SD大鼠视网膜神经节细胞体外分离培养及高糖模型建立

目的：体外分离新生SD大鼠视网膜神经节细胞(RGCs)，建立新生SD大鼠RGCs体外原代培养方法及高糖模型。

方法：取15～20只出生1～3d SD大鼠的视网膜组织，分离纯化RGCs进行原代培养。甲苯胺蓝法及免疫荧光细胞染色法进行鉴定。细胞连续培养48～72h后，随机分为6组并分别加入含不同葡萄糖浓度5.5、20、25、30、35、40mmol/L的培养基培养24、48、72h，采用CCK8法及TUNEL凋亡检测法分析各组细胞存活率及凋亡率。

结果：离体纯化原代培养的RGCs具有典型的细胞形态且生长良好，细胞之间呈小片状融合聚集生长，轴突相互交错成网络状，胞体周围可见细胞光晕。甲苯胺蓝着染细胞胞质中可见结构清晰的尼式小体，神经元率达95%以上。RGCs特异性抗体Thy-1、Brn-3a定体外纯化培养细胞，阳性率达90%以上。CCK8检测发现随着时间及葡萄糖浓度的增加，各组细胞的存活率降低； 在不同葡萄糖浓度干预细胞24h时，各分组之间OD值均小于正常对照组，但与正常对照组相比较OD值大小无差异(均P>0.05)； 随着时间延长，35、40mmol/L葡萄糖浓度干预RGCs 48h，30、35、40mmol/L干预RGCs 72h时的OD值较正常对照组OD值明显降低(均P<0.05)。TUNEL检测发现随着葡萄糖浓度及时间的增加，RGCs凋亡率增加。其中葡萄糖浓度为30、35、40mmol/L培养RGCs 48、72h后RGCs细胞凋亡率与正常对照组相比较有差异(均P<0.05)。

结论：本研究建立的RGCs体外原代培养方法能获得典型且纯度较高的RGCs，随着葡萄糖浓度的增加，体外纯化培养的RGCs存活率降低，凋亡率增加。35mmol/L葡萄糖浓度干预RGCs 48h可为有效诱导RGCs建立高糖模型最佳干预浓度及时间。

In vitro isolation and culture of SD rat retinal ganglion cells and establishment of a high-glucose model

AIM: To isolate the retinal ganglion cells(RGCs)of neonatal Sprague-Dawley(SD)rats in vitro, and to establish the RGCs primary culture method and high glucose model of neonatal SD rats.

METHODS: The retinal tissues of SD rats from 1-3d as the materials were taken, from which the RGCs were isolated and purified for primary culture. Toluidine blue and immunofluorescence staining methods were adopted to identify the cultured cells. After 48-72h of continuous culture, RGCs were randomly divided into 6 groups and cultured in different glucose concentrations of 5.5mmol/L(normal control group), 20mmol/L, 25mmol/L, 30mmol/L, 35mmol/L and 40mmol/L for 24, 48 and 72h, respectively. Finally, the CCK8 method and TUNEL method were adopted to determine the cell survival rate and apoptosis rate.

RESULTS: The primary RGCs purified and cultured in vitro represented typical cell morphology and grew well, the cells were confluent and aggregated in small lamellar manner, while the axons crisscrossed into a network, in addition, cell halo could be seen around the cell body. Nissl bodies with clear structure were found in the cytoplasm of toluidine blue stained cells, the percentage of neurons was more than 95%. RGCs specific antibodies Thy-1 and Brn-3a were employed to identify the purified cells in vitro, and the positive rate reached more than 90%. The CCK8 results showed that the survival rate of cells decreased(OD value decreased)with the increase of culture time and glucose concentration. When the cells were treated with different glucose concentrations for 24h, the OD values of each group were lower than those of the normal control group, but there was no significant difference between the OD values of each group and the normal control group(all P>0.05). With the extension of culture time, the OD values of 35mmol/L and 40mmol/L glucose concentration intervention RGCs 48h, 30mmol/L, 35mmol/L, 40mmol/L intervention RGCs 72h were significantly lower than those of the normal control group, the difference was statistically significant compared with the normal control group(all P<0.05). TUNEL results revealed that the apoptosis rate of RGCs increased with the increase of glucose concentration and time, among them, the apoptosis rate of RGCs cultured in glucose concentration of 30mmol/L, 35mmol/L and 40mmol/L for 48h and 72h was significantly statistical different from that of normal control group(all P<0.05).

CONCLUSION: The RGCs primary culture method established in this study is capable of separating typical RGCs with high purity. With the increase of glucose concentration in the medium, the survival rate of RGCs have been decreased while the apoptosis rate increased. Notably, the 35mmol/L glucose intervention for 48h can be employed as the optimal intervention concentration and time to effectively induce RGCs to establish the high glucose model.