外源性促红细胞生成素对大鼠视网膜脱离光感受器细胞的保护作用

目的 观察外源性促红细胞生成素(EPO)对大鼠视网膜脱离(RD)状态下光感受器细胞的保护作用.方法 采用计算机产生随机数字的方法将162只正常雄性SD大鼠分为正常对照组(NC组)、RD组、RD+磷酸盐缓冲液(PBS)组、RD+EPO 100、200、400 ng组.RD后3 d,采用蛋白免疫印迹(Western blot)检测半胱氨酸蛋白酶3(caspase-3)活性和B细胞淋巴瘤/白血病-XL(bcl-XL)的表达,免疫荧光检测caspase-3活性,脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(TUNEL)检测光感受器细胞凋亡情况.RD后14、28 d,2个月,视网膜组织病理学观察并测量外核层(ONL)厚度.结果 Western bolt检测发现,各组间活化caspase-3条带灰度值差异有统计学意义(F=35.96,P<0.01),bcl-XL条带灰度值差异也有统计学意义(F=30.75,P<0.01).免疫荧光和TUNEL检测发现,caspase-3免疫阳性光感受器细胞数目与TUNEL阳性细胞核趋势表现一致.RD后14 d、2个月,各组间ONL差异有统计学意义(F=21.52,96.25;P<0.01).结论 RD后补充外源性EPO可通过抑制caspase-3活性并增加bcl-XL的表达拮抗凋亡,从而发挥对光感受器细胞的保护作用.

Protective effects of recombinant erythropoietin on photoreceptor cells in rat with retinal detachment

Objective To investigate the protective effect of recombinant erythropoietin (EPO) on the photoreceptor cells in rat with retinal detachment (RD). Methods One hundred and sixty-two normal male rats were randomly divided into normal control (NC) group, RD model group, RD+phosphate buffer solution (RD+PBS) group, RD+EPO 100 ng group, RD+EPO 200 ng group and RD+EPO 400 ng group. Three days after RD, activated caspase-3 and bcl-XL were detected by Western blot and/or immunofluorescence, and apoptosis were measured by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate digoxigenin nick-end labeling(TUNEL). Fourteen and 28 days and two months after RD, the outer nuclear layer (ONL) thickness was measured by histopathologic method. Results Western bolt indicated that the protein level of activated caspase-3 and bcl-XL between six groups were statistically significant(F= 35. 96, 30. 75;P<0. 01). The number of TUNEL positive cells and activated caspase-3 positive cells are consistent with each other in different groups. Fourteen days and two months after RD, the differences of ONL thickness between six groups were statistically significant (F= 21. 52, 96. 25;P<0. 01). Conclusion Supplement of EPO after RD can alleviate apoptosis by inhibiting of the caspase-3 activity and increasing the expression of bcl-XL, thus exerts protective effect on photoreceptor cells.