糖尿病大鼠视网膜血流动力学与视网膜血管形态学关系的研究

Relationship between hemodynamic changes of retina and morphology of retinal vessel in diabetic rats

目的应用彩色多普勒超声(CDI)技术和视网膜血管消化铺片技术及组织病理学检查,监控糖尿病视网膜病变(DR)发生发展的过程,研究糖尿病大鼠视网膜血流动力学与视网膜血管形态学的关系。方法给大鼠ip链脲佐菌素诱导成糖尿病模型,分别在造模2、4、6个月时,采用CDI检查测定大鼠视网膜中央动脉(CRA)的血流动力学,应用视网膜血管消化铺片计算内皮细胞/周细胞比值,同时做组织病理学检查。结果在糖尿病病程2个月时,糖尿病大鼠CRA血流流速显著下降,而视网膜血管消化铺片未见异常,在病程4个月和6个月时,视网膜血管消化铺片出现内皮细胞增生,周细胞减少,镜下视网膜内新生血管形成、出血或渗出等病理改变,而此时血流流速减慢严重。结论糖尿病早期,视网膜血流动力学已经出现异常改变,并进行性加重,提示视网膜血流减少、血液灌注不良是DR的重要发病原因。在糖尿病早期、DR发病之前即进行相应的治疗以改善视网膜的血供,可能延缓或逆转DR的发生与发展。

Objective To monitor the development process in diabetic retinopathy （DR） by color Doppler imaging （CDI）, retinal vessel digest preparations, and histopathology, and to investigate the relationship between the hemodynamic changes of retina and retinal vessel morphology in diabetic rats. Methods Diabetic rats were induced by ip administration of Streptozotocin. The hemodynamic changes of central retina artery （CRA） of the right eyes of rats in the model group and control group were detected with CDI in diabetic duration of 2, 4, and 6 months, respectively. The right eyes of rats were dissected to make retinal vessel digest preparations to calculate endotheliocyte/perithelial cell ratio, the left eyes of rats were dissected for histopathology tests. Results There was significant difference of CRA hemodynamics between diabetic and normal rats in diabetic duration of two months. In contrast, the loss of pericapillary cells and hyperplasia endothelial as the only early changes of DR were demonstrated in 4 and 6 months diabetic rats in retinal digest preparations. Under the light microscope, the neovascularization, haemorrhage, and effusion in retina interior were observed at this time. Conclusion The results show that the retinal hemodynamics could display abnormal changes and become more serious with the progress of the disease, and suggest that the reduction of retinal blood flow and blood dabbling be important causes of DR in the early stage of diabetes. In the early stage of diabetes, corresponding treatment should be taken before the onset of DR to improve blood supply of the retina, which may postpone or reverse the incidence and development of DR.