移植骨髓间充质干细胞治疗大鼠变性性视网膜病变

Transplantation of bone-marrow derived mesenchymal stem cells to treat rat retinal degeneration

目的观察视网膜下腔移植大鼠骨髓间充质干细胞（rMSCs）治疗碘酸钠诱发的变性性视网膜病变的效果。方法Brown—Norway（BN）大鼠120只，分为碘酸钠注射模型组、rMSCs移植治疗模型组、正常对照组，每组各40只大鼠。模型组大鼠通过尾静脉注射碘酸钠建立变性性视网膜病变模型，正常对照组大鼠给予生理盐水注射。通过视网膜眼底照相、荧光素眼底血管造影、视网膜电图（ERG）和组织学方法鉴定视网膜色素上皮（RPE）和神经视网膜损伤，进一步使用原位凋亡检测（TUNEL）的方法对碘酸钠诱导视网膜变性的细胞病理学变化进行观察。原代分离rMSCs后进行流式细胞术鉴定，将CM—DiI荧光染料标记的rMSCs移植到受体动物的视网膜下腔，采用II缶床检查手段结合组织学检查方法对细胞疗法进行评估。在移植手术后14～60d，检查rMSCs的存活，整合和分化情况。结果在碘酸钠注射14d内，模型组大鼠视网膜的功能逐渐衰竭，呈现时间依赖的关系。模型组大鼠RPE细胞破坏后，光感受器细胞外节出现断裂、缩短的变化直到核固缩。细胞核形态变化和TUNEL标记的结果表明光感受器细胞的死亡主要是凋亡。经过rMSCs移植，供体细胞能够存活并散在分布于视网膜下腔，分化为RPE细胞。ERG检查结果显示，60d后模型组ERGb波改善率为27．80％，模型组ERG震荡电位（Ops）改善率为59．38％；表明rMSCs移植治疗模型组大鼠视网膜功能得到明显保护。结论经过rMSCs移植，碘酸钠诱发的视网膜变性可以得到有效地治疗，移植后的rMSCs能够存活，分化为RPE细胞。

Objective To observe the effects of subretinal transplantation of rat mesenchymal stem ceils （rMSCs） on Sodium Iodate （SI）-induced retinal degeneration. Methods One hundred and twenty Brown-Norway （BN） rats were divided into three groups including SI injection group, rMSCs transplantation group and normal control group, each with 40 rats. The retinal degeneration was induced by caudal vein injection of SI. The retinal pigment epithelium（RPE）and neural retinal were evaluated by ocular fundus photograph, {luorescein fundus angiography （FFA）, electroretinogram （ERG） and histological approach, and TUNEL（terminal deoxynucleotidyl transferase^mediated dUTP nick end labeling ）. CM-DiI- prelabeled primary rMSCs were transplanted into the subretinal space of SI-induced rats. The survival, integration, and differentiation of rMSCs were observed between 14 day to 60 day after the transplantation. Results The rat retinal function was gradually reduced afterl4 days of SI injection, with a time-dependent manner. After the RPE cells were damaged, the outer segments of photoreceptors became disrupted and shortened until karyopyknosis. The nuclear morphology and positive TUNEL labeling indicated that the death of photoreceptor cells was apoptosis. After rMSCs transplantation, CM-DiI labeled donor cells were observed to be scattered in the subretinal space and expressed RPE cell markers. Average amplitude of b wave and Ops （oscillation potential） in ERG improved 27.80~, 59.38~ respectively after rMSCs transplantation. Conclusions Transplanted rMSCs can survive in subretinal space and differentiate into RPEcells, thus cure SI- induced retinal degeneration.