尾静脉注射人脐带间充质干细胞对早期糖尿病大鼠视网膜神经细胞凋亡及胶质纤维酸性蛋白表达的影响

The influence of human umbilical cord mesenchymai stem cells transplanted into the tail vein of diabetic rats on apoptosis of retinal neurons and the retinal expression of glial fibrillary acidic protein

目的观察人脐带间充质干细胞（hUCMSC）对早期糖尿病（DM）大鼠视网膜神经细胞凋亡及胶质纤维酸性蛋白（GFAP）表达的影响。方法健康雄性Sprague-Dawley大鼠70只，随机分为正常对照组（A组）、DM组，分别为12、58只大鼠。DM组经鼠尾静脉注射链脲佐菌素诱导DM模型。成模5个月时，DM组再随机分为DM空白对照组（B组）、磷酸盐缓冲液组（c组）、hUCMSC干预组（D组）。剔除死亡或血糖恢复大鼠，最终每组12只大鼠纳入研究。采用dUTP缺口末端标记法检测各组大鼠视网膜细胞凋亡情况；免疫组织化学染色法及蛋白免疫印迹法（Western blot）检测各组大鼠视网膜中GFAP蛋白表达。结果A组大鼠视网膜各层细胞排列整齐，未见凋亡细胞；B、C组大鼠视网膜神经节细胞层（GCL）、内核层（INL）均可见大量凋亡细胞，GCL水肿；D组大鼠视网膜GCL偶见凋亡细胞、水肿明显减轻。A组大鼠视网膜中GFAP阳性表达主要见于GCL和神经纤维层（RNFL）；B、C组大鼠视网膜中GFAP阳性表达贯穿于内丛状层（IPL）、INL，RNFL、GCL棕黄色颗粒着染加深；D组大鼠视网膜中GFAP阳性表达范围仅见于RNFL、GCL，IPL未见阳性细胞突起。A组大鼠视网膜中GFAP蛋白呈低表达；B、C组大鼠视网膜中GFAP蛋白表达明显增加；D组大鼠视网膜中GFAP蛋白表达较B、c组明显降低。A、B、C、D组之间大鼠视网膜中GFAP蛋白表达比较，差异有统计学意义（F=79．635，P〈0．05）。结论hUCMSC可以抑制早期DM大鼠视网膜神经细胞凋亡与胶质细胞活化。

Objective To observe the influence of human umbilical cord mesenchymal stem cells （hUCMSC） transplanted into the tail vein of diabetic rats on apoptosis of retinal neurons and the retinal expression level of glial fibrillary acidic protein （GFAP）. Methods Seventy clean male Sprague-Dawley rats were randomly divided into the normal control group （group A）, diabetes mellitus （DM） only group （group B）, DM ＋ balanced salt solution （BSS） group （group C）, DM ＋ hUCMSC group （group D）, with 10 rats in each group. DM rats were induced by intraperitoneal injection of streptozotocin. Apoptosis of retinal cells was assayed by dUTP nick end labeling. Immunohistochemistry and Western blot was performed to detect the retinal expressions of GFAP in rats. Results Compared with group A, large numbers of apoptotic cells could be found in the retinal ganglion cell layer （GCL） and inner nuclear layer （INL） of group B and group C, however the apoptotic cells in group D were significantly reduced than group B and C. The expression of GFAP was mainly located in the retinal GCL and retinal nerve fibre layer （RNFL） in group A, throughout the inner plexiform layer （IPL） in group B and C, only distributed in RNFL and GCL in group D. It was obvious that the expression of GFAP in group B and C was higher than group A. Compared with group B and C, the expression of GFAP in group D was significantly reduced. The difference of GFAP expression among the 4 groups was significant （F=79.635, P〈0.05）. Conclusion hUCMSC could inhibit the apoptosis of retinal cells and activation ofglial cells in early DM rats.