β趋化因子受体CCR1在遗传性视网膜变性小鼠视网膜中的表达

Expression of β-chemokine receptor CCR1 in the retina of inherited retinal dystrophy mice

目的探讨β趋化因子主要的受体之一β趋化因子受体1(CCR1)在视网膜变性模型小鼠(rd小鼠)的视网膜变性过程中的表达及其在感光细胞凋亡中的病理作用。设计实验研究。研究对象出生后8、10、12、14、16及18天的rd小鼠各10只(共60只)及同龄C57BL/6N对照小鼠各10只(共60只)。方法小鼠断颈处死,取双眼眼球制作冰冻切片或分离新鲜视网膜组织。逆转录多聚酶链反应(RT-PCR)测定各鼠龄rd小鼠及对照鼠视网膜CCR1mRNA的表达水平。免疫组织化学法观察CCR1蛋白在各鼠龄rd小鼠视网膜的定位表达。CCR1在感光细胞及凋亡细胞中的表达由免疫荧光双标法确定。主要指标视网膜CCR1mRNA及蛋白的表达、CCR1的细胞定位及与凋亡细胞的关系。结果 CCR1mRNA在对照组及各鼠龄rd小鼠视网膜中均有表达,但在出生后12、14天rd小鼠视网膜中表达明显升高(光密度值分别为0.986±0.17和1.152±0.22,P=0.010和0.008)。CCR1阳性染色细胞开始出现于出生后8天的rd视网膜外核层,并于12及14天达到高峰。对照组视网膜外核层无CCR1阳性染色。CCR1与视紫红质、CD11b或TUNEL染色免疫荧光双标结果显示,CCR1表达于感光细胞而非小胶质细胞中,部分CCR1表达于凋亡的感光细胞中。结论在rd小鼠视网膜中CCR1表达于感光细胞并随其变性程度加重表达升高。CCR1的活化可能在rd小鼠感光细胞凋亡中发挥作用。(眼科,2013,22:383-388)

Objective To investigate the expression of C-C chemokine receptor 1 （CCR1）, a major chemokine receptor for β-chemokines, in the ratina of rd （retinal degeneration） mice and further explore its role in the photoreceptor degeneration. Design Ex- perimental study. Partreipants Sixty rd mice at postnatal days （P） 8, 10, 12, 14, 16 and 18 day （10 mice each） and 60 C57BL/6N con- trol mice with the matcholde age （10 mice each）. Methods The expression levels of CCRlmRNA in the whole control rd mice were de- termined by RT-PCR assay. Location of CCR1 in the retina were studied by immunohistochemical analysis. Expression of CCR1 in the photoreceptor ceils and apoptotic cells was determined by double labeling. Main Outcome Measures Expression of CCRlmRNA and CCR1 protein, cellular location of CCR1 and its relation to the apoptotic cells. Results Expression of CCRlmRNA was noted in both control and rd mice retinas at each age group, but was markedly increased in the rd mice retinas at P12 and P14 day. CCRl-positive cells started to emerge in the rd mice retina at P8 day and reached a peak at P12 and P14 day. Double labeling of CCR1 with rhodopsin, CD1 lb or TUNEL staining showed expression of CCR1 in the photoreceptor cells, rather in the microglial cells. Partial CCR1 expression was observed in some of the apoptotic photoreceptor cells. Conclusion Expression of CCR1 in the photoreeeptor cells was increased with progression of retinal degeneration in rd mice. Activation of CCR1 may play a role in the photoreceptor apoptosis.