM609 group(all at P<0.05).Two weeks after operation,there were fewer infiltrated inflammatory cells and looser collagen fiber deposition in the conjunctival tissue in the LM609 group and TGF+LM609 group compared with the TGF group.The relative expression levels of integrinανandβ3 under conjunctival tissue in the TGF group were significantly higher than those in the control group,LM609 group and TGF+LM609 group(all at P<0.05).Immunohistochemical staining showed that integrinανβ3-positive cells were mainly in the conjunctival tissue around the operation area and microtubules.The number of integrinανβ3-positive cells in the conjunctival tissue of the operation area in the TGF group were significantly greater than those of other groups.Conclusions Integrinανβ3 is highly expressed in the scar of conjunctival tissue after filtering surgery in rats.The inhibition of integrinανβ3 can reduce the deposition of fibers and prolong the survival of filtering blebs,suggesting that integrinανβ3 may be involved in the formation of conjunctival scar.