MK2抑制剂PF-3644022对视网膜分支静脉阻塞模型大鼠的治疗作用

目的　探讨MK2抑制剂PF-3644022对视网膜分支静脉阻塞（BRVO）模型大鼠的治疗作用。方法　通过激光光凝建立BRVO模型大鼠，将BRVO模型大鼠随机分为5组（n=12）:对照组、模型组、低剂量组、中剂量组和高剂量组。低、中和高剂量组大鼠分别按1 mg·kg^-1、5 mg·kg^-1、10 mg·kg^-1给予2 mL丝裂原活化蛋白激酶激活的蛋白激酶2（MK2）抑制剂PF-3644022灌胃，对照组和模型组大鼠给予2 mL蒸馏水或生理盐水灌胃，共治疗21 d。分别在治疗后1 d、7 d和14 d进行眼底照相、光学相干断层扫描(OCT)和荧光素眼底血管造影(FFA)检查，利用苏木精-伊红（HE）染色观察各组大鼠视网膜变化，采用免疫荧光染色及Western blot检测各组大鼠视网膜组织中MK2、p-MK2和血管内皮生长因子-α（VEGF-α）的表达。结果　HE染色、眼底照相、FFA和OCT检查结果均显示，MK2抑制剂PF-3644022以剂量依赖性方式减轻BRVO模型大鼠视网膜水肿、血管排列紊乱和收缩、视盘陷凹消失等病理现象。Western blot检测结果显示，治疗后1 d，与模型组（1.00±0.05）相比，低剂量组（0.75±0.04）、中剂量组（0.52±0.03）和高剂量组（0.43±0.02）大鼠视网膜组织中VEGF-α蛋白的相对表达水平均显著降低，并呈剂量依赖性降低（均为P<0.05）；治疗后21 d，各组大鼠视网膜组织中VEGF-α蛋白的表达均无明显差异（均为P>0.05）。治疗后1 d和21 d，与模型组（1.00±0.05、1.00±0.06）相比，低剂量组（0.51±0.03、0.47±0.02）、中剂量组（0.26±0.01、0.23±0.01）和高剂量组（0.22±0.01、0.21±0.01）大鼠视网膜组织中MK2蛋白的磷酸化水平均显著降低，并呈剂量依赖性降低（均为P<0.05）。结论　MK2抑制剂PF-3644022通过减轻视网膜水肿、调节VEGF-α蛋白的表达、抑制MK2活性等作用对BRVO动物模型发挥治疗作用。

Therapeutic effect of MK2 inhibitor PF-3644022 on rats with branch retinal vein occlusion

Objective　To investigate the therapeutic effect of MK2 inhibitor PF-3644022 on model rats with branch retinal vein occlusion (BRVO).Methods　The BRVO model rats created by laser photocoagulation were randomly divided into 5 groups (n=12): control group, model group, low dose group, medium dose group, and high dose group. Rats in the low, medium and high dose groups were given 2 mL of 1 mg·kg^-1, 5 mg·kg^-1 and 10 mg·kg^-1 MK2 inhibitor PF-3644022 by gavage, while rats in the control group and model group were given 2 mL of distilled water or normal saline by gavage. All rats were treated for 21 days. Fundus photography, optical coherence tomography (OCT), and fundus fluorescein angiography (FFA) were performed on the 1st, 7th and 14th day of treatment, respectively. Retinas were observed by hematoxylin and eosin (HE) staining. The expression levels of MK2, p-MK2 and vascular endothelial growth factor-α (VEGF-α) in retinal tissues were detected by immunofluorescence staining or Western blot.Results　The results of HE staining, fundus photography, FFA, and OCT all confirmed that the MK2 inhibitor PF-3644022 reduced model rats’ retinal edema, vascular arrangement disorder and contraction, excavation and disappearance of the optic disc in a dose-dependent manner. Western blot showed that after one day of treatment, compared with the model group (1.00±0.05), the expression levels of VEGF-α in the retinal tissues of rats in the low dose group (0.75±0.04), medium dose group (0.52±0.03) and high dose group (0.43±0.02) were significantly reduced in a dose-dependent manner (all P<0.05). However, after 21 days of treatment, there were no significant differences in the expression of VEGF-α among all groups (all P>0.05). On the 1st and 21st day of treatment, compared with the model group (1.00±0.05, 1.00±0.06), the phosphorylation levels of MK2 protein in the retinal tissues of rats in the low dose group (0.51±0.03, 0.47±0.02), medium dose group (0.26±0.01, 0.23±0.01) and high dose group (0.22±0.01, 0.21±0.01) were significantly reduced in a dose-dependent manner (all P<0.05).Conclusion　MK2 inhibitor PF-3644022 can treat BRVO animals by reducing retinal edema, regulating the expression of VEGF-α, and inhibiting MK2 activity.