CXC族趋化因子受体在糖尿病大鼠视网膜中的表达研究

Study on expression of CXC chemokine receptors in retina of diabetic rats

目的研究ELR+CXC族趋化因子受体(CXCR1、CXCR2及CXCR4)和ELR-CXC趋化因子受体(CXCR3)在糖尿病大鼠视网膜中的表达量及定位情况。方法 40只雄性SD大鼠随机分为4组,正常对照组(M0组,n=10)、糖尿病病程2月组(M2组,n=10)、糖尿病病程4月组(M4组,n=10)和糖尿病病程6月组(M6组,n=10)。采用1%链脲佐菌素(STZ)腹腔注射法(60 mg/kg)建立糖尿病动物模型。伊文思蓝灌注视网膜铺片及HE染色法明确视网膜形态学改变;Western blotting法检测各组大鼠视网膜中CXC族趋化因子受体的表达量;免疫组织化学法观察CXC族趋化因子受体在视网膜各层的定位情况。结果ELR+CXC族趋化因子受体CXCR1在M2组表达量高于M0组(P<0.01);CXCR2在M4及M6组的表达量均高于M0组(P<0.05),但M6组表达较M4组下降(P<0.05);CXCR4在M4及M6组的表达量高于M0组(P<0.01),且M6组高于M4组(P<0.05)。ELR-CXC趋化因子受体CXCR3表达量在糖尿病组均高于M0组(P<0.05),且随大鼠月龄增加而升高(P<0.05)。免疫组织化学检测结果显示:CXCR1在各组视网膜中未见明显阳性颗粒;CXCR2仅在M4和M6组视网膜内界膜及内颗粒层偶见阳性颗粒;CXCR3在各组糖尿病大鼠视网膜中均可见阳性异染颗粒,其主要表达在血管周围及神经纤维层;CXCR4在各组糖尿病大鼠视网膜中均有表达,并由主要在视网膜内界膜表达扩展至内颗粒层。结论 CXC族趋化因子受体在不同月龄糖尿病大鼠模型中表达量及部位不同,促血管化因子(CXCR1、CXCR2及CXCR4)与抑制血管化因子CXCR3表达量及部位随糖尿病病程变化,一定程度上可反映糖尿病视网膜病变进展情况,并为早期阻断提供了新的靶点。

Objective To investigate the expression and location of ELR ＋ CXC chemokine receptors （CXCR1, CXCR2 and CXCR4） and ELR- CXC chemokine receptor （CXCR3） in the retina of diabetic rats. Methods Forty male SD rats were randomly divided into normal control group （ M0 group, n = 10）, diabetes mellitus 2 months group （ M2 group, n = 10）, diabetes mellitus 4 months group （ M5 group, n = 10） and diabetes mellitus 6 months group （ M6 group, n = 10）. The animal model of diabetes mellitus was induced by intraperitoneal injection of 1% streptozotocin （ STZ, 60 mg/kg）. The retinal morphology was observed with Evans blue perfusion and HE staining, the expression of CXC chemokine receptors in the retina was detected by Western blotting, and the location of CXC chemokine receptors in epiretinal membranes was determined by immunohistochemical staining. Results The expression of ELR ~ CXC chemokine receptors CXCRI in M2 group was significantly higher than that in M0 group （P 〈 0.01）. The expression of CXCR2 in M4 group and M6 group was significantly higher than that in M0 group （P 〈 0.05）, and the expression of CXCR2 in M6 group was significantly lower than that in Mg group （P 〈 0.05）. The expression of CXCR4 in Mg group and M6 group was significantly higher than that in M0 group （P 〈 0.01）, and the expression of CXCR4 in M6 group was significantly higher than that in M4 group （P 〈 0.05）. The expression of ELR- CXC chemokine receptors CXCR3 in diabetes mellitus groups was significantly higher thanthat in M0 group （P 〈 0.05）, and was increased with the age （P 〈 0.05）. Immunohistochemical staining revealed that there was no obviously expression of CXCR1 in the retina of each group. CXCR2 was detected occasionally in the inner limiting membrane and inner granular layer in M4 group and M6 group. CXCR3 was detected in the retina of all diabetes mellitus groups, and CXCR3 mainly located around blood vessels and in the inner granular layer. CXCR4 was detected in all diabetes mellitus groups, which mainly located in the inner limiting membrane, and gradually expanded to the inner granular layer. Conclusion The expression and location of CXC chemokines receptors are different in rats with different ages. The expression and location of promoting vascularization factors （ CXCR1, CXCR2 nd CXCR4） and inhibiting vascularization factor CXCR3 change with severity of diabetes mellitus, which to some extent can reflect the progress of diabetic retinopathy, and may offer new targets for blocking the progress of diabetic retinopathy at the early period.