摘要目的 观察0.2%酒石酸溴莫尼定对视神经夹挫伤大鼠视网膜形态及bcl-2/bax表达的影响,探讨其作用机制.方法 雌性SD大鼠90只随机分为正常组、模型组、治疗组,每组30只.60只大鼠用视神经钳夹法制作SD大鼠视神经夹挫伤模型,治疗组30只鼠给予0.2%酒石酸溴莫尼定点眼,于实验的l、3、5、7、14、21 d处死大鼠,用苏木精-伊红染色计数各组鼠视网膜神经节细胞(RGCs)的数量,用透射电镜观察和比较各组鼠视网膜的超微结构改变,免疫组织化学染色检测鼠视网膜中bcl-2及bax的表达.结果 正常组视网膜结构正常,治疗组较模型组视网膜形态损伤减轻.造模后3～21 d,模型组和治疗组较正常对照组RGCs数量明显减少(P<0.05),但治疗组较模型组RGCs数量明显增加(P<0.01).造模后5～7 d,治疗组bcl-2在鼠视网膜中的表达量较模型组明显增加(P<0.01),但bax表达量明显减少(P<0.01).模型组和治疗组的bcl-2在鼠视网膜中的表达量较正常组增加但bax表达量明显减少(P<0.05).结论 0.2%酒石酸溴莫尼定对大鼠视神经夹挫伤有一定的治疗作用,其机制与抑制凋亡有关.

abstractsObjective Present study aimed to research the mechanism of the use of 0.2% brimonidine tartrate eye drops in the treatment of optic nerve crush injury of rat.MethodsAnimal models of optic nerve crush injury were created in 60 SD female rats by clipping the exposed optic nerve at 2 mm in retrobulbar for 6 seconds with 78 grams of reverse forceps.The successful model was identified as Marcus-gun pupil without bleeding of fundus after operation.The animals were randomly assigned to model group and brimonidine treating group,and another 30 normal SD rats were used as the normal control group.The 0.2% brimonidine tartrate eye drops was topically administered at 2 hours before operation and after operation twice per day in the brimonidine treating group.The retinas from 18 rats were isolated after 3,7,21 days for RGCs counting by H&E staining,and the retinal ultrastructure was examined under the transmission electron microscope.The retinas from the other 72 SD rats (including normal,model and brimonidine groups) were prepared for the detection of bcl-2 and bax using immunohistochemistry l,3,5,7,14,21 days after the operation.ResultsNormal and almost normal retina structure was exhibited in rats of the normal group and brimonidine treating group,but disorder of cellular arragement and decrease of retinal thickness were found in the model rats under the optical microscope.The RGCs counting was significantly different among the three groups from 3 days through 21 days after operation with the considerably declination in the model group and brimonidine treating group compared with the normal control group (P＜0.05-0.01).However,that of the brimonidine treating group was obviously increased in comparison with the model group (P＜0.01).The expression of bax in rat retina was obviously reduced (P＜0.01),but the expression of bcl-2 was increased in brimonidine group compared with the model group from 5 through 7 days after operation (P＜0.01).ConclusionThe 0.2% brimonidine tartrate eye drops has a preventive effect on optic nerve crush injury of rat,and its inhibition on apoptosis is one of the mechanisms.