眼缺血综合征大鼠视网膜Bcl-2和Bax的表达

摘要

Objective To tell the difference of Bcl-2 and Bax expression on the retina between the ocular ischemic syndrome group and the sham group.Methods Experimental study.To establish the ocular ischemic syndrome model by bilateral common carotid arteries obliteration (BCCAO) in BN rats.Twenty BN rats were divided into two groups randomly: 12 in the model group and 8 in the sham group.In model group, midline incised in the neck and bilateral common carotid artery obliterated.While in the sham group, midline incised in the neck with no obliteration.Pupillary reflex were detected in both groups.After 1month, rats underwent fundus fluorescein angiography (FFA) examination.Optical coherence tomography (OCT) was used to measure and tell the retina thickness difference in both groups.Expression of Bcl-2 and Bax on rat retina and change of the Bcl-2/Bax ratio were detected by immunohistochemical staining.Chisquare test was used for classification variable, two independent samples T test was used for quantitative data.Results Compared to the sham group, only 1 eye of BCCAO group maintained its direct pupillary reflex, other eyes of the group appeared either lost or weakened their direct pupillary reflex.However, all rats in the sham group maintained their pupillary reflex.FFA showed that in the BCCAO group, retinal circulation time was significantly longer than it was in the sham group (aterial phase: t=6.19, P＜0.01;arteriovenous phase: t=8.24, P＜0.01;venous phase: t=2.73, P＜0.05).And in the model group, the background choroidal patchy hypofluorescence and typical arterial forward phenomenon in the early phase of arterial time were observed.OCT showed that in the model group, an obvious decrease of the thickness of neuroepithelial layer of retina was observed, which was (195.67±8.84) μm in the model group and (219.31±6.92) μm in the sham group.It had statistically significant difference (P＜0.05).Immunohistochemical staining results showed imbalance of Bcl-2, Bax expression on rat retina.Compared with the sham group,expression level of bax which was (5.67±0.84) μm in the model group was significantly increased (P＜0.05),while it was (2.34±0.57) μm in the sham group.There was no significant difference (P＞0.05) in Bcl-2expression in both groups, which was (5.61±0.98) μm in the model group and which was (5.63±0.88) μm in the sham group.And Bcl-2/Bax ratio was obsened statistically significant decreased (P＜0.05) in the BCCAO group compared with that in the sham group, which was (1.01 ±0.23) in the model group, and which was (2.47±0.47) in the sham group.Conclusions BCCAO of rats lead to the injury of retina function, diminish of retinal thickness, imbalance of Bax and Bcl-2 expression.%目的 比较眼缺血综合征(OIS)大鼠模型组与假手术组视网膜中Bcl-2、Bax表达的差异.方法 实验研究.采用双侧颈总动脉结扎(BCCAO)法建立BN大鼠OIS模型.采用随机分组法分别将大鼠分为模型组(12只)和假手术组(8只).模型组做颈部正中切口,结扎双侧颈总动脉,假手术组仅做颈部正中切口,不结扎血管.观察两组大鼠瞳孔对光反射,对术后1个月的大鼠行FFA检查并用OCT测定两组大鼠的视网膜神经上皮层厚度,观察其视网膜厚度的差异.免疫组织化学法测量并比较两组大鼠视网膜Bcl-2、Bax的表达以及Bcl-2/Bax比值的变化.分类变量采用X2检验,计量资料的比较采用两独立样本的t检验.结果 模型组大鼠双眼直接对光反射消失或迟钝,仅1只大鼠表现为单眼对光反射灵敏.假手术组大鼠双眼对光反射均存在.FFA检查:模型组大鼠视网膜循环时间较假手术组明显延长(动脉期:t=6.19,P＜0.01;动静脉期:t=8.24,P＜0.01;静脉期:t=2.73,P＜0.05),模型组大鼠观察到早期脉络膜的斑片状充盈以及典型的"动脉前锋"现象.OCT检查:模型组视网膜神经上皮层厚度[(195.67±8.84)μm]小于假手术组[(219.31±6.92)μm],差异有统计学意义假手术组(P＜0.05).免疫组织化学检查:与假手术组[(2.34±0.57)μm]相比,模型组Bax表达升高[(5.67±0.84) μm,P＜0.05),Bcl-2表达无明显差异[模型组(5.61±0.98)μm,假手术组(5.63±0.88)μm,P＞0.05)],Bcl-2/Bax比值降低[模型组(1.01 ±0.23) μm,假手术组(2.47±0.47) μm,P＜0.05)].结论 BCCAO法建立的模型组大鼠视网膜功能损伤,视网膜厚度变薄,凋亡相关因子Bax、Bcl-2表达失衡.